CLASS BRACHIOPODA 
227 
crenulatis, haud undatis; intus amen to majore, bisinuato, dorsaliter haud 
continuo, calcaribus duobus munito. Long., .6; lat., .5; alt., .3 poll. (Car¬ 
penter.) 
Shell ovate, longer than wide; valves almost equally convex, rounded 
laterally and in front; lateral sides of the umbo strongly auricular, espe¬ 
cially in young and middle-aged specimens. Ventral valve evenly convex, 
but sometimes very slightly depressed anteriorly; beaks short, obliquely 
truncated by a rather large, incomplete foramen, margined anteriorly by 
the umbo of the dorsal valve and by two small lateral deltidia. Surface 
of valves marked with numerous radiating, delicate riblets, simple and 
stronger at their origin, but rapidly augmenting in number from bifurca¬ 
tion and by the interpolation of shorter riblets between the longer ones. 
Valves crossed with concentric raised stride, loop short and simple, the 
crura disunited in the young, annelliform in the more advanced age. 
Colour light yellowish white. (Davidson.) 
Type in British Museum? Type locality, Monterey, California. 
Range. Unalaska, Kodiak Island, Forrester Island, Alaska; Gulf of 
Georgia; San Diego, California; Cape San Lucas, Lower California. 
Genus TEREBRATALIA Beecher, 1893. 
Shell transversely ovate, thin, rugose, with a concave impression in 
the middle; beaks rather short; marginal line somewhat flexuous, slightly 
sinuated in front; foramen very large, incomplete; deltidia small, widely 
divided; margin of the valves entire. 
Type. Terebratula transversa Sowerby. 
Distribution. West coast of America, Japan, China, Atlantic coast 
of America. 
Terebratalia transversa Sowerby, 1846. 
Plate 16, figs. 1, 2, 3. 
Proc. Zool. Soc., 1846, p. 94. 
Ter. testa transversim subovata, tenui, rudi, glabra, pallescente; linea 
marginali subflexuosa, antice subsinuata; foramine maximo, incomplete; 
area cardinali magna, planata; deltidiis parvis, longe discretis; carina 
dorsali inconspicua, rotundata; valva ventrali transversim oblonga, antice 
rotundata, postice in angulo obtusissimo desinente; sulco mediano sub- 
inconspicuo, rotundato; margine valvarum integro. (Sowerby.) 
Shell very variable in shape, usually quadrispherically transverse, wider 
than long, broadest posteriorly or near the hinge line, which is very 
obtusely angular, almost straight, very little shorter than the breadth of 
the shell; marginal line flexuous and situated in front. Dorsal valve 
moderately convex, channelled longitudinally along the middle by a con¬ 
cave depression or sinus. Ventral valve much deeper than the dorsal one, 
