2S 
SILURIAN 
LEPT.ENA HIMALENS1S. 
Plate 3, fig. 4. a-g. 
L. semiuncialis, quam semievali longior, valcle convexa7-9 costata 
profundeque striata, auriculis minoribus nec productis. Yalva minor 
profunde concava omnino striata, costula una in sulco quoque ; major 
ad natem solum striata, sed costulis binis. 
Rather more than half an inch wide, highly convex, semi¬ 
oval, but produced in front. All the surface, except the short 
pointed ears, ribbed by seven or nine obtuse ridges, the middle 
one largest, reaching from beak to front. The deeper valve 
(fig. 4) is very convex, the other (4 cl, e ) very concave. The 
surface of the former is coarsely striated near the beak only, 
and two fine parallel ribs run down each hollow. The coarse 
striae cover the concave valve (4 cl), and there is only one 
strong rib along each hollow in this valve. 
Lines of growth inconspicuous. Interiorly, the muscular 
impressions are deep (4 a ), the surface rough with tubercles; 
ovarian ridges obscure. 
The commonest of the Indian leptoenos, and a very elegant 
one. It is a good deal like the ribbed varieties of our British 
L . transversalis ; but the ribs are coarser, and the double rib 
between the furrows of the larger valve is an unusual character 
in this small but well-defined genus. 
Locality .—Chorhoti Pass (17,000 feet). (No. 1743.) 
L. HIMALENSIS. Far. TEXTILIS. 
Fig. 5. 
T cir, costulis 7 minus profundis, striis obscuris; lineis increment! 
conspicuis. 
Although this seems to have opposite characters to those of 
the species, I am persuaded it is but a variety, with shallower 
furrows, the outer two being obsolete. It has much less con¬ 
spicuous striae, but the lines of growth, which in the ordinary 
