ASPIDODIADEMA JACOBYI. 27 
are less numerous in this species than in A. microiuberciiMmn ; it also differs 
from it in having three or four ainhulacral plates (in the median region of 
the test) to each interambulacral plate, while there are no less than five or 
six in A. microtubercidahini. The proportions of the spines to the test and the 
general appearance recalls more A. loimiuK while the colorino- when alive 
is more that of A. microtubcrculatuni, with a light violet or grayish pink test 
and the spines of the same tint but lighter. The primary spines are slender, 
as in A. tonsiim, but they are more curved than in that species. The abac- 
tinal part of the test of A. aufilianim is more flattened (Echinostrephus-like) 
than is the case in either of the species collected by the Challenger. 
The largest specimens of this species collected did not measure more than 
13 mm. in diametei-. 
In a specimen measuring 7.5 mm. in diameter, the anal system measured 
3 nun., the abactinal 5 mm., and the actinal 3.75 nun. in diameter; the height 
of the test measured 3.75 mm. 
In a specimen measuring 11 mm. in diameter, the anal system measured 
3.6 mm., the abactinal 6.50 mm., and the actinal 5.50 mm. in diameter; the 
height of the test measured 6 mm. 
o 
* Aspidodiadema Jacobyi A. Ao. 
Aspidodiadema Jacobyi A. Ao. Bull. M. C. Z., VIII., No. 2, p. 74. LS80. 
Caviuan Brae, Lesser Antilles. 95 to 297 fathoms. 
P/. IX''. 
The largest specimen of this species collected by the BlalvC measured 
32 mm. in diameter. As in A. v/icrotuberculafniii, the primary spines are 
rather stout, curved, and comparatively short, they are somewhat more 
closely packed than in that species, from the greater number of primaries in 
the interambulacral areas, a specimen measuring 28 mm. in diameter having 
11:12 primary tubercles. The miliaries are more distant than in that spe- 
cies, forming a belt of distinct irregularly arranged miliaries in the median 
interambulacral space. We find in this species, as in A. iomiini, large pri- 
mary ambulacral tubercles, extending nearly to the al^actinal system ; all 
the largest tubercles being placed above the median line of the test, and 
gradually increasing in size from that point to the abactinal region, much 
as they do in Echinostrephus. 
There are not more than three ambulacral plates to each interambulacral 
plate. The miliaries extend in horizontal lines between the pores, and form 
