158 Bulletin American Museum of Natural History [Vol. XLVIII 



There are some good representatives of this species in the present 

 collection and they show no little diversity in form. For example, one 

 42 mm. in diameter is 24 mm. high, v.d. thus equal to less than .60 h.d., 

 while another specimen 58 mm. in diameter is 41 mm. high, v.d. equaling 

 more than .70 h.d. In the best-preserved specimens the spines are nearly 

 or quite equal to the diameter of the test. In one specimen there are 

 7 or 8 coronal plates in a series, while in another there are 9 or 10, a 

 very large nmnber for thouarsii. The specimens from Espiritu Santo 

 bear a label reading " Enemies of pearl oyster at propagating plant." It 

 seems highly improbable that this can be a fact, though it may be the 

 impression of the pearl-shell growers. It would be interesting to know in 

 just what way the sea-urchin is supposed to injure the pearl shells. 



Espiritu Santo. 



San Francisquito Bay, east coast of Lower California. 



Six specimens. 



Centrostephanus coronatus (Verrill) 



Echinooliadema coronata Verrill, 1867, Trans. Connecticut Acad., I, p. 294. 

 Centrostephanus coronatus A. Agassiz, 1872, Illust. Cat. Mus. Comp. Zool. 

 VII, p. 97. 



There are five unusually large specimens at hand, 45 to 50 mm. h.d. * 

 thus twice as big as the largest in the earlier collection. The coloration 

 too indicates maturity, for the banded spines of the young are no longer 

 in evidence. Although all of the primaries have the tips broken off, 

 they are long enough to show the absence of bands ; they are deep claret 

 distally but browner basally. 



San Francisquito Bay, east coast of Lower California. 



Astropyga pulvinata (Lamarck) 



Cidarites pulvinata Lamarck, 1816, 'Anim. s. Vert.,' Ill, p. 59. 

 Astropyga pulvinata Agassiz and Desor, 1846, Ann. Sci. Nat., VI, p. 345. 



This interesting sea-urchin was not represented in the former collec- 

 tion, but there is a fine series at hand now, ranging from 15 to 95 mm. 

 in diameter. Unfortunately, they are not in the best of condition, the 

 small ones in particular being more or less damaged. On the larger 

 specimens the spines are mostly missing or broken. The most interesting 

 feature of these Astro pygas is the coloration. All specimens of pulvinata 

 which I have seen hitherto have had a dull greenish ground color, in 

 marked contrast to the deep red of A. radiata. The present specimens 

 however show that the ground color in pulvinata is deep, purplish red at 

 and above the ambitus and that the greenish color of dry museum mate- 



