304 CALIFORNIA ACADKMY nl" SCIENCES. 



Distiiitruitfliiilili.' from other iuciiiIkts nf llic i;('iiii'< loiiml in lliis t'liiinaiimi hy 

 its elevated spire, deeply impressed siitnic, and .-iiiull (Utlcclidn. 'i'lie spcciinoii 

 described was identified liy I)r. 1)mII. 



Rare in lower San Tcdro series at Deadman Island and upper San Pedro 

 scries at San Pedro. Found also in the Pleistoeeiie at PacKic Peach, San Diego. 

 The speeiuien lij^ured is somewhat decorticated, came from I lie upper San Pedro 

 series at San Pedro, and is now in the collection of Delos Arnold. 



Living- Ala>ka to San Diego (Cooper). 



Pleistocene. — Santa Barbara to San Diego (Cooper): San Pedro; San 

 Diego (Arnold). 



Family LXXIV. FOSSARID.E. 

 Genus Fossarus Philippl. 

 Shell perforated, sculptured; inner lip thin; aperture semilunate. 

 Fossarus cosiaUts Brocchi is a characteristic species. 



Subgenus Isapis J/, cf- A. Addms. 



Shell umbilicated; spire elevated; cancellated, or with revolving ribs; columella with a small 

 median tooth. 



Isapis anomala C. B. Adams is a characteristic si^ecies. 



337. Fossarus (Isapis) fenestrata Carpenter. 



Isapis /enestrala CvR., Brit. A.ssn. Rept., 1S63, p. 656; Ann. & Mag. Nat. Hist., 3rd Ser. , Vol. XV, 

 1865, p. 28. Keep, West Coast Shells, p. 65, 1892. Williamson, Proc. U- S. Nat. 

 Mus., Vol. XV, 1892, p. 206. 



Shell small, turreted; spire elevated, subacute; whorls four, .slightly convex, ornamented 

 with prominent, squarish, raised, spiral ridges, with numerous fine, oblique lirula- in the interspaces; 

 three spiral ridges on penultimate whorl, twelve to thirteen on body-whorl; suture deeply impressed, 

 distinct; aperture ovate; outer lip thin, slightly effuse; inner lip flattened, effuse; umbilical 

 chink small. 



Dimensions. — Long. 8 mm.; hit. 7 mm.; body-whorl 7 mm.; aperture, 5 mm.; defl. 

 65 degrees. 



Found in the lower San Pedro series of Deadman Island and San Pedro, and 

 in the upper San Pedro series at Crawfish George's, San Pedro, and Deadman Island. 

 Living. — Vancouver to San Diego (Carpenter). 

 Pleistocene. — San Pedro (Arnold). 



Family LXXV. RISSOIDiE. 



Genus Rissoa Frendnville. 



.Shell minute, white or horny; conical pointed, many-whorled; smooth, ribbed or cancel- 

 lated; aperture rounded; peristome entire, continuous; outer lip slightly expanded, thickened. 



Hissoa costulata Risso is a characteristic species. 



