Genera Pseudopygaulus, Tracliyaster, and DItremaster. 335 



aster cavernosus, A. Agassiz has described and drawn female 

 specimens with two genital pores and an extended madre- 

 porite, the males having three pores (' Challenger ' Report, 

 1881, pi. XX. a. fig. 19). According to the proposed generic 

 changes females and males will be in different genera ! It is 

 difficult to understand how H. Branderianus, Forbes, can be 

 a Trachyaster and also a Ditremaster^ according to M. Cot- 

 teau. We cannot agree to the change of generic title of these 

 species, and therefore we restore them to their previous 

 position in Hemiaster. 



IV. 



The following is, in our opinion, the correct synonymy of 

 the forms which we have considered in this communication : — • 



Genus EOLAMPAS, Dune. & Sladen, 1882. 



Syn. Petalastei; Ootteau, 1884. 



Pseudopyffaulus, Coquand (name without definition), 1862 ; Oott. 

 1885. 



Eolampas Trigeri^ Coquand, sp., 1862. 

 Eolampas huccalis, Peron et Gauthier, sp. 

 Eolampas Gauthieriy Cotteau, sp. 

 Eolampas Toucani^ Cotteau, sp. 

 Eolampas ayitecursor, Dune. & Sladen. 

 Eolampas excentrtcus, Dune. & Sladen. 



Genus Hemiaster, Desor, 1847, et auctorum. 



Syn. Trachyaster, Pomel, 1883. 

 Mecaster, Pomel, 1883. 

 Opissaster, Pomel. 

 Ditremaster, Munier-Chalmas. 



Hemiaster Branderianus, Forbes. 

 Hemiaster princeps^ Bittner. 

 Hemiaster Archiaci, de Loriol. 

 Hemiaster decip)iens, Dune. & Sladen. 

 Hemiaster apicalis, Dune. & Sladen. 



