7. Anthozoa (incl. Hydrocorallia). C. Hydrocorallia. 19 



outgrowth is connected to the mesentery by a thin stalk. The egg gives rise to a 

 morula and the embryos, when liberated, are ciliated and spirillum-like, or may 

 be balloon-shaped resembling those of Corallium rubrum. The stomodaeum is 

 formed by an ectodermic invagination and a siphonoglyph soon appears. Rolandia 

 n. coralloides n. has been hitherto confounded with S. coralloides which it closely 

 resembles. In a postscript the author states that Fascicularia Edwardsi is really 

 a Paralcyonium and he therefore renames it P. Edwardsi, and Haimea fimebris 

 is probably merely a young Alcyonacean which would later have formed a colonial 

 growth by budding. 



Ashworth confirms observations made on Xenia Hicksoni [see Bericht f. 1899 

 Coel. p 10] by examination of 5 other species (1 new). In all dorsal mesenterial 

 filaments only are present and some of the cells of the stomodaeum are glandular. 

 In .A', viridis young ova are found along with well-developed sperm-sacs on the 

 same mesenteries. All the other specimens examined are dioecious. The ripe ova 

 resemble those of Alcyonium. 



Johnson ( 2 ) suggests that Pleurocorallium grows upright, in the path of a sub- 

 marine current, with all the polyps opposed to the oncoming stream. 



Lindstrbm" gives an account of the structure of the Heliolitidae, their geo- 

 graphical and geological distribution and a systematic synopsis of the genera and 

 species. The following are described: HeMolites 8 (4 n. and 2 n. var.), Prohelio- 

 lites 1, Plasmopora 12 (8 n. and 1 n. var.), ProporaS (5 n. and In. var.), Diploe- 

 pora 1, Coccoseris 4 (1 n. and 1 n. var.), Protaraea 1, Cosmolithus n. 2, Acantho- 

 litltus n. 2, Camptolithus n. 1, Pycnolithus n. 1. 



According to Gregory ( 2 ) the calices of Polytr&tnacis are cylindrical tubes, which 

 are marked internally by longitudinal ridges and are covered by transverse tabulae. 

 Between these are smaller ccecal tubuli. This structure agrees with that of the living 

 Helioporidae and the Palaeozoic Heliolitidae. P. agrees with the latter in the 

 presence of an aureole of larger coeca, the closure of dead calicles by crenenchy- 

 mal overgrowth and the inconstancy of the septa in the lower parts of the calicles. 

 It is allied to Heliopora by equally striking points of resemblance, such as, its 

 fluted calicular walls with their numerous irregular septal ridges, the granular 

 external surface with its circum-calicular ring of septal teeth. Therefore the 

 Heliolitidae and Helioporidae are linked together by P. Heliopora may have 

 descended from the Heliolitidae by reduction in size and consequent increase in 

 number and variability of arrangement of the coenenchymal coeca. (A new species 

 of H. is described from the Cretaceous of Somaliland.) 



G. Hydrocorallia. 



See Fowler and supra p 18 Hickson( 1 ). 



Hickson( 2 ) states that the presence or absence of ampullae in Millepora cannot 

 be used as a diagnostic character as they have been found in fertile specimens 

 of almost all forms of the genus. Hitherto only male medusae of M. have been de- 

 scribed. Immature female medusae about 0,4 mm in diameter are found, each 

 lying in an ampulla and attached by a stalk to the innermost wall of the ampulla. 

 The umbrella is thin and slightly swollen at the margin, it consists of a median 

 lamella of endoderm covered on each side by ectoderm, it is without canals, ten- 

 tacles and velum. The cavity of the umbrella is almost filled with a swollen nia- 

 nubrium on the apex of which is the mouth. The gastral cavity, which usually has 

 4 radial cceca, communicates with the canals of the coenenchym. Around the mouth 

 is a broad band of young ova. The mature medusae are about 0,6 mm in dia- 

 meter and bear usually only 3 or 4 large ova, the manubrium being tri- or quadri- 



