Narrative of the Voyage of H.M.S. Rattlesnake, Commanded By the Late Captain Owe - Volume 1 by John MacGillivray (book recommendations for teens .txt) 📕

the subsequent subdivisions here adopted.

The order, Polyzoa infundibulata, is divided into three suborders, coinciding very nearly with the Tubuliporina, Celleporina, and Vesicularina of the work above referred to, but as the characters of these suborders are derived from the conformation of the opening of the cell, I have thought it more convenient to name them accordingly. The first suborder, having a round, simple opening to the cell, is here termed the Cyclostomata; the second, with the opening of the cell filled up by a usually thin, membranous or calcareous velum, and with a crescentic mouth provided with a movable lip, the Cheilostomata; and the third suborder, which might perhaps include the Halcyonellea of Ehrenberg, as well as the Vesiculariadae, distinguished by the existence of a more or less well-marked fringe of setae (sometimes only rudimentary) around the opening of the cell when the animal is protruded, the Ctenostomata.

The following synoptical arrangement-which it must be remarked, includes only the genera occurring in the Rattlesnake collection-will serve to indicate the subsequent divisions.

SYNOPTICAL ARRANGEMENT OF THE POLYZOA INCLUDED IN THE RATTLESNAKE COLLECTION.

Suborder 1. CYCLOSTOMATA (Tubuliporina).

Fam. 1. TUBULIPORIDAE. Gen. 1. Tubulipora. Sp. 1. T. phalangea ? 2. Pustulipora. 2. P. australis, n. sp. 3. Idmonea. 3. I. radians.

Fam. 2. CRISIADAE. 4. Crisia. 4. C. denticulata. 5. C. acropora, n. sp.

Suborder 2. CHEILOSTOMATA (Celleporina).

§. 1. UNISERIALARIA.

Fam. 1. CATENICELLIDAE. 5. Catenicella. a. fenestratae. 6. C. hastata, n. sp. ? 7. C. amphora, n. sp. 8. C. margaritacea, n. sp. 9. C. ventricosa, n. sp. 10. C. plagiostoma, n. sp. 11. C. lorica, n. sp. 12. C. cribaria, n. sp. b. vittatae. 13. C. formosa, n. sp. 14. C. gibbosa, n. sp. 15. C. elegans, n. sp. 16. C. cornuta, n. sp. 17. C. umbonata, n. sp. c. inermes. 18. C. carinata, n. sp. 6. Calpidium, n. g. 19. C. ornatum, n. sp.

Fam. 2. EUCRATIADAE. 7. Eucratea. 20. E. chelata. 8. Anguinaria. 21. A. spatulata.

§ 2. MULTISERIALARIA. 1. Articulata. a. internodes elongated, multicellular.

Fam. 1. SALICORNARIADAE. 9. Salicornaria. 22. S. punctata, n. sp. ? 23. S. bicornis, n. sp. 24. S. dichotoma, n. sp. 25. S. marginata, n. sp.

Fam. 2. CELLULARIADAE. 10. Cellularia. 26. C. monotrypa, n. sp. 11. Scrupocellaria. 27. S. cervicornis, n. sp. 28. S. diadema, n. sp. 29. S. cyclostoma, n. sp. 30. S. ferox, n. sp. 12. Canda. 31. C. arachnoides. b. internodes short, 2-4 celled. 13. Emma. 32. E. crystallina. 33. E. tricellata, n. sp.

2. Inarticulata.

Fam. 3. BICELLARIADAE. 14. Bicellaria. 1 34. B. tuba, n. sp. 35. B. gracilis, n. sp. 36. B. grandis, n. sp. 37. B. flexilis, n. sp. 15. Acamarchis. 38. A. neritina. 39. A. tridentata.

Fam. 4. CABEREADAE. 16. Caberea. 40. C. rudis, n. sp. 41. C. zelanica. 42. C. lata, n. sp. ?

