MUSEUM OF COMPARATIVE ZOOLOGY. 359 



No. 12. — List of Holothuridce from the Deep-Sea Dredgings of 

 the United States Coast Survey. By L. F. de Pourtales, 

 Assist. U. S. Coast Survey. 



(Communicated by Professor B. Peirce, Sup't U. S. Coast Survey.) 



The Holothurians obtained in deep water off the Florida reef are 

 few in number, and are very closely allied to, if not identical with, 

 those of the deep-sea fauna of Norway. 



The littoral species so abundant on the reef, and in the shallow waters 

 encompassed by it, do not appear to extend into even moderate depths 

 outside, — at least, they were never found in the dredge. 



Cuvieria operculata Pourt. (C. squamata Koren ? Bull. Mus. 

 Comp. Zool. No. 7.) 



A satisfactory comparison of the two species could not be made from 

 want of well-determined specimens of the northern species. From C. 

 Fabricii it is easily distinguished by the suckers on the ventral disk, 

 which in C. operculata are always in a single row on the circumference 

 of the soft disk, and a single row in the marginal plates, whilst in C. Fab- 

 rieii they form a dense band of three or four rows. Two rather muti- 

 lated specimens, without names, in the Museum of Comparative Zoology, 

 received from Professor Sars, and which are probably C. squamata, 

 have the suckers disposed as in C. operculata. The granulation of the 

 scales in the latter is finer than in the two northern species. 



It is not very rare in 120 to 135 fathoms. 



Thyonidium conchilegum Pourt. Ibid. = Th. pellucidum 

 Vahl. ? 



Thyonidium gemmatum Pourt. One young specimen off Tor- 

 tugas, in sixteen fathoms. 



Echinocucumis typica Sars. In 320 to 350 fathoms. 



Cucumaria frondosa Gunner. A rather small specimen of 

 Ilolothurian, dredged in 118 fathoms, cannot be distinguished from this 

 species by any satisfactory characters. The skin contains only a few 

 calcareous needles and no plates. Its color was milk-white with yellow 

 spots. 



