572 Verrill, Notes on Radiata. 



end narrowed and pointed. The mouth is not so broad transversely, 

 but is more produced and rounded anteriorly. Both these areas are 

 covered by numerous, small, crowded, polygonal plates. 



Anotlier specimen of P. pectoralis from Tampa Bay, Florida, in the 

 Museum of Comparative Zoology, which I have also had an opportu- 

 nity to compare with the African specimens, in company with Mr, A. 

 Agassiz, differs considerably in form from the West Indian specimens, 

 of similar size, and if all the specimens from that region should prove 

 to have the same characters, it ought to be regarded as at least a 

 marked variety. This specimen is of about the same size as the 

 larger African specimen, and agrees nearly with it in form, though it 

 is somewhat more depressed and the sides are less abrupt, especially 

 anterioi'ly ; the anterior end is even less emarginate ; and the 

 ambulacral farrow less sunken, with small erplates and more numer- 

 ous pores. The ambulacral petals are not so narrow and oblong as 

 in the West Indian specimens, though much more so than in the 

 African. The ovarial openings are small and round ; the fasciole wide; 

 the plastron oblong ; the large tubercles and the mouth and anal 

 areas are as in the typical form, diifering in the same way, therefore, in 

 all these characters from the African specimens. Theactinal membrane 

 is covered with niimerous, small, crowded, polygonal plates. The anal 

 area is also covered with small, crowded, polygonal plates, much more 

 numerous than in P. Afrlcanus. The most constant and important 

 diiferences are, therefore, found in the form of the aetinal and anal 

 areas and the cliaracter of their plates ; the size and form of the ovarial 

 openings ; the width of the fasciole ; and the form of the plastron. 



A large specimen of P. pectoralU from Turk's Island, in the 

 Museum of the Boston Society of N atural History, is 9 inches long ; 

 6-75 wide; 2-50 high. 



Pacific Species. 

 Opiiiuroidea. 

 Ophiothela mir.^bilis Veniii, (pp. 268, 376). 



This species has been received from La Paz, Cape St. Lucas, Corinto, 

 and Gulf of Fonseca, in addition to Panama and Pearl Islands, In 

 all cases it was found clinging in large numbers to the branches of 

 Muricea and Gorgonlcke. The genus appears to be widely distribu- 

 ted in the tropical parts of the Pacific Ocean, 0. Damn V,* lives upon 

 Melitodes virgata Y. at the Feejee Islands. A species occurs at 

 Japan, on Mopsella Japonica V,, and Dr, Ltitken has observed one on 

 a Parisis from the China Seas. 



* Proceedings Boston Soc. Nat. Hist, xii, p. 391, 1869. 



