48 IMBRYOLOGICAL MONOGRAPHS. 
26. The oldest stage raised artificially ; near the end of October. Six of the caleareous septa overtop the other 
six, and a new series of 12 additional septa is faintly indicated ; the columella (col/.) is already formed. 
This individual is distinguished by a very considerable development of the epitheca. }. 
27. A much further developed stage, nearly 2mm. high. There are 24 septa which fall into three orders 
according to their relative sizes. The epitheca is not visible, as it does not reach to the margin of the 
cup. f. 
28. Almost fully developed single individual with 48 septa, 12 of which overtop the others. Ld 
Subsequently 48 new septa, alternating with those already formed, make their appearance, and the main 
septa are at the same time increased in number from 12 to 24. 
29-42. Corallium rubrum. From Lacaze-Duthiers, Histoire naturelle du Corail, ete. Paris: 1864. Pls. L, II., 
XJ., XIV., XV., XVII-XIX. 
29. One of the many forms assumed by the ciliate larva in its natural position, with the mouth-end downwards, 
30. Another, more worm-like form of the ciliated larva (compare corresponding stage of Astroides, fig. 1). 
31. One of the stages of transformation from the worm-like to the disk-like form. The aboral region becomes 
enlarged, and the oral end sinks in. 
32. An expanded ‘‘ odzoite” (animal developed from an egg) attached to a rock ; the latter not reproduced here, 
33. An oozoite still older than the preceding, though still simple. Expanded and seen from the oral side. 
34. The same obzoite seen in fig. 32, but in a contracted condition. 
35. One of the tentacular arms of the adult, seen in profile. In this position the barbules are seen to be directed 
obliquely from above downward, and from within outward. 
36. Oral view of a larva several days after its metamorphosis. The central part around the mouth (c) is already 
elevated and forms a bowrrelet ; the base is not so regularly circular as it was at first, since it commences 
to spread itself over the body to which it is attached. 
37. Extremity of a barbule from a tentacle of an adult, magnified 250 diam. ec. External cell-layer. en. Large 
cells forming a network and bearing vibratile cilia. : 
38. Spicules which are exposed on tearing away the epidermis from the adult. 
39. Nematocysts from the adult ; one with the mother-cell still surrounding the nematocyst— or internal cap- 
sule — with its spiral filament. 
40. Portion of a radial fold (mesentery, m nt) bearing (1) at ov. an egg, the capsule (cap.) of which has in part 
fallen away, and the vitellus (vit.) of which presents a very distinct clear spot (n/!), corresponding to the 
transparent (germinative) vesicle, in the middle of which are to be seen the germinative spots (nl/.); (2) at 
te. a capsule in process of development, remarkable on account of an apparently empty space (A) surrounded 
by a cellular band (x) which lines the capsule ; this is a testicle. 
41. A small rock to which are attached three zoanthodemes, the polyps of 2 and 3 having been destroyed. 
3. The beginning of the corallum ; a plate with irregular sides covered here and there with small project- 
ing corpuscles bristling with points. 2. Exhibits an early form of the corallum. It consists of an irregu- 
Jar plate, curved into the shape of a horse-shoe, formed of masses of agglomerated spicules. The general 
cavity of the body of the polyp occupies the interior of this curve, and consequently the solid plate is 
formed, as may be seen at 1, in the midst of the sarcosoma between the external and the internal surfaces, 
42. Zoanthodeme composed of one obzoite (1), and three ‘‘ blastozoites”’ (budded individuals), 2, 3, 4. 
43, 44, 46. Gorgonia verrucosa. From G. yon Koch, Vorliufige Mittheilungen iiber die Gorgonien (Aleyonaria 
axifera) von Neapel und iiber die Entwicklung von Gorgonia verrucosa. Mittheilungen aus der Zoolo- 
gischen Station zu Neapel, Bd. III. 1882. Figs. 10, 13, 15. 
43. Section through an egg before the segmentation spheres have been differentiated into distinct layers. The 
outer cells are somewhat smaller than the inner, and all possess distinct nuclei. The latter appear to be 
wanting in some of the cells simply because lying outside the plane of section. 
44, Longitudinal section of an attached individual, showing the thin layer of ectoderm infolded to form the 
pharyngeal sac which opens into the entodermie cavity helow. 
45. Nore. — Figures 45 and 16 have been accidentally transposed by the lithographer, For explanation of 45 
see above. 
16. Gorgonia verrucosa. From A. O. Kowaleysky, Observations on the development of the Ccelentrata (cited 
above). Taf. V. fig. 19. Ciliated larva. There are to be distinguished two layers in the entoderm. The 
peripheral layer (en.) is striate, indicating its composition out of cylindrical cells, with irregularly arranged 
nuclei ; this merges into the inner layer (en’.) which is granular, filled with highly refractive spherules, and 
is ciliate. {The cilia are not figured by the author.) The latter is considered equivalent to the yolk-mass 
of Aleyonium and of Astrea. 
46. Four cells of the ectoderm, one of which has migrated into the underlying mesodermie layer (Ziwischensub- 
stanz) and shows at one side of its nucleus the eross section of a spiculum which is being formed within it. 
The same cell somewhat more enlarged is figured near by. 
