I'i 
62 LINOPNEUSTES LONGISPIXUS. 
lovvish gra^- primary spines of the abactinal surface ; ia 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., Vlll., No. 2, p. 82, 1880. 
Eupatagus longispinus A. Ag. Bull. M. C. Z., V., No. 9, p. 191, 1878. 
Oil' Havana, Le.sser Antilles. 38-2r)0 fathoms. 
PL XIX. Fig. 1 (upper fig.) ; PI XX. 
This species was first noticed as Eupatagus longispinus, from a niimljer 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 Murrugi. 
The test of this species is depressed, apex slightly anterior. It holds in 
the genus Linopneustes the same relation to L. Murrayi wdiich Pidcopnmstcs 
hgstrix holds to P. cristaius. Both P. cristatus and L. Murragi are covered on 
the abactinal side with a close tuberculation, carrying comparatively small, 
stout, slender primary spines ; while P. hgstrix 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 sjoecimens I have examined, varying from 65 to 110 ram. 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 arabital edge (PI. XX. Fig. 8) of the test, passing at the posterior 
extremity close to the upper part of the anal sj'stcm. 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 folloAvs 
the same course close to the ambitus, but its posterior extremity passes 
under the anal system. Desor lias 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 recent 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 L. Murragi. The anal system is also 
