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. 



Another specimen of P. pectoralls 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 consideral)ly 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 

 anteriorly ; 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, differing in the same way, therefore, in 

 all these characters from the African specimens. Theactinal membrane 

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

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

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

 differences are, therefore, found in the form of the actinal and anal 

 areas and the character 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. pectoralh 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. 

 Ophiuroidea. 

 Ophiothela mir.ibilis Verriii, (pp. 268, 376). 



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

 and Gulf of Foiiseca, in addition to Panama and Pearl Islands. In 

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

 Maricea and Gorgonidce. The genus appears to be widely distribu- 

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

 Melitodes vlrgata V. at the Feejee Islands. A species occurs at 

 Japan, on 3Ioj)sella Japonica V., and Dr. Ltitken has observed one on 

 a Parisis from the China Seas. 



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



