BRACIIIOl’ODA. 
39 
L. trachealis, but there are no indications of it in our speci¬ 
mens which may, however, have been young* shells. 
Locality .—Upper llimkin; also Milam. (No. 931.) 
STROPHOMENA LINEATISSIMA. 
Plate 3, fig. 14. 
S. undalis, late semiovalis, auriculis acutis, margini lato deflexo 
plicoso, disco piano. Strife radialcs tenuissimse, majoribns crebris in- 
terspersis minutisque transversis ornatae. Superficies lineis incrementi 
rugosa, ad marginem etiam antiquata. 
One inch wide, seven lines long. Half a broad oval, with 
pointed ears ; the margin turned abruptly down and longitu¬ 
dinally folded in the ventral valve, and bent backward in the 
dorsal valve; the disk nearly flat, with no concentric rugae, 
but with strong close concentric ridges and lines of growth. 
The radiating striae are very fine, close, and unequal in size; 
the larger ones are numerous, and interlined with very fine 
thread-like striae, all rough with minute transverse lines in 
addition to the larger lines of growth. 
Locality. —Damchen; Chorhoti ; Kalajowar. (Nos. 1757 
1765, 1766.) 
ORTHIS THAKIL. 
Plate 4, figs. 8-13. 
O. fere uncialis, costata, valva dorsali valde convexa, altera plana. 
Costae rotundse 18-20 (in nonnullis varietatibus angulares numerosae 
2-3-4 fidse). Sinus dorsalis medianus nunc distinctus, nunc obscurus. 
A conspicuous shell, about an inch broad, and eight lines 
long, with fourteen strong rounded ribs (in the typical variety, 
and eighteen or twenty in the extreme varieties. These ribs 
are trifid or quadrifid for their lower half in the coarse ribbed 
forms, and divide into numerous fasciculate ribs in the finer- 
ribbed varieties. 
The dorsal valve is highly convex, with a very slight 
median depression. The ventral valve fiat or slightly concave, 
