164 HAWAIIAN AND OTHER PACIFIC ECHINI. 



Key to the Species of Agassizia. 



Posterior petals well developed, more or less depressed scrobiculata. 



Posterior petals little developed, flush with test excentrica. 



Agassizia scrobiculata. 



Valenciennes, 1846. Voy. Venus. Plates, Zoophytes, 1, figs. 2-2/. 



This species occurs in shallow water along the western coast of tropical 

 and subtropical America. I have examined a number of good specimens, in 

 search of pedicellariae, but with little success. The only kind found, and that 

 very rarely, is a tridentate, which is not at all distinctive. The valves are 

 .25-50 mm. long, with the narrow, high base and broad, leaf-shaped blade of 

 about equal length and breadth; the margin of the blade is rather sharply ser- 

 rate. Apparently the distinctly subarenaceous life has led to gradual loss of 

 the pedicellariae as it has in many clypeastroids. 



Agassizia excentrica. 



A. Agassiz, 1869. Bull. M. C. Z., 1, p. 276. 



Of this West Indian species there are no specimens except bare tests avail- 

 able, so I am unable to give any information about the pedicellariae. 



Pericosmus. 



Agassiz and Desor, 1847. Ann. Sci. Nat. Zool.. (3), 8, p. 19. 



Type, Micrasler edwardsii Agassiz, 1840. Cat. Syst. Zool., Ect. 2 (nomen nudum), = Schiiaster agassizii 

 Sismonda, 1841. Mon. Ech. Foss. Piemonte, p. 23. 



The discovery of a Recent species of this genus by the Investigator in 

 shallow water on the eastern side of the Bay of Bengal is one of that vessel's 

 many important contributions to marine zoology. By an unfortunate typo- 

 graphical error in Koehler's account of the species (1914. Ech. Indian Mus. 

 Spat., p. 133) the longitude of the type locality is made to read 29° 55' E. instead 

 of 92° 55' E. This interesting specios was called by Anderson, its discoverer, 

 Pericosmus macroncsius, and Dr. Koehler has retained the name. 



