OF CONCHOLOGY. 341 



lirulis quibusdam majorilus, valde nodosis ; imtus albida, ni- 

 tida; limbo lato nigro, seu rarius tesselato ; spectro saepius 

 fusco maculato. 



It is probably the Acmsea patina of the Mazatlan Catalogue, 

 sp. 265, but the specimens were too much worn outside to de- 

 cide with confidence. 



Habitat. — San Pedro, Cooper, Palmer; Sta. Cruz, Rowell; 

 Monterey, Rich; Mazatlan, Reigen. 



Ordinary collections ot limpets from the coast may generally 

 be grouped under the above five species ; the three first only 

 being Northern. A few individuals, however, are (rarely) 

 met with, which must continue to perplex malacologists till 

 more specimens have been compared, and their animals ex- 

 amined. They belong to two distinct forms. The first is 



Acmjea Asmi, Middendor£ 



This is easily recognized by its small size, very conical 

 shape, uniform dark color, and great solidity. It is generally 

 rounder than N<wella incessa; and the latter has a horny aspect, 

 and is moderately thin. Among all the myriads of limpets 

 which I have handled, I have never seen more than about 6 

 specimens of A. Asmi. I am inclined to regard it as a stunted 

 variety of one of the other species, probably pelta though it 

 may be a cross between that species and patina, var. Cuming ii. 

 This view is confirmed by one of Dr. Cooper's specimens, in 

 which the adult shell is a normal pelta, while the young por- 

 tion wo aid have made an excellent Asmi, if detached from the 

 rest. 



Acm^a (?var.) rosacea, Carpenter. 

 Brit. Assoc. Rep. 1863, p. 650, no 248. 

 =A. pileolus, Mus. Cum.: fnon Middendorf. 



A. t. parva, conica, tenui, lasvi ; t. jun. pallide rosacea,, ele- 

 gantissime maculis albis et fuscis subradiatim sparsis; t. adulta 

 strigis fusco-rosaceis et albidis pictu,; apice elevato, parum 

 antico; intus rosacea. Long - 2, lat. '16, alt. "08 poll. 



Habitat. — S. Diego, Monterey, Cooper. 



Specimens of this species are named "pileolus, Midd.," in 

 Mus. Cuming, and are said to have been received by Mr. 

 Damon from Middendorff himself. But there surely must be 

 some mistake, as the following is the author's diagnosis, in his 



