200 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Sphenia fragilis Carpenter, 1857. 
Masatlan Catalogue, p. 24, No. 30. 
S. animali in cryptis latibulante, ergo varie distorto; testa parva, tenui, 
subnacrea, vix rugose striata; epidermide fusco-virente copiose induta, 
rugarum increscentium concentricarum plena, postice in siphone longa 
porrecta; parte postica plus minusve subcarinata; valva sinistra dente 
ligamentum ferente, plus minusve sett prolongata seu extante; dextra alveo 
conveniente, nonnumquam denticulo subticulo subextante; impressionibus 
muscularibus subrotundatis, sinu pallii lato, rotundato, haud alto. (Car¬ 
penter.) 
Shell somewhat elongate, inequilateral, opaque, but not solid, inequi- 
valve; the left valve being smaller and somewhat flatter; the epidermis is 
of a dull yellow, closely attached, beneath which the surface is almost 
smooth, or may be wrinkled with concentric and rather distant wrinkles of 
growth. The ventral margin more or less straight, and usually ascends a 
little behind. The right umbo projects somewhat above the dorsal line; 
beaks acute, and incurved. There is an umbonal ridge in each valve. 
Interior white. Hinge with an erect tooth in left valve and a corresponding 
tooth-receptacle in the right valve. This is, a nestler and is irregular in 
form. Many species might lie made out of the extreme forms. Some 
shapes are very short, inflated and gibbous, resembling Corbula, or some¬ 
times Near a. The ligamental plate becomes narrow, projecting and sinu- 
ated, more like the tooth of My a. These varieties are seen in the young as 
much as in the adult shells. It is found living in the burrows of worms 
and mollusks, and in the kelp roots. Length, 11; height, 9 mm. 
Type in British, Museum. Type locality, Mazatlan, Mexico. 
Range. Vancouver Island, British Columbia, to Mazatlan, Mexico. 
Sphenia ovoidea Carpenter, 1865. 
Suppl. Rep. Brit. Assoc., p. 637. Proc. Acad. Nat. Sci. Phila., p. 54, 1865. 
S. t. parva, albida, ovoidea; epidermide cinerea, parum rugosa, induta; 
marginibus, antico et ventrali regulariter excurvatis; dorsalibus rectis ad 
angulum circiter 150°; parte postica augustiore, obtuse angulata, parum 
truncata; umbonibus prominentibus, circiter ad duas inter quinque partes 
totius longitudinis sitis; intus, lamina cartilaginea lata, parum extante; 
sinu pallii ovali, usque ad medium interstitii porrecto. Long., .3; lat., .16; 
alt., .09, poll. (Carpenter.) 
Siphonal area small; front excurved; mantle bend large. (Carpenter.) 
Type locality, Puget Sound. 
Range. Aleutian Islands to Puget Sound. 
