MUSEUM OF COMPARATIVE ZOOLOGY. 17 



No. 2. — List of the Ecldnoderms sent to different Institutions in 

 Exchange for other Sjjecimens, with Annotations. By A. 

 Agassiz.* 



Phyllacanthus Br. Prod, (emend.). — Leiocidari s Desor, Synop. 



Phyllacanthus imperialis Br. 



Under the name of Cidaris imperialis two very distinct species have 

 been confounded, one of which (Ph. fustigerus A. Ac) is found in New Hol- 

 land and the East India Islands, while the other species (Ph. imperialis), of 

 which a good figure is given by Seba, is found at Zanzibar and Mozambique. 



Cidaris Klein, Disp. Nat. Echin. (emend.). 

 This genus is here limited in such a way as to include only the following 

 and allied species : — 

 Cidaris Thouarsii Val. Ag. Cat. Bais. — Panama. 

 Cidaris tribuloides Lamk. An. s. Vert. — Bed Sea. 

 Cidaris annulata Gray. Proc. Zool. Soc. 1855. — Florida. 

 Cidaris baeulosa Lamk. An. s. Vert, (non Mich.). — Bed Sea. 



A good figure of this species is given by Savigny, Descrip. Egypt. Zool., 

 PI. 7, fig. 1, which is very different from the figure given by Michelin, Mag. 

 Zool., IV., PL 8. The last is a Prionocidaris, and probably the C. pistil- 

 laris Lamk. 



Gymnocidaris A. Ag. 



Gymnocidaris metularia A. Ag. 



Syx. Cidaris metularia Lamk. An. s. Yert. — Zanzibar. 



Gymnocidaris minor A. Ag. 



This species, which is found at the Sandwich and Kingsmills Islands, 

 differs from the G. metularia in the proportions of the ovarian and ocular 

 plates. The genital plates are much smaller than in the C. metularia, in 

 which they cover nearly the whole of the abactinal system. 



Orthocidaris Ag. 

 Orthocidaris hystrix Ao. 



Syn. Cidaris I/ystrix Lamk. An. s. Vert. — Nice. 



Orthocidaris affinis Ag. 



Syn. Cidaris affinis Phil. Wieg. Archiv., 1845 ; Cidaris Stokesi Ag. 

 Cat. Rais. — Mediterranean. 



To this genus belongs also Cidaris papillata Flf.m. 



* Descriptions of the new genera based upon species already known may be 

 found in the "Illustrated Catalogue of the Museum." — L. Agassiz. 

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