404 PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



Soft parts in general as in the last species, except tliat the bead and 

 muzzle are mucli elongated, the sinus behind the bead deep ; gill longer 

 and larger tlian in C. liathbuni, projecting out on the right side of the 

 head ; tentacles longer and foot shorter proportionally than in C. Rath- 

 huni; the mantle margin is much i)uckered, but this is probably due to 

 the alcohol ; the margination, which forms a semilunar area at the end 

 of the muzzle in the preceding species, in 0. Beanii is interrnpted be- 

 fore the papillose area which here distinctly forms the end of the muz- 

 zle, the effect of which is to produce two lappets, one on each side, 

 extending from the end of the muzzle to the anterior edge of the foot. 

 There appears to be no jaw. 



Dentition. — In this species the bands of uncini are proportionally 

 longer and wider and the rhachidian tooth smaller than in the preceding. 

 The rhachidian tooth is small, with a tri<leutate cusp and bifurcate base; 

 it is about half as long as and hardly wider than the first three laterals; 

 the latter are elongate, slender, with denticulate cusps, the outer is 

 rather the shorter in the matnre part of the radula ; the major lateral 

 is longer, with a more slender shaft than in C. Rathbuni, and a proj)or- 

 tionally larger, very conct^^e cttsp with seven or eight denticulations; 

 the banded uncini are singly broader than in C. Rathbuni, and collect- 

 ively about one-half longer. 



Habitat.— Station 871, JJ. S. Fish Commission, lat. 40^ 02' 54" :N"., 

 Ion. 70° 23' 40" W., in 115 fathoms muddy sand ; station 894, U. S. Fish 

 Commission, lat. 3&o 53' Is^., Ion. 70° 58' 30" W., 305 fathoms mud and 

 gravel, both in 1880; station 947, 312 fathoms sandy mud, bottom tem- 

 perature 44° F. ; station 949, 79i miles south of Martha's Vineyard, in 

 100 fathoms yellow mud, bottom temperature 52o.O, surface GG^'.O F.; 

 station 997, 335 fathoms, yellow mud, bottom temperature 40° F. ; these 

 lavSt in 1881 (Verrill); and*from the same localities as C. Railibnni in the 

 West Indies (Agassiz), with the additional locality of station 204, 416 

 fathoms gray ooze, off Grenada, bottom temi)erature 42o.5 F.* It is 

 named in honor of Dr. T. II. Bean, of the United States Fish Com- 

 mission. 



Family ADDISOXIID^. Dall. 



Shell asymmetrical, porcellanons, somewhat like Capidacmcea Sars. 



Soft parts much as in the last fiimily, but strongly asymmetrical, 

 with an enormottsly developed lateral series of separately inserted gill- 

 laminae, like those of Patellidce, and without filamentary appendages of 

 any kind. Kadula with a large simple rhachidian tooth with, on each 

 side, tw^o large simple transverse laterals, followed by two minute ones, 

 and a large outer lateral with a strong tridentate cusp, outside of which 



*This is, perhaps, the shell referred to under the name of "Acmcea rtibella^ Fabr." 

 Verrill, Proc. U. S. Nat. Mus., Ill, p. 391, dredged (dead) at station 894, United States 

 Fish Commission, 1880, off the S. E. coast of New England, in 39^ 53' N., 70^ 58' 30" 

 W., in 365 fathoms. 



