BRACHIOPODA. 467 
TEREBRATULA PULVINATA (Gould). 
T. tenuis, lenticularis, orbiculato-trigona, allida, quincuncialiter punc- 
tata: valva minor convexa, latior quam longa, marginibus lateralibus 
rectis : valva major convexior, equé longa ac lata; apice rectangulari, 
truncato, lateribus incumbentibus ; foramine modico, circulari: apo- 
physis branchialis tenuissima, reflexa, incumbens. 
Terebratula pulvinata, Goutp; Proceed. Boston Soc. Nat. Hist., iii. 
347. Dec. 1850. Expedition Shells, 97. 
SHELL thin and delicate, orbiculate triangular, lenticular, yellowish- 
white, shining, and apparently smooth, but when examined by a mag- 
nifier the surface is found to be tessellated with elongated dots ar- 
rayed in quincunx, which seem to be specks of opaque white, rather 
than punctures. The valves are regnlarly convex, the large one most 
so, the smaller one about four-fifths the length of larger. broader than 
long, its anterior margin semicircular, its posterior sloping in a right line 
each way, forming a very obtuse angle; larger valve quadrant-shaped, 
right-angled at apex, which is truncated, and a very little curved; 
sides incumbent, forming large areas; ligament aperture small, cir- 
cular; internal apophysis delicate, tape-like, the two branches curving 
forwards and inwards, then recurved, uniting towards the beak. 
Diameters five-eighths of an inch; width one-fourth of an inch. 
Inhabits Puget Sound, Oregon. 
As in other species of this genus, individuals differ much in form, 
some being much more globose than others; and in some there is an 
angular gibbosity along the middle of the larger valve. It compares 
with T’. vitrea; has the same surface, colour, and general form, but in 
front is more rounded ; its posterior outline is more rectilinear ; the in- 
curved areas of the beak are much more flattened and broad; the 
aperture is larger, and with elevated walls. 
Figures 581, 581 a, sides of the shell ; 581 4, edge of the shell, in out- 
line; 581c, details of sculpture, enlarged; 581d, 581e, views of the 
apophysis. 
