NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 341 



Moira clotho^^ (Michelin) 

 Plate 64, Fig. 65 



Moera clotho Michelin, 1885, p. 247. 

 Moira clotho A. Agassiz, 1872a, p. 147. 



H. L. Clark, 1917, p. 196, pi. 156, figs. 5-7. 



This odd, highly specialized Spatangoid is easily recognized by the 

 deeply sunken, narrow, paired petals and even more deeply sunken anterior 

 petal which presumably serves as a brood pouch for the young. The genus 

 includes several species and ranges from the southeastern coast of the 

 United States and the western coast of tropical America to Japan and 

 Australia, to Suez, and Zanzibar, but apparently does not occur in Euro- 

 pean seas or on the west coast of Africa. The Velero met with it at 4 widely 

 separated stations. There are 35 specimens altogether but more than half 

 are very small, 5-10 mm long, and none are very large. These small ones 

 are chiefly from Ecuador in 1 or 2 fms. The finest specimens are from the 

 upper end of the Gulf of California, near Consag Rock, on a bottom of 

 brov/n mud in 21 fms. The largest are about 26 mm long, by 22 mm wide 

 by 18 mm high. They are almost pure white in color with the lateroanal 

 f asciole yellow. 



Distribution. — Gulf of California to Ecuador. 



Type. — Paris Museum? 



Type locality. — Mazatlan, Mexico. 



Depth. — 1-21 fms. 



Specimens examined. — 35 specimens from 4 stations. 



Family Spatangidae 



Brissopsis pacifica (A. Agassiz) 



Plate 65, Figs. 66-67 



Toxobrissus pacificus A. Agassiz, 1898, p. 83. 

 Brissopsis pacifica Mortensen, 1907, p. 168. 



H. L. Clark, 1917, p. 203. pi. 155, fig. 1. 

 This is apparently the commonest Spatangoid in the Eastern Pacific. 

 The Velero took 674 specimens at 65 stations. They range in size from 

 very young (6x5 mm) to big adults (57x47x31 mm), but the very 

 great majority are less than 35 mm long. As both Brissopsis pacifica and 

 Brisaster townsendi were taken at 6 stations, it is not surprising that hy- 

 brids occur apparently with considerable frequency. While the two species 

 are alike in dull coloration, pacifica tends to lighter shades and the fascioles 

 are more conspicuous. There is some evidence that muddy or even foul 



18 In Grant and Hertlein, 1938, the specific name is consistently misspelled 

 'clothro." H.L.C. 



