62 LINOPNEUSTES LONGISPINUS. 



Iowish gray primary spines of the abactinal surface ; in others, the test and 

 spines are of a greenish purple, the most common coloring of the test being 

 a light Indian-red with primary spines of the same tint. 



* Linopneustes longispinus A. Ag. 



Linopneustes longispinus, A. Ag. Bull. M. C. Z., VIII., No. 2, p. 82, 1880. 

 Eupatagus longispinus A. Ac. Bull. M. C. Z.. V.. No. 9, p. 191, 1878. 

 Oil" Havana. Lesser Antilles. 38-250 fathoms. 



PL XJX. Fig. 1 (upper fig.); PI. XX. 



This species was first noticed as Eupatagus longispinus, from a number of 

 somewhat imperfect fragments, showing this large Spatangoid to be related 

 to Eupatagus, Platybrissus, and Paleopneustes. A number of specimens since 

 collected off the West India Islands show that it is closely allied to Lino- 

 pneustes Mwrrayi. 



The test of this species is depressed, apex slightly anterior. It holds in 

 the genus Linopneustes the same relation to L. Murrayi which Paleopneustes 

 hysirix holds to P. cristaius. Both P. cristatus and L. Murrayi are covered on 

 the abactinal side with a close tuberculatum, carrying comparatively small. 

 stout, slender primary spines ; while /'. hystrix and L. longispinus both are 

 characterized by the few and comparatively large primary tubercles seated 

 on the plates of the interambulacral areas of the abactinal surface. In 

 all the specimens I have examined, varying from 65 to 110 mm. in length, 

 the marginal fasciole ( PI. XIX. Fig. 1) is most prominent, forming a nar- 

 row band carrying minute dark-colored miliary spines all round the abac- 

 tinal ambital edge (PI. XX. Fig. S) of the test, passing at the posterior 

 extremity close to the upper part of the anal system. In this respect the 

 course of the fasciole of this species of the genus Linopneustes differs strik- 

 ingly from the tertiary Pericosmus, in which the marginal fasciole follows 

 the same course close to the ambitus, but its posterior extremity passes 

 under the anal system. Desor has called attention to the variability of 

 this fasciole, which in the fossil species of the genus Pericosmus appears to 

 be often as ill defined and as variable as in the recenl species of Lino- 

 pneustes. 



The subanal fasciole of Linopneustes longispinus | PI. XX. Fig. 8) is trans- 

 versely elliptical, irregularly hexagonal with rounded corners, and narrower 

 than the corresponding fasciole of 7.. Murrayi. The anal system is also 



