226 CALIFOKNIA ACADEMY OF SCIENCES. 



209. Fusus robustus Trash. 



Fiisiis robustus Trask, Proc. Cal. Acad. Sci., Vol. I, 1S55, j). 41. Cooi'kr, jtli Ann. R(.-|)i. Cal. .St. 



Min., 1S88, p. 241. 

 Fusus kobelii {no\. of Dall), of Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 240 (in part). 



Sliell of medium size, elonj;;atc-fusiforni, thick; whorls about si.\, convex, crossed by eii;ht 

 or nine prominent rounded ridges which are most prominent on angle of whorl (these ridges are 

 sometimes obsolete on the anterior part of the body-whorl); spiral sculpture consists of four to six 

 prominent raised lines, with sometimes smaller lines intercalated; suture ajiprcssed, deep, distinct; 

 aperture pyriform; outer lip smooth on inner edge, but with numerous sjiiral ritlges further in; inner 

 lip smooth; columella spirally ridged externally; canal rather short, narrow. 



Dimensions. — Long. 34 mm.; lat. 14 mm.; body-whorl 22.5 mm.; aperture, including canal, 

 17 mm.; canal 5 mm.; defl. 40 degrees. 



Distinguisliable from /•'. ritgosus by smaller size, heavier shell, lack of promi- 

 nent angular appearance of whorls and ridges near posterior suture, less number of 

 whorls and relatively shorter canal. Upon examining a large series of this species 

 and of /•'. ni//usnf< the writer has no hesitancy in separating tiicsc two forms of Trask's. 

 Distinguishable from /'. kohiti by deeper appressed suture, stronger, revolving ridges, 

 narrower form, and lack of wavy sutural band on posterior edge of whorl. F. robustus 

 is probably a precursor of F. kobelti. This species has been identified as F. amhustus 

 by many West Coast conchologists, including Cooper and perha2)S Carpenter. Speci- 

 mens identified by Dr. Dall. 



Found only in the upper San Pedro series; rather common at Old San Pedro. 

 Found also in the Pleistocene at the bath-house, Santa Barbara. 



Living. — Santa Barbara to San Diego (California State Museum). 



Pleistocene. — Santa Barbara (Cooper; Arnold): San Pedro (Trask; Arnold). 



210. Fusus rugosus Trask. 



Plate IV, Fiu. 7. 



Fusus rugosus Trxsk, Proc. Cal. Acad. Sci., Vol. I, 1855, p 41. Cooper, 7th Ann. Rept. Cal. St. 

 Min., 1888,. p. 241. 



Shell of medium size, elongate, fusiform, thin; whorls eight, convex, crossed by eight to 

 eleven rounded ridges, which rise to greatest prominence on upper side of whorl; body-whorl ventri- 

 cose and sometimes lacking transverse ridges on forward part; surface ornamented with several 

 prominent raised lines, with fine lines sometimes intercalated; suture deej)ly appressed, wavy; 

 aperture elliptical; outer lip thin, with interior spiral ridges extending nearly to rim; inner lip smooth; 

 columella long, slightly twisted, spirally ridged; canal long, narrow, slightly curved. 



Dimensions. — Long. 50 mm.; lat. 19 mm.; body-whorl 35 mm.; aperture, including canal, 

 28 mm.; canal 13 mm.; defl. 44 degrees. 



The specimen described and figured is a small one. Some of the specimens 

 are over 65 ram. in length. 



Distinguishable from F. robustus by larger size, thinner shell, longer canal, 

 more ventricose body-whorl, and greater development of transverse ridges on upper 

 portion of whorl. Perhaps F. rugosus is the precursor of F. robustus. If so, then 