Fam. 5. FLUSTRADAE. 17. Flustra. 43. F. pyriformis ? 44. F. denticulata, n. sp. 18. Retepora. 45. R. cornea, n. sp. ? 46. R. cellulosa. 47. R. ctenostoma, n. sp. 19. Eschara. 48. E. lichenoides. 20. Diachoris, n. g. 49. D. crotali, n. sp.

Fam. 6. CELLEPORIDAE. 21. Cellepora. 50. C. bilabiata, n. sp. ?

Fam. 7. GEMELLARIADAE. 22. Didymia, n. g. 51. D. simplex, n. sp. 23. Dimetopia, n. g. 52. D. spicata, n. sp. 53. D. cornuta, n. sp.

Suborder 3. CTENOSTOMATA. (Vesicularina, etc.)

Fam. 1. VESICULARIADAE. 24. Amathia. 54. A. biseriata.

Suborder 1. CYCLOSTOMATA.

Fam. 1. TUBULIPORIDAE.

1. TUBULIPORA, Lamarck.

1. T. phalangea, Couch. Habitat: Bass Strait, 45 fathoms.

A small, imperfect specimen, which may be referred to the variety noticed in British Zoophytes, and figured Plate 46, figures 3, 4.

2. PUSTULIPORA, Blainville.

1. P. australis, n. sp. P. deflexa ? Couch.

Branched dichotomously; branches short, incrassated, truncate. Cells wholly immersed, or about half free, numerous; surface minutely papillose, summits of papillae of a dark brown or black colour.

Habitat: Bass Strait, 45 fathoms; and elsewhere in the Australian seas.

About half an inch high. The stem becomes thicker as it ascends, and divides into two equal short branches, each of which again subdivides into two short truncate branches, in a plane at right angles to the primary division. The cells in the upper part of the stem appear free for nearly half their length, and are gently curved outwards. The surface is covered with pretty regularly and quincuncially arranged minute papillae, the apex of each of which is flattened or rounded, and of a dark brown or black colour. The mode of subdivision of the polyzoary, and the truncated ends of the branches, and the more numerous cells, suffice to distinguish this species from P. proboscidea. The cells in the figure of P. deflexa appear to be much more slender in proportion, and the branches in that species are not truncated, but attenuated at the extremity.

3. IDMONEA, Lamouroux.

1. I. radians, M. Edwards. Ann. de Sc. N. tome 9 page 25 plate 12 figure 4. Retepora radians, Lamarck. Habitat: Bass Strait, 45 fathoms.

One minute specimen, but very perfect, has been examined; but it is undoubtedly the one described and figured by M. Edwards, and noticed by Lamarck as inhabiting the seas of New Holland. M. Edwards' doubt therefore as to this locality is now removed.

Fam. 2. CRISIADAE.

4. CRISIA, Lamouroux.

1. C. denticulata, Fleming. Habitat: Bass Strait, 45 fathoms.

Parasitic upon a species of Salicornaria. The only difference, if there be any, between this form and the British, consists in the rather greater projection or freedom of the extremities of the cells, which are curved towards the front.

2. C. acropora, n. sp.

Cells 9 to 13 in each internode; lateral branches given off between the first and second, or between the second and third cells above a joint. A small conical tooth, sometimes bifid, above and behind the mouth.

Habitat: Bass Strait, 45 fathoms.

A small parasitic species, distinguished from C. denticulata, which it much resembles, by the less average number of cells in each internode, and the less number intervening between the origin of a branch and the joint below it, and by the small conical tooth or tubercle above and behind, or to the outer side of the mouth.

Suborder 2. CHEILOSTOMATA.

§ 1. Uniserialaria. Cells disposed in a simple series.

Fam. 1. CATENICELLIDAE. Cells connected by flexible joints.

5. CATENICELLA, M. Edwards (Lamarck An. s. Vert. tome 2 page 181.)

Cells arising one from the upper and back part of another by a short corneous tube, and disposed in a linear series, all facing the same way, and forming dichotomously divided branches of a phytoid polyzoary; cells geminate at the bifurcation of the branches; each cell furnished with two lateral processes usually supporting an avicularium. Ovicells either subglobose and terminal, or galeriform and placed below the mouth of a cell in front.

