FAMILY PATELLID;E — PATELLA. 161 



(EXTRA-LIMITAL.) 



D. attenuatum. (Say, Journ. Acad. Vol. 4, p. 154, pi. 8, fig. 3.) Shell arcuated: surface with from 

 12 - 16 rounded ribs, the intervening grooves simple; lines of growth numerous, distinct; aper- 

 ture orbicular. Length- 1-7. Fossil. Maryland. 



Note. The size and fewer longitudinal ribs, with its fossil condition, induce me to consider it as 

 distinct from the preceding. 



SECTION 8. CYCLOBRANCHIA. 



Animal furnished with a foot for crawling. Gills in the form of lamella, in a series more 

 or less complete, in the furrow between the mantle and body ; or a small gill on the 

 right side of the head. Sexes united. Shell not spiral, covering the soft parts, and 

 of one or many pieces. 



Note. I have retained the name of this section, although it is not significant in its present 

 extended meaning. 



FAMILY PATELLIDJS. 



Animal furnished with tentacles, and eyes at their external base. Gills forming a series of 

 lamella around the body or on the side of the neck. Shell univalve, cup-shaped. 



GENUS PATELLA. Linnaus. 



Animal with a very distinct head, terminated in a thick and short trunk. Vent on the neck, 

 back of the head. Mouth fleshy with a long prickly tongue, which folds itself in the vis- 

 ceral cavity. Duct of the ovary near the right tentacle. Gills arranged round the body 

 in a series of lamellae. Shell conical, cup-shaped, solid : apex nearly central. 



Patella Candida. 



Patella Candida. Codthooy, Bost. Jour. Nat. Hist. Vol. 2, p. 86, pi. 3, fig. 17. 

 P. id. Gould, Invertebrata of Mass. p. 152. 



Description. Shell small, conical, with numerous minute revolving ribs, traversed by 

 equally fine concentric lines, giving the surface under the lens the appearance of net-work. 

 Summit nearly central : margin slightly scolloped by the termination of the ribs. Color, 

 white. 



Length, • 35. Height, • 1 . 



Stomachs of fishes. Coast of Massachusetts. First noticed by Mr. Couthouy ; but three 

 specimens found. 



a una — Part 6. 21 



