a) Res SHELLS OF SAN PEDRO BAY—WILLIAMSON. 
full, with 11 to 13 narrow rounded ribs extending nearly from suture to 
suture; spiral sculpture of numerous flattened strap-like cinguli sepa- 
rated by subequal channeled shallow interspaces; epidermis thin and 
yellowish; color of shell pale straw color with a brownish base and a 
brown band extending from the periphery half-way back to the suture; 
aperture about equal to the spire, the penultimate rib behind it a little 
swollen; pillar slender, polished white with little callus; canal wide, 
short, recurved; outer lip simple, slightly reflected; not lirate inside. 
Longitude of shell, 14.0; of aperture, 7.7; maximum diameter of shell, 
8.0 millimeters. 
Habitat : Dredged by the U.S. Fish Commission at various places 
off the coast from Point Sur to San Diego, and in the Santa Barbara 
channel in depths varying from 124 fathoms at the south to 298 fath- 
oms at the north, over a sandy or muddy bottom. 
The operculum is brownish and resembles that of A. versicolor Dall. 
The brown coloration, though generally disposed in bands as described, 
is variable, and occasionally appears in a zigzag pattern on the pale 
ground, or generally suffused over the surface, or even maculated, as 
in Nitidella, The apex when perfect is probably moderately acute, but 
is more or less eroded on all the specimens. (W. H. D.) 
Amphissa undata Cpr. PI. xx, fig. 8. 
Plentiful in 16 fathoms mud, off Catalina Island. This was described 
by Carpenter as Amycla undata and for some time confounded by him 
with A. versicolor. The fineseries of A. corrugata Rve., undata, versicolor, 
ete., now in the National Museum, enable the species to be distinctly 
differentiated. (W. H. D.) 
Family MURICID 5. 
Genus PURPURA Brug. 
Purpura lima Mart. var. emarginata Desh. 
This shell, and two or three varieties of P. lima, have been reported 
from Laguna Beach, Orange County. I have not seen, nor heard of, a 
recent Purpura in Los Angeles County. That it should be found liv- 
ing in the county south of us andin Ventura County north of us, yet not 
collected here, is certainly noticeable. 
Genus MONOCEROS Lam. (dAcanthina F. de Waldheim). 
Monoceros engonatum Conr. 
Plentiful on the rocks at Rattlesnake Island. 
Monoceros engonatum var. spiratum Blainy. 
A few with the type. 
