MATTHAI— RECENT COLONIAL ASTR^ID^ - 31 



calicoblastic layer — containing usually a dark-stained spot and surrounded by a little 

 irregular cytoplasm ; sometimes a network may be discerned within the nuclear mem- 

 brane *. 



In two polyps of Cyphastrea serailia (Forsk.) certain structures are present in the 

 same position as the ova, which I am led to conclude are mature testes (PI. 1, fig. 9). 

 Each of these is circular in transverse section or laterally compressed, and contains 

 innumerable minute triangular-shaped spermatozoa stained dark in iron-haematoxylinf. 

 Germ-cells, similar to those surrounding the eggs, are also seen scattered around the testis. 



In some female polyps small groups or follicles — round or adpressed — of germ-cells 

 are found to lie in the mesenterial mesoglgea, behind, in front of, or on each side of the 

 large ova ; the cells being either massed together or surrounding a space in the centre of 

 the follicle. In a polyp of Cyphastrea serailia (Forsk.) (from the same colony from which 

 the male polyps were taken) in which ova were found in three of the primary mesenteries 

 arranged in single rows, germ-cells were present massed together in small follicles and 

 also surrounding the eggs (PL 1, fig. 10). In a polyp of Cylicia in which ova were seen 

 in most of the mesenteries in one or more usually two rows, the follicles lay mostly behind 

 the ova, each usually with a space in its centre. In some serial sections of Gardiner's, 

 named Prionastrea ahdita, ova of varying size wei'e to be seen in most of the mesenteries, 

 arranged in rows up to six or eight, along with as many groups of germ-cells. In another 

 polyp of Cylicia a number of such follicles \ were present in the mesenteries, and occasion- 

 ally structures resembling the mature testes in Cyphastrea serailia ; in some of the 

 follicles both germ-cells and spermatozoa appear to be present ; no ova could however be 

 found anywhere in this polyp. 



From the above observations I am led to make the inference that both ova and 

 spermaries may develop from the same kind of follicles, that an ovum is only one of the 

 germ-cells in a group which has grown at the expense of the others §, in support of which 

 it may be added that small ova were to be found in the midst of a few of the follicles. 

 The cells that invariably surround the ova are, on this suggestion, to be regarded as the 

 remnants of the original follicles (PL 5, fig. 49). Further, the case of Cyphastrea serailia 

 suggests that both male and female polyps may occur in the same colony at the same time. 



In the GSise o£ Flabellum, Gardiner regarded such groups as composed of " sperma- 

 togens" and a few ova which he noticed along with the follicles as due to protandry 



* I have found similar germ- cells surrounding some of the ova in Gardiner's sections of the polj^s of 

 Cosnopsammia and Flahellum. 



t The appearance is similar to Ashworth's figure of a spermary of Xenia hicksoni (2, p. 245, pi. 27, fig. 33), 

 and to van Pesch's figures of testis-follicle.s from the mesenteries of Stichopathes (111, pi. VII, figs. 2 and 4) ; 

 the latter author describes the spermatozoa as possessing long tails, and observed them even in the tentacles, 

 but he has not given figures of isolated spermatozoa showing the tails. Lacaze Duthiers figured mature 

 spermatozoa from Cladopsammia rolandi, which have a triangular head with a long flagellum proceeding from 

 the centre of its base (92, pi. 11, fig. 7). In the spermatozoa of Cyphastrea serailia, perhaps the tail has been 

 lost or has not yet developed. 



X Professor V. H. Blackman after examining these bodies tells me that they do not show any plant 

 characters and cannot be spores of algae. 



§ Hickson (70) has also made a similar observation of ova developing in groups of cells in Alcyonium 

 digitatum. 



