346 AMERICAN JOURNAL 



Gould, as appears from Expl. Exped. Moll., p. 347) considered 

 the shells of the Northern and Southern oceans conspecific; 

 but they may pretty easily be separated. I have examined 

 more than a thousand from Vancouver, but none of them 

 have the horny aspect (common in Nacellse) which is generally 

 seen in Chilian specimens. In these, the young shell is more 

 swelling, which gives a slight excurvation to the profile of 

 the adult ; while the profile line of the posterior portion in S. 

 mitra is straight or even concave. Moreover, S. scurra is 

 crowded with minute, obsolete, radiating striao, crossed by 

 lines of growth, as described by Dr. Gould ; while S. mitra, 

 if sculptured at all, has the lines few, distant, and more raised.* 



An ordinary conical specimen measures: — 



long. 14, lat. 1-85, alt. 14. 

 A smaller, spreading " " 1-2, " 1*08, " -8. 



Surely, those who set the fashion in ladies' dress, must have 

 borrowed the outline of the most improved crinolines from 

 the spreading form of these little molluscs ; the conical form 

 representing the common kinds. But they should remember 

 that Scurrise, living where there is no fire and abundance of 

 water, are safe under a dome, which, inflated with air, made 

 of inflammable material, and near a fire, may consume, with 

 untold agony, the frame of the fashion-follower, who conceals 

 her form within a mere portion of it. 



As the sculpture described under P. conica, Gould, belongs 

 to S. scurra, Lesson, the rarer, sculptured form of S. mitra 

 may be described as var. tenuisculpta. 



Scurria mitra, t. striis, seu lirulis, valde distantibus, subex- 

 pressis, t. jun. intensioribus, plus minusve sculpta. 



* It is most probable tbat Dr. Gould had under bis eye some young spe- 

 cimens of S. scurra, along with the young of S. mitra, when he wrote the 

 diagnosis of Patella conica in Expl. Exped. Moll. The type specimen in 

 Mus. Smithsonian is undoubtedly S. mitra, jun. The specimens of the 

 United States Exploring Expedition shells were so sadly intermixed, and 

 the labels often so manifestly erroneous, that it is not wonderful if Dr. Gould 

 (and others who believed in them) should have occasionally erred. The 

 animal of Scurria scxirra, Lesson, ("embedded in the stalks of Fuci, Valpa- 

 raiso) is well described in Expl. Exped. Moll., pp.356, 357; but there is no 

 "genus Scurria, Eschscholtz," scurra being Lesson's species, and Scurria 

 Gray's genus. Dr. Gould also speaks (p. 356) of Acmcea persona, A. ra- 

 diata, and A. ancylus, Eschscholtz, as being varieties of '-Lottia scutum, 

 (Eschscholtz J D'Orbigny," the animal of which, as described by Couthuoy 

 from Valparaiso, is fringed with tine cirri. Now, A. scutum, Eschscholtz, is 

 a variety of A. patina, (as stated, indeed, by Dr. Gould himself at p. 352;) 

 and A- persona, with its varieties radiata and ancylus, form a very distinct 

 species ; all of them being from the Sitcha district. Nuttall's " monlicula' 1 '' 

 (=monticola) , a Californian shell =-pelta, var., is also quoted by Dr. Gould 

 among the Valparaiso limpets, p. 354. 



