292 T. A. STEPHENSON 



less definitely (the distinction not necessarily externally clear) into an 

 extensive scapus (to which usually adheres a rougliish brown cuticle, 

 much or little of it) and a more delicate capitulum or puffy marginal 

 region, the ectoderm of which may contain spirocysts. Distinct fosse. 

 The tentacles are short knobs, sometimes \vith stems, arranged so that 

 two communicate with each main exocoel, and two or three with each 

 main endocoel (see Part II, Text-fig. 14, a). Besides being in short 

 radial rows they are so placed as to form cycles which alternate, though 

 not in the genuine ' Actiniine ' way. They are some simple, some 

 lobed, and in a living specimcMi one can distinguish different tentacle- 

 forms for the dillVrent concentric rings. Sphincter fairly to very strong, 

 circumscribed, with a heavy central axis of mesogloea (see Part II, 

 Text-fig. 13, b). Radial musculature of disc and tentacles where present 

 curious, chiefly mesogloeal. All stronger mesenteries perfect, fertile, 

 with filaments and retractors ; the retractors very unusual, powerfully 

 circumscribed (see Part II, Text-fig. 4, b), and attached to the mesentery 

 by one edge only for part of their extent, and with an axis of mesogloea. 

 Thei'e may be additional weak mesenteries beyond the main macro- 

 cnemes. 

 Species : 



A. augusta, Gosse, 1860, p. 283. (See Faurot, 1895.) 



A. heterocera, Thompson, 1853. 



A. regalis, Andres, 1883, p. 496. (See Carlgren. 1900. short 

 paper on Stichodactylines, p. 279, &c.) 



? A. nymphaea, Hertw., 1882, p. 38. 



I have personally studied A. augusta, both alive and 

 anatomically, and I do not know why Andres assumed it to be 

 the same as his A. regalis. It is not impossible that 

 C apnea, Forbes, is the young of A u r e 1 i a n i a ; be_youd this 

 suggestion it cannot yet be allocated. Then there is the 

 question of Hertwig's genus Leiotealia. It lias generally 

 been assumed (and I shared the idea formerly) that this is 

 identical with E p i a c t i s or I s o t e a 1 i a , Init this overlooks 

 certain details of its structure. I have recently been able to 

 investigate two species of Aureliania, A, a a gust a and 

 a possibly new one, and on re-reading Hertwig's description in 

 the light of this, it becomes evident that in all features one can 

 be sure about the two genera really share essentials. An 

 examination of the original Challenger specimen confirmed the 

 idea. The one uncertain though necessary poitit is that it is 



