OF CONCHOLOGY. 251 



muzzle short, transversely oval ; frill very niirrow, granulose ; 

 disk radiately granulose ; mouth semicircular ; gill triangular, 

 short, stout, small and wide. Anal papilla large, cylindrical; 

 infra-anal smaller, bifid. Renal orifice to the left of anal tuber- 

 cle very small, subcircular. Faeces expelled in sausage-shaped 

 pellets. Formula, 9 



^ ' 1C2— 1-1— 2)1- 



There is a small smooth variety of this species, with tesselated 

 yellowish brown markings and a dark apex, which seems (with- 

 out a connecting series) very far removed from the typical rib- 

 bed form. 



The home of this species is in the Vancouver district. A very 

 few were obtained at Sitka, and it may be considered pretty 

 certain that Cape Spencer is its northern limit ; it is plenty as 

 far south as Monterey, and extends to San Diego. Habitat be- 

 tween tide marks. 



COLLISELLA SPECTRUM, Rve. sp. Plate 14, fig. 10. 



Patella spectrum, Rve., Conch. Icon. pi. xxix, f. 76 a, b. 

 Lottia seabra^ Gld. (pars). 



Soft parts : foot oval, sides whitish, smooth, darker toward 

 the edge, sprinkled with black dots and streaks. Mantle whitish 

 with dark patches, and irregulal* prolongations corresponding to 

 the rays of color and ribs of the shell, edge smooth, ciliated. 

 Gill small, short, triangular, thick, sharply pointed with a 

 strongly crenate border on the left side ; head small, anteriorly 

 blackish, behind white ; tentacles short, stout, pointed, tips black- 

 ish, bases nearly white ; muzzle small, produced ; disk striate ; 

 mouth. rounded ; frill granulose, narrow ; hood rather large; renal 

 orifice not detected ; anal papilla small, conical, pointing 

 to the right ; infra-anal bifid, larger than and to the right of the 

 anal tubercle. Formula as in the hist. 



This is a more southern species than most of those previously 

 mentioned. The northern limit of its authentic habitat is Bo- 

 dega Bay (Stearns), but it extends southward into Lower Califor- 

 nia, and is suffioiontly common at Black Point, San Francisco 

 Bay, and Monterey. It is a very sedentary species, invariably 

 assuming the form of the rough crystalline surface of the rocks 

 upon which it lives. It is also more confined in its station, keep- 

 ing nearer low water mark than most of the other species. 



COLLISELLA SCABRA, Rvc. Plate 14, fig. 12, 12a. 



Patella scahra, Rve., Conch. Icon. pi. xxxvii, f. 119 a, b, (not 

 scabra, Gld.) 



Soft parts : foot oval, sole light yellowish or ashy, sides almost 



