REPORT ON THE CRINOIDEA. 197 



XII.— DESCRIPTION OF THE SPECIMENS. 

 Class CEINOIDEA. 



Order Neocrinoidea. 



Family HolopiDoE, Roemer, 1856 ; emend. Zittel, 1S79, and P. H. Carpenter, 1884. 



Genus, Holopus, d'Orbigny, 1837 ; emend. P. H. Carpenter, 1884. 



A. General Account of the Type. 



Definition. — Basals and radials completely anchylosed into an asjonmetrieal tube- 

 like calyx, -wliich is fixed by an irregularly expanded base. On the upper edge of the 

 cup are five unequal articular surfaces for the attachment of the second radials. Arms 

 ten, massive, and closely inroUed. Disk relatively small, with a central mouth pro- 

 tected by five oral plates, between which and the edge of the cup is a very narrow irregular 

 pavement of smaller plates. Anus probablj^ present, but not yet observed. 



Remarks. — The description of this genus, which was established by d'Orbigny in 

 1837, attracted much attention on account both of the novelty and of the rarity of this 

 singular type. The specimen described by d'Orbigny, which was for a long time unique, 

 was brought from Martinique by M. Sander Rang. It is tetra- instead of penta-radiate 

 as most Crinoids are, and this seems to have caused some misconception respecting its 

 true nature, for it receives no mention whatever in Pictet's Paleontologie ; while 

 Dujardin and Hupd^ expressed their opinion in 1862 that Holopus is not a Crinoid at 

 all, but an altogether different type, probably a Cirripede.^ 



A few years later, however, a normal pentaradiate example was brought up on a 

 fisherman's line from deep water off Barl^ados. It was fortunately acquired by the 

 governor, Sir Rawson Eawson, and was placed by him in the hands of Prof. Louis Agassiz 

 during the stay of the " Hassler " at Barbados in 1872. Prof. Agassiz intended to have 

 published a full description of the specimen, but was prevented from doing so by failing 

 health, and after his death the figures wliicli he had prepared were published by 

 Mr. Alexander Agassiz, together with a short descriptive note by Count Pourtales.^ 



1 Memnire sur une seconde ei3pece vivante de la famille dea Crinoides ou Encrines, servant de type au nouveau 

 genre Holope (Holopus), Gue'rin, Mag. de Zool., 7nie annee, Classe x., 8 pp., pi. 3, Paris, 1837. 

 ^ Op. cit., p. 218. 

 3 Description of a Specimen of Holopus rangi,i from Barbados, Mem. Mus. Cowp. ZooL, vol. iv. No. 8, p. 51. 



