168 



WEST COAST SHELLS 



Fig. 156 (*) 



is another of the three- 

 winged California forms, 

 and is named Murex petri^ 

 DalL, St. Peter's Murex. It 

 was obtained by Mr. and 

 Mrs. Oldroyd from rather 

 deep water at San Pedro, 

 so it doubtless takes its 

 name from that ot the lo- 

 cality where it was ob- 

 tained, Pedro's, or Peter's, 

 Bay. The color of the shell 

 is yellow-brown, mottled 

 with lighter spots. Its 

 length is 65 millimeters. 

 This shell is rough all over, while the last one is 

 smooth between the varices. 



Murex trialatus^ Sby., the Three-winged Murex, 

 has a much smaller shell, with dark brown and white 

 color bands. The shoulder of the whorls is exca- 

 vated, the three varices thick and rounded, and the 

 frills sometimes beautifully recurved. A fine speci- 

 men was dredged by Mr. H. N. Lowe, off San 

 Pedro, in ten fathoms of water. 



Murex circumtextus^ Stearns, the Cir- 

 cled Murex, Figure 157 (Ocinebra cir- 

 cumtexta)^ has a rather heavy shell, 

 many low varices, and many very deep 

 and distinct spiral grooves which give the 

 outer lip a scalloped appearance. It is 

 of a reddish color within, but externally 

 it is whitish, with brown spots arranged in a spiral 



Fig. 157 