This interesting and important genus may be regarded as characteristic, not only of the present collection, but perhaps also of the Australian seas, as far as the Polyzoa are concerned. Thirteen species are here described, and as it has been found extremely difficult in most cases to identify any of them with the very few hitherto noticed forms, the synonyms given must be regarded as at least extremely doubtful.

Each cell arises from the upper and back part of another, with the intervention of a short corneous tube which is prolonged from the interior of one cell to that of the one above. The cell is furnished on each side at the top with a usually well-developed avicularium, in some species of huge size, and in some very minute, or entirely aborted. This avicularian process in most cases supports above a hollow process, which is sometimes closed and more or less elongated, constituting a conical or acerose spine, sometimes open above and assuming the form of a shallow cup or receptacle. In some species both modifications of this portion of the lateral process are met with in the same specimen. This form of spine or cup-as the case may be, is always distinctly separated by a septum from the cavity of the avicularium itself. Below the avicularium there is also in many cases a third distinct cavity which is usually widely open, the opening being covered in very frequently by a convex transparent membrane, and its bottom apparently perforated by several minute foramina-from this part of the lateral process there is in many species a prominent ala or keel prolonged to the bottom of the cell-which ala not unfrequently divides into two branches, which, again coalescing at the bottom of the cell, circumscribe a more or less oval space, the bottom of which is also perforated by minute foramina or apparent foramina, and which is often covered over by a transparent convex membrane. This membrane, however, as well as that which covers in the subavicularian space, is more usually broken off and wanting.

The inferior oval space above described is here termed the lateral area, and it is employed in the specific characters. It would thus be correct to say-that each cell is furnished with two lateral processes, each of which in the fully developed state consists of three distinct compartments-one superior, a cup or spine: a middle one, which is the avicularium: and an inferior; and it would appear that one or more of these elementary compartments of the lateral process may be more developed than the next, or sometimes entirely aborted. The mouth of the cell is situated at the upper part in front, and is of the same conformation as in the rest of the Cheilostomatous suborder. An important generic character consists in the gemination of the cell at each bifurcation.*

(*Footnote. Table 1 figures 1 and 2.)

These characters are common to all the species included in the genus, which furthermore admits of being subdivided into two extremely natural sections or subgenera (or perhaps into three). These subdivisions are named respectively the fenestratae, and the vittatae.

In the fenestrate division, in the whole of which the cells are of larger size and stronger than in the other, the wall of the cell appears to be constituted of at least two distinct laminae. The external lamina, on the front of the cell, is perforated by a certain number of holes, is wanting rather in a certain number of spaces, for which spaces the term fenestrae is employed. These apparent openings do not, therefore, penetrate into the cavity of the cell. But besides the fenestrae, there is, in some cases, a small central opening which does penetrate through the wall. In most cases the fenestrae are arranged in a crescentic, or rather horseshoe-shaped line, indicative, as it were, of the limits of a regular oval space, in the front wall of the cell, the upper part of which oval would be formed by the mouth, and the remainder filled up by the deposition of calcareous matter, as happens for instance in the older cells towards the bottom of the polyzoary in certain Cellulariae, etc.

A further characteristic of the fenestrate Catenicellae is the terminal position of the ovicells. These organs are clearly transformed cells, or cells dilated to considerably more than their natural bulk, and assuming a subglobose form. And what is worthy of remark, these terminal ovicells always have a sessile avicularium on the summit.

In the Vittatae the cell is smaller, and usually more delicate and transparent. They probably want the outer lamina, or have it very thin, and consequently present no fenestrate spaces, and the front of the cell is beset (sometimes very sparingly) with more or less prominent, minute, acuminate papillae. On each side, sometimes on the anterior aspect, sometimes quite laterally, is a