Tkopidolkptus Fauna ai Canam)AI(;ua Lakk, \. \. i;}8 



Strice. — A specimen 1.S7 mm. long has seven striiv; on the ventral 

 valve. The median one is stronger and a little longer than ihe others. 

 A specimen 3.4 mm. long has 15 stride and the largest specimen has 

 the same number on the ventral valve and 14 on the dorsal. A smaller 

 specimen, 3.46 mm. long, has 18 striae on the dorsal valve and 

 another, 5.5 mm. long has 16 striai on one valve and 17 on the other. 



Fig. 32. 'I'ligeria lepiJn Hall ; series showint^ the t^rowth of the deliidial plates 

 and the encroachment of the pedicle upon the ventral beak. X '^• 



Deltidial Plates. — None of the specimens less than 3 mm. long, 

 show any traces of deltidial plates. The specimen 3.4 mm. long 

 shows a very narrow scalene triangle on each side of the delthyrium. 

 In the specimen 5.5 mm. long these triangles have become wider at the 

 base, almost imiting. The apex of the ventral beak is encroached 

 upon, thus enlarging the opening posteriorly. In the largest speci- 

 men the deltidial plates are still wider at their lower ends and are 

 imited for a short distance. The pedicle has encroached still further 

 upon the ventral beak, forming a large oval opening. 



Sinus. — The sinus in the dorsal valve is still sharp and distinct in 

 a si)ecimen about 3.5 mm. long, but, on the larger specimens, it is 

 hardly perceptible. 



Eunella lincklaeni Hall. 



Hall, Pal. X. v., IV, 1867, p. 397, pi. 60, figs. 49-65. 



Of this species there are about forty whole specimens retaining both 

 valves and nearly as many separate valves. The smallest specimen is 

 1. 17 mm. long and .84 mm. wide; the largest 19 mm. long and 17 

 mm. wide. So perfect is the preservation that in many cases a large 

 part of the delicate loop which supported the brachia is preserved 

 and, in at least one case, the loop is entire and as well shown as in 

 the most perfect recent brachiopods of this type. 



Description of Smallest Shell. — No stages earlier than that repre- 

 sented by the smallest shell in the collection could be made out. At 

 that stage the shell is about three- fourths as wide as long, and the two 



