130 AMERICAN JOURNAL 



The umbilicus is either smoothly coyered with callus, or a 

 small pit may exist. 



The whorls of a variety (fluctuatum, Dall) are marked with 

 oblique, prominent, rounded, short riblets. The shell may be 

 produced, rugged and subcylindrical, or rather depressed and 

 smooth. 



PachypOxMA gibberosum, Chemn. 



On the sea beach outside of Point Pinos, Monterey. Alive 

 on rocks, feeding on Algce and Laminaria. Muzzle short, 

 squarish ; pointed bases covered by, but not connected with two 

 small semilunar lobes, the rudiments of the "veil." Eye pedi- 

 cles above and outside of tentacles, both being cylindrical, 

 thick, and non-retractile. Cloak divided behind with a single 

 posterior tentaculate filament on each side. Foot rounded, 

 regularly granulated on the sides. Color red and purple mixed, 

 lighter on top of head and edges of cloak. Mantle large, yel- 

 lowish, as well as the upper part of the cloak. Edges of the 

 mantle very brilliant yellow. 



LEPTOTHYRA, Opr. 



Leptothyra, Cpr., MSS. 



Leptonyx, Cpr. and A. Ad., Proc. Cal. Acad, iii, p. 175, 



not of Swainson or Gray. 

 Ilomalopoma, Cpr., Suppl. Rep. Brit. As. for 1863, p. 537, 



1864. 



Type Leptonyx (= Leptothyra) sanguinea, Cpr., p. 176, loc. 

 cit. as of Lin. 



= Turbo sanguineus, Lin., Syst. Nat. xii, p. 1235, teste Cpr. 



Hani. 

 = Turbo Bellicei, Mich., teste Hani. 



Hab., C. St. Lucas to Neeah Bay, Japan, Medit. 



I have several small specimens of this species, collected by 

 Capt. Christopher C. Dall at Cape St. Lucas. The variety 

 purpurea, described by Dr. Carpenter, has, by the examination 

 of many thousands of specimens, proved to graduate into the 

 other forms so insensibly as to be hardly worthy of a separate 

 varietal name. This, however, was not known at the time it was 

 originally described. The species is of all shades of crimson 

 and purple, some specimens being banded with white or having 

 the red color of the ribs interrupted by oblique streaks of 

 white, some specimens, excepting the dark apex, being pure 

 white. 



