OF SOUTHERN INDIA. 
19 
1867. The discrepancy hetweeii D’Orhigny’s first figure, in which thcantcro-, and 
postero-latcral ambulacra arc nearly of equal length, and his second figure in which 
the postero-latcrals ai’e scarcely more than two-fifths of the antero-laterals, is so 
enormous, tlmt nobody, judging from figures, could suspect them to represent one 
and the same species. However, as H’ Or higny ’ s de.scription better agrees with his 
figure in the Pal. Francaisc, and as it is very improbable tliat the Uemiastcr has the 
anterior and posterior ambulacra equal in length, I give a slightly altered transcript 
of D’Orbigny’s description and the figures which accompany it. I would only 
observe, that there is an ap])arcnt inconsistence between the figures 1 c and 1 e, as 
I’cgards the posterior extension of the fasciole. 
Of course, with the imccrtainty before us it is impossible to compare D’Orbigny’s 
species with any of the species previously described. The figure in the Astrolabe 
exhibits considerable relation to Hemiaster vicinus, except in being anteriorly 
narrower ; but that in the Palcontologie differs from all by the very small size of 
the postero-lateral ambulacra ; the form and general character of the test is, how- 
ever, not unlike some specimens of II. cristatm. 
Dimensions. — Greatest width 29 mm., length almost exactly the same, 
height 0'71 of the greatest width. Test hexagonal, scarcely* broader than long, 
with rounded angles at the periphery, narrowed at the anterior and posterior 
extremities, the latter of which is truncated, its height is 0'71 of the width, and 
its large transverse diameter lies at the middle, the fiattened end being surrounded by 
somewhat prominent angles. Uirper side convex, rounded in front, gradually curv- 
ing upwards to the apex which lies somewhat in front of the centre; the median intcr- 
ambulacral space lying between the apex and the anal end is also curved, being 
the highest part of the test ; the anal end itself is obliquely truncate. The rounded 
circumference is most convex near the base. Anterior ambulacral furrow rather 
wide and deep ; continuing from the mouth to the apex. Mouth transverse, placed 
near the anterior end. Anus longitudinally oval, placed at the rqipor end of the 
flattened area. Anterior ambulacrum straight, the pores in each pair being oval, 
oblique, and separated by a small tubercle. Lateral ambulacra rather large, deep, 
very unequal, the anterior being doublet the length of the posterior, very divergent 
(under an angle of 128 degi’ccs) and slightly curved baelcAvards; the poriferous 
zones are broader than the interspace separating them, and the pores themselves 
are transversely elongated. Fasciole in general aspect triangular, narrowly 
truncate posteriorly. Tubercles numerous, considerably larger below than alwve. 
The form of this species might lead to mistaking it for U. rana, but it is readily 
distinguished by its more marked hexagonal shape, and is veiy much elevated poste- 
riorly, by the apex being antero-central, the anal area much sloping, and the lateral 
ambulacra very unequal. 
* D'Oi'Ijif'uy writes, “plus largo quo longue.” 
t According to the figure the posterior ambulacra are scarcely more than two-fifths of the length of the anterior ; 
and the3^ certainly exceed one-half. 
P 
( 89 ) 
