64 
PALEONTOLOGY OF NEW YORK. 
umhonata, possesses a peculiar loop connecting the spirals, and has, therefore, 
upon this character based a distinct genus. The situation of this organ, the 
Fig. 46. Fig. 47. 
The primary lamellie aad loop of Hindella umhonata. Hillings, (c.) 
loop, is very far forward, and its inclination to the primary lamellae is extremely 
oblique, the lateral processes or branches being directed backward in a low up¬ 
ward curve, uniting to form a short, straight, undivided stem. The posterior 
extremity of the entire process rarely extends back of the middle of the first 
lamellae and does not rise to the center of the bases of the spirals. 
The form of this loop is somewhat similar to that occurring in the genera, 
Whitfieldella, Hyattella, Nucleospira, etc., but its anterior position on the 
primary lamellae and its very depressed form are without parallel among these 
brachiopods with everted spirals. 
Congeneric with Hindella umbonata is Billings’ Athyris Prinstana, from the same 
locality; a shorter and more rotund form than H. umbonata, but probably no 
Fig. 48. Fig. 49. Fig. 50. Fig. 51. 
Consecutive transverse sections of the umbonal region of Hindella umhonata, Billings. 
Fig. 48. Section just below apex of pedicle-valve, showing the grooved pedicle-passage. 
Fig. 49. Section at apex of brachial valve, showing the dental lamellae. 
Fig. 50. A deeper section, exhibiting the teeth, and the remnants of the dental lamellie bounding the muscular area. 
Fig. 61. Section showing the lateral elements of the hinge-plate. (c.) 
Some additional characters of these shells may be added ; 
The outline is subcircular or elongate-ovate ; the valves convex; the pedicle- 
valve being gibbous in the umbonal region. The hinge-line is very short but 
the cardinal slopes are frequently long and transverse, which, with the fulness of 
