7. Anthozoa (incl. Hydrocorallia). B. Alcyonaria. 35 



which are re-defined. This genus is restricted to the littoral zone of the tro- 

 pical portion of the Indo-Pacific Ocean. The author lays stress on the value 

 of the habitus as a reliable specific character in the Nephthyidae; the spi- 

 cules of the upper and lower cortex and of the canal walls should always be 

 examined. He describes NepMhyigorgia n. 3 sp., which is near Stereonephthya, 

 and in many points exhibits a transition between the Siphonogorgiidae and the 

 Alcyonidse and also shows resemblances to the Nephthyidae. Ster. probably 

 has its centre of origin in West Australia. An account is given of Stude- 

 riotes 4 (2 n.) and of the internal anatomy of semperi. A transverse section 

 of the stem exhibits, from without inwards, a thin cuticle, ectoderm, a firm 

 layer of mesogloea in which lie numerous longitudinally arranged spindles and 

 a network of endodermal cords and canals, and, in the central part of the 

 stem, wide ccelentera separated from one another only by thin partitions of 

 endoderm and mesogloea. The mesenteries have a very strong musculature, 

 the two dorsal ones bear small filaments and, in the lower part of the stem, 

 gonads are present on the mesenteries. The polyp-bearing portions of the 

 colony can be retracted by means of the septal muscles, the outer wall of the 

 colony then bends inwards and can completely close the aperture. There is 

 no sphincter muscle. Each polyp-bearing axis contains the coelenteron of a 

 large terminal polyp, which has a short stomodaeum and thick mesenteries, 

 the two dorsal of which bear small filaments. All the mesenteries have a 

 strong musculature and the muscle fibres are not restricted to one face of the 

 mesentery but are situated, approximately symmetrically, on both sides being 

 placed on mesogloeal outgrowths so that, in transverse section, the mesenteiy 

 presents a pinnate appearance. There is a thick mesoglcea, containing endo- 

 dermal cords and canals, around the coelenteron of the main polyp and con- 

 necting the latter with the ccelentera of the smaller lateral polyps. The endo- 

 derm is a thick layer, that of the lateral polyps is so thick that the cavity 

 of the coelenteron is almost obliterated. The stomodaeum has a well-marked 

 siphonoglyph. The mesenteries of the lateral polyps are thin and their mus- 

 culature weak. The colony consists, therefore, of a relatively small number 

 of large polyps uniting below to form the stem, and in their upper part bearing 

 small secondary polyps. In S. crassa the portion of the coelenteron of each 

 main polyp situated in the stem is very wide, the muscles which are on both 

 sides of the mesenteries are not quite so strong as in semperi, and the 

 muscle pennons disappear in the upper part of the mesentery, which is 

 quite a thin lamella at its attachment to the stomodaeum. There is a large 

 siphonoglyph. The mesenteries of the lateral polyps have, in their lower free 

 portion, a very strong musculature. The coelentera of the lateral polyps are 

 directly connected by short canals. In the mesogloea of the lateral polyps are 

 massive cords of endoderm cells. The extension of the polyp-bearing parts is 

 brought about possibly by the intake of water through the terminal polyp. The 

 author places Stud, (diagnosis emend.) with Fasricularia and Paralcyonium in 

 the Fasciculariidae (diagnosis emend.), and regards jp 7 ., P. and St. as 3 stages 

 of differentiation. In F. the coelentera are connected by basal stolons (Cornu- 

 larid type), but in P. there is no trace of this, its arrangements being of the 

 Alcyonid type, while the heads* of lateral polyps and the presence of Stiitz- 

 biindel in St. suggest a Nephthyid type, but this resemblance may be due to 

 convergence. The author also describes Nephthya 9 (7 n.), Dendronephthya 3 

 (1 n. and 1 n. var. ; a specimen of D. florida attains a height and width of 

 40 and 25 cm. respectively), Stereonephthya 3 (2 n.), Euplexaura 1, Plexau- 

 roides 4, Mopsella 2, Clathraria 1. 



