A. E. Verrill — Bermudian and West Indian Reef Corals. 151 



Breadth of the type, which is a single frond, 400 mm by 150 mm ; 

 thickness 5 mm to 0.5 mm or less ; at 25 mm from the edge, 'about l mm 

 thick ; diameter of larger calicles, mostly 4 to 6 mm . 



The type is from Turk's Island, W. I. (Mns. Yale University). 

 It is a rare species in American collections. No. 850. 



This is, perhaps, one of the species that have been confounded 

 under the name of elephantotus Pallas, a very different East Indian 

 species, and the type of Mycedium (see p. 134 above). The present 

 species is destitute of the rough serrations and spinules of that species 

 and differs in many ways, though it grows in a similar form. This 

 may, however, be the elephantotus Edw. and Haime ; but their 

 synonymy does not apply to it. 



Whether this is the form united to A. fragilis by Gregory under 

 the name of elephantotus I do not know. Neither can I tell whether 

 it be the elephantotus of Pourtales, or of Vaughan (op. cit., p. 67), 

 for they give no descriptions. But it is not the elephantotus of 

 Oken, nor of Ehrenberg, nor of Dana, nor of Esper. 



It is quite distinct from A. fragilis, though it grows in similar 

 shaped, thin fronds. But the fronds of this species are much larger, 

 thicker, and firmer. The calicles are much larger, more appressed, 

 more prominent proximally, and much deeper. The collines are 

 much shorter, larger, higher, and much more irregular. The septa 

 and septo-costae are also quite different. 



Siderastraea siderea (E. and Sol.) Blainv. 



Madrepora siderea Ellis and Sol., op. cit., p. 168, pi. xlix, fig. 2, 1786. 



Astrea siderea Lam., Hist., ii, p. 267, 1816. Lesueur, op cit., p. 286, pi. 

 xvi, fig. 14, 1820. Lamx., op. cit., p. 60, pi. xlix, fig. 2, 1824. Edw. and 

 Haime, Hist. Corall., ii, p. 509, 1857. Gregory (pars), op. cit., p. 278, 1895. 



Siderastraea siderea Blainv., op. cit., p. 335, 1830; Man. Actin., p. 370, 1834. 

 Edw. and Haime, Monog., p. 141, 1849. Verrill, Bull. Mns. Comp. Zool., i, 

 p. 55, 1864. Pourtales, Reef Corals, p. 81, 1871. Vaughan, op. cit., p. 62, 

 1901. Verrill (pars), these Trans., x, p. 554, 1900. 



Pavonia siderea Dana, Zooph., p. 331, 1846. 



Siderastrma grandis Duncan, op. cit., p. 441, pi. xvi, figs. 5a, 6, 1863, fossil, 

 (t. Vaughan). 



Plate XXX. Figures 2, 3. % 



This coral forms large, compact, hemispherical masses up to 2 feet 

 or more in diameter. 



The calicles are usually deep, narrow at the bottom, and larger 

 than in either of the other American species (usually 5-6 mm in greater 

 diameter when full grown). They are angular, mostly pentagonal 



