PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 337 



middle, anteriorly rounded and sharp to its union with the inner margin. 

 Aperture very narrow posteriorly, suddenly enlarging to an ovate form 

 anteriorly, by the decided excurvature of the inner margin. Animal 

 unknown. 



Length of largest example, 10'"™; breadth, 5.25™'". 



Stations 997 and 999, in 335 and 266 fathoms. 



PhiUne tincta Verrill. 



Trans. Couu. Acad., v, p. 544, July, 1882. 



Shell very thin, rather large, irregularly oblong, broad, widest in the 

 middle, not polished, tinged with smoky brown; surface without dis- 

 tinct spiral lines, covered with very e\'ideut, close, raised, wavy lines of 

 growth. Apex rounded, neither spiral nor depressed. Outer lip rising 

 a little above the body- whorl, and separated from it by a simple wide 

 sinus, flaring, convex, and slightly angulated in the middle, a little 

 narrowed and well rounded anteriorly; a spiral fold where the inner lip 

 passes into the shell, in front of the prominent body-whorl. 



Length, 10.75™'"; breadth, 8™™; breadth of aperture, 7™™. 



Station 921, in 65 fathoms; two living specimens. 



CHomsTiDiE Verrill. 



The peculiar structure of the animal of the following species, and of 

 its radula, will not allow it to be placed in any established family. 

 Therefore, I propose to make it the type of a new family, Choristidev. 



This family may be characterized by the heliciform shell, with the 

 periostraca continuous betw^een the whorls; lip continuous; columella 

 without a fold; operculum horny, paucispiral. Animal with frontal 

 tentacles united by a fold, and with simple posterior tentacles. Jaws 

 well developed ; pharynx large, retractile. 



Eadula with three rows of rachidian teeth, the central ones small; 

 with broad, bilobed, inner lateral teeth; and two rows of small, hook- 

 shaped outer lateral ones. Gill composed of numerous lamelhp, attached 

 to the inner surface of the mantle on the left side and over the neck. 



The position of this family is doubtful. Its head, tentacles, pharynx, 

 &c., resemble those of many TccUbranchs. Its dentition is, apjiareutly, 

 unique. 



Choristes elegans Carp., var. tenera V. 



Verrill, Trans. Conn. Acad., v, p. 541, pi. 58, figs. 27, 27rt, 

 Choristes elegans Carpenter, Canadian Nat., p. 392, pi. 7, fig. 13, 1872. 

 Shell thin, fragile, short, heliciform, with a low spire, and a very large, 

 ventricose body-whorl. Whorls, in our largest examples, four to five, 

 very convex, evenly rounded; apical whorl small, spiral, oblique; suture 

 Impressed; surface smooth (the epidermis is destroyed and the surface 

 of the shell is eroded in all the living examples). The whorls are in con- 

 tact and united, but the epidermis continues around the whorls between 

 Proc. Nat. Mus. 82 22 Sept. 5,18 82. 



