1869.] 127 [Perkins. 



Common on algse near lew water. Full grown shells are much less 

 common than young ones. Animal small, purplish ; rostrum rounded, 

 about half as long as the tentacles, deeply bilobed; tentacles slender, 

 white, banded with dark purple, tapering but little ; eyes on short 

 pedicels connate with the outer bases of the tentacles ; foot light be- 

 low, spotted with purple, dark above, long and narrow, obtusely 

 pointed behind, expanded in front; operculum thin, corneous, ovate, 

 with a circular thickened upper part, marked with spiral lines of 

 growth, and a sub-triangular and thinner lower part. 



MEASUREMENTS. 



Length of shell 5 mill. Breadth 2 mill. 



" tentacles 1.6 " 



" foot 3 



" opei-culum l.G " 



Bittium Greenii Stimps., Check List. Cerithium Greenii C. B. 

 Adams, Bost. Journ. Nat. Hist., Vol. n, p. 287, pi. iv,fig. 12; Gould, 

 Invert. Mass., p. 279, fig. 184; De Kay, Moll. N. Y., p. 130. 



Very rare. 



Tectura Audouin, 1830. 



Tectura testudinalis Stimps., Check List. Patella testudinalis 

 Miill. Patella amcena Say, Am. Conch., p. 73, 1822. Patelloida 

 amcena Couthouy, Bost. Journ. Nat. Hist., Vol. n, p. 171. Patelloida 

 testudinalis De Kay, Moll. N. Y., p. 162, pi. xix, fig. 196. Loilia 

 testudinalis Gould, Invert. Mass., p. 153, fig. 12. 



Very rare. I am indebted for the only specimen that I have seen 

 from here to Mr. Geo. Williams. It is much more conical, and the 

 apex farther forward than most of those from farther north. Animal 

 oval, white; mantle not extending beyond the edge of the shell, 

 fringed with rather long, uneven papillae, light blue, with a darker 

 line around the edge ; rostrum short, rounded ; tentacles moderately 

 long, tapering, blunt at the ends, setose along the sides, bluish hya- 

 line white, with an opaque white line through the centre, barred with 

 broad lines of the same, when contracted curved about the rostrum; 

 eyes on the outer bases; branchial plume white, longer than the 

 tentacles, tapering gradually from the base, lamellae longest behind 

 the midrib, arcuate; foot ovate, pointed behind, when contracted 

 folded longitudinally upon itself; lingual ribbon long and narrow. 



