476 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Acrotreta taconica (Walcott). 
Linnarssonella taconica Walcott, C. D., Amer. Journ. Sci., ser. 3, vol. .34, 
p. 189-190, pi. 1, figs. 18, 18a-d, 1887. 
Our specimens are slightly larger than those from Washington 
County, New York, but otherwise agree with the t3'pe material 
in all respects. These brachiopods are the only fossils in this 
collection that show any trace of a former chitinous shell. The 
largest, a brachial valve, is 5 mm. wide and 4.5 mm. long. 
HyoUthes americanus Billings. 
Grabau, 1900, p. G47. 
HyoUthes impar Ford. 
Grabau, 1900, p. 652. 
The two species named above are represented in our collection 
by one specimen each. 
HyoUthes princeps Billings. 
Grabau, 1900, p. 643. 
This species is very common. Our largest specimen, incom- 
plete at both ends, is 40 mm. long, 14 mm. wide at the larger and 
9.5 mm. wide at the smaller end. 
Orthotheca cylindrica Grabau. 
Grabau, 1900, p. 654. 
Two specimens. The longest is 5.5 mm. long and 0.3 mm. thick. 
This is smaller than most of the individuals of this species that 
have been found around Boston, but it is probably immature. 
Salterella sp. 
This is a gently curv^ed form, 12 mm. long, 3 mm. in diameter 
at the larger end; its proximal end is hemispherical. Several 
septa are shown, the bases of which are not to be seen in our 
specimen because it is broken longitudinally not quite through 
the middle. It appears as if the rounded proximal end might 
represent the position of one of the septa rather than the original 
terminus of the shell. 
Eodiscus belUmarginatus (Shaler and Foerste). 
Grabau, 1900, p. 670. Raymond, 1913, p. 103. 
Our material includes two pygidia of this species. One of these 
was found in a remarkably fine state of preservation and showed 
