ANGELOPSIS. 309 



'88b, pi. 4, fig. 23), in Dromalia they are clearly tricornuate (Plate 23, fig. 10). 

 Unfortunately no mature tentilla are preserved. But the immature stages which 

 I was able to study have basal thickenings which strongly suggest early stages 

 in the development of an involucre. 



Internal structure of the nectosome and siphosomc. These two regions of 

 the corm are structurally very similar to those of Rhodalia, with the im- 

 portant exception that while there is a shallow hypocystic cavity of consider- 

 able breadth in that genus, in Dromalia no such space is distinguishable. The 

 general pericystic cavity is but little more voluminous here than elsewhere 

 (Plate 24, fig. 4, 5) and connects immediately with the vascular system of the 

 •underlying parts of the corm. A second minor difference is that Haeckel found 

 the bulbous siphosome of Rhodalia traversed by a network of innumerable 

 small canals, while in Dromalia the vascular system is chiefly restricted to 

 near the surface, but few canals penetrating the deeper lying region (Plate 24, 

 fig. 4). The general ground substance of the siphosome is cartilaginous in 

 consistency, and extremely rigid; and this is apparently true of both Rhodalia 

 and Stephalia, as it certainly is of Angelopsis (p. 313). This structure of the 

 siphosome is very different from the condition in Archangelopsis, where the 

 siphosome is a thin-walled bag, enclosing a voluminous hypocystic cavity which 

 communicates freely with the pericystic space. 



ANGELOPSIS Fewkes, 1886. 

 Auralia Haeckel, 1888. 



Rhodaliidae with solid bulbous siphosome traversed by a network of numer- 

 ous canals ; with smooth-walled aurophore lacking papillif orm processes : with 

 very voluminous hypocystic cavity extending to or below the lower end of 

 the siphosome. Tentilla present (?). 



Two species have been described which can be referred to this genus, Ange- 

 lopsis globosa Fewkes, taken by the "Albatross" in the Gulf Stream, and Auralia 

 profunda Haeckel, from "the depths of the tropical Atlantic." 



Fewkes's two descriptions ('86, '89a) have been thoroughly reviewed and 

 compared with Archangelopsis by Lens and Van Riemsdijk. Fewkes was able 

 to make out many of the important anatomical features of the genus, but his 

 material was in such condition that he could trace but few of the external fea- 

 tures, i. e. the structure of the cormidia or arrangement of nectophores, which 

 might prove of specific importance. It is probable that the conformation of the 



