342 AMERICAN JOURNAL 



Beitriige, Vol. II., p. 38, (and plate I., fig. 4):— "T. minuta, 

 leviuscula, elliptica, elevata, fornicato-conica, vertice subantico; 

 extus, vestita epidermide fusca, sub microscopio irregulariter 

 rugosa, centro sagpe multum erosa, et inde calcarea, albida : 

 intus nitida, ex livido flavicans, margine fusco, et macula 

 eadem centrali. Long. 8, lat.6, alt. 4 mill. Div. ant. 55°, post. 30°. 

 In my specimen, the central and greater part of the exterior is 

 eroded and without epidermis, so that the latter only sur- 

 rounds the shell with a brown marginal band. Though inter- 

 nally bright, the brown has externally a faint water -colored 

 shade. The shell is arched in each direction. A color va- 

 riety has the margin painted with about 20 white spots, ar- 

 ranged radiatingly inside and out. Habitat. — Sitcha." 



I hardly know how my rosacea can be affiliated to the 

 above ; and believe that Middendorff must have had under 

 his eye, when writing, specimens of pclta, jun., of which there 

 are many varieties in the Northern seas. 



Dr. Cooper's young specimen from S. Diego was perfectly 

 fresh, though completely encrusted. On removing the nulli- 

 pore, it appears quite smooth; in other respects exactly resem- 

 bling the common Southern form of A. virginea, as seen in 

 the shell sand from the Channel Islands. The larger specimen 

 from Monterey had lain dead long enough for annelids to 

 build their houses inside; but, except in the absence of strioe, 

 which are rarely seen in dead British specimens, it exactly re- 

 sembles one of the shells sent by Mr. Bean as A. virginea 

 from Scarborough. It can hardly be supposed, however, that 

 the species are identical. It is distinguished from A. patina, 

 jun., a rare variety of which has a pinkish tinge, by the ab- 

 sence of striae, the very thin texture, and the regularly conical 

 growth. A more numerous series of shells of this form will 

 be awaited with interest. Some specimens, almost exactly 

 corresponding with the young shell from S, Diego, but striated, 

 were collected by Col. Jewett. They were marked "Panama," 

 but I strongly suspect that they were West Indian. 



Genus LOTTIA. 



=Lottia, Gray, auct. jwrs : maxima pars=Acm8ea, Esch. 



Animal, pallii margine intus papillis lamellaribus, circa 

 dorsum lateraque instructo, antice interrupts : pede elongato, 

 ovali, planato; branchia minima. (Alcock.) 



Testa Acmsea similis. 



