ASTHENOSOMA HYSTEIX. 29 
3.25 mm., the abactinal 5.50 mm., and the actinal 5 mm. ; the height of the 
test was 9 mm. ; with nine and ten plates in the interambulaeral areas. 
In a specimen measuring 5 mm. in diameter, the anal system measured 
1:25 ram., the abactinal 3 mm., and the actmal 2 mm. ; with seven and eight 
plates in the interambulaeral areas. 
Asthenosoma hystrix A. Ao. 
Asthenosoma Reynoldsii A. Ag. Bull. M. C. Z., VIII., No. 2, p. 75, 1880. 
Montserrat, Santa Cruz, Barbados. 103-373 fathoms. 
PL XIII., PI. XIV. 
The differences which I noticed (Preliminary Report on the Blake Echini, 
Bull. M. C. Z., VIII., No. 2, p. 75) in some of the larger specimens of Asthe- 
nosoma collected by the Blalvc, seemed to be of sufficient importance to 
separate them from A. hystrlv under the name of A. Riynohhii. A more 
careful examination of the large series of Asthenosoma collected by the 
Blake has satisfied me that the differences, striking as they appear at 
first sight, are merely due to age, and that what I had called A. Iif//nol(lsii 
in the Preliminary Report are only large specimens of A. hystrix. Spe- 
cimens measuring about 125 mm. in diameter are figured by Thomson in 
the Porcupine Echini, Pis. LXIV., LXV. ; and by me in PI. II. of the Hassler 
Echini (TO mm. in diameter). I have figured on Pis. XIII. and XIV. two 
specimens 165 mm. in diameter, showing the features characteristic of the 
largest A. Reijnoldsii collected, which measured about 170 mm. in diameter. 
In the smaller specimens, less than 70 mm. in diameter, the coronal plates 
of both areas are relatively narrower than in larger specimens, and while 
the general arrangement of the primary tubercles does not differ greatly in 
specimens of different sizes between 50 and 120 mm. in diameter, in the 
ambulacral areas, or in the two areas above the ambitus, yet there are very 
considerable differences to be noticed in the interambulaeral areas on the ac- 
tinal side. We find in larger specimens a third, and sometimes even a fourth, 
vertical row of primai-y tubercles extending from near the actinostome to 
above the ambitus. Compare PL XIV. Fig. 4, with the figures of Thomson 
in the Porcupine Echini, and those of the Hassler Echini quoted above. 
The smaller specimens less than 70 mm. in diameter are usually of a 
brilliant claretrcolor, but often of a light pink color with only darker 
patches of deep claret on the actinal side ; we find larger specimens 
