MINUTE SHELLS. 65 



Another similar shell from San Diego is named 

 Barleeia subtenuis, Cpr., sub-ten'-u-is. It is some- 

 what larger and less slender, and is sometimes found 

 on grass. 



Alvania cequisciilpta, Cpr., Al-van'-i-a e-qui-sculp'- 

 ta, has a shell, minute, slender, and coarsely cancel- 

 lated. The spire is five-whorled, and the aperture 

 is circular and entire. Its color is white, and its 

 length is only one-eighth of an inch. 



Rissoa aciitelirata, Cpr., Ris r -so-a a-ku-te-li-ra'-ta, 

 resembles the last species, but is even smaller. It is 

 brownish and very beautifully marked by numerous 

 fine ribs and lines, which are clearly brought out by 

 a lens. 



Rissoina interfossa, Cpr., Ris-so-i'-na in-ter-fos'-sa, 

 has a slender, sharply conical shell. The seven or 

 eight whorls are cut into squares by a few bold, spiral 

 ridges, which are crossed by numerous ribs. The 

 aperture is quite small, oval, and notched at the base. 

 The shell is white, and its length is over one-fourth 

 of an inch. 



Clathiirella inter clathrata, Cpr., is smaller and 

 more slender than the last. The brown surface 

 is cancellated, and the aperture is distinctly notched. 



Isapis obtusa, Cpr., I-sa'-pis ob-tu'-sa, has a round- 

 ish little shell, less than a quarter of an inch in 

 length. The aperture is oval, and the outer lip is 

 marked by scallops, while the general surface is 

 diversified by shallow spiral grooves. The spire is 

 small and few-whorled ; the color is light brown. 



Isapis fenestrata, Cpr. , fe-nes-tra'-ta, much resem- 

 bles the last, but is marked by sharp spiral ridges. 



Three little shells next engage our attention, and 

 call for a brief explanation of their common name. 



(5) 



