274 bulletin: museum of comparative zoology.^ 



lines of growth, crossed by numerous very sharp, narrow, prominent, subequal 

 spiral ridges with about equal or narrower interspaces ; the periphery is formed by 

 a sort of rib, on which stand two to four similar keels, but smaller than the others 

 and more crowded; in front of the rib there is a faint constriction of the whorl ; 

 the keels are less prominent on tiie canal, which is moderately long and recurved ; on 

 the penultimate whorl there are about fourteen keels between the sutures ; aperture 

 elongate, reflecting the sculpture, but without lirae ; outer lip very f.exuous, with 

 a broad, rather shallow anal sulcus behind, and arched forward in front of the 

 peripheral rib ; body white, not callous ; pillar thin, attenuated, and obliquely 

 truncate in front, concave, twisted, exhibiting a pervious axis ; canal shallow, not 

 producing a fascicle ; operculum like that of Mohniafrielei. Height of shell, 60 ; 

 of last whorl, 48 ; of aperture, 38 ; max. diam. 26 mm. 



U. S. S. "Albatross," station 3415, off Acapulco, Mexico, in 1879 fathoms, 

 globigerina ooze, bottom temperature 36° F. U. S. N. Mus. 123,099. Also at 

 station 3381, east of Malpelo Island, Gulf of Panama, in 1772 fathoms, mud, 

 bottom temperature 35°. 8 F. U. S. N. Mus. 123,098. 



The initiatory part of the operculum is spiral, as in Mohnia, thus differing from 

 the typical deep-water Turritidae, which it in general resembles. They have the 

 nucleus of the operculum apical and not spiral. It differs from the operculum of 

 Irenosyrinx in being enlarged at the inner posterior margin as in Lunatia, so that 

 the spiral apex remains apical, while in Irenosyrinx the operculum after a brief 

 period of spiral growth is entirely surrounded by concentric additions, so that the 

 spiral portion is within a subsequent concentric margin, like the nucleus of the 

 operculum in Buccinum. 



CALHOTECTUM Ball. 

 Calliotectum Dall, Proc. U. S. Nat. ilus., 1889, 12, p. 304. 



Calliotectum vernicosum Dall. 



Calliotectum vernicosum Dall op. cit., p. 304, pi. 5, fig. 8, 1889. 



U. S. S. "Albatross," station 2793, off the coast of Ecuador, in 741 fathoms, mud ; 

 station 2807, near the Galapagos Islands, in 812 fathoms, mud, bottom tempera- 

 ture in both cases 38°. 4 F. Also at station 3407, off the Galapagos Islands iu 

 885 fathoms, bottom temperature 37°. 2; and at station 4654 twenty-four miles 

 W. 68° N. from Aguja Point on the Peruvian coast, in 1036 fathoms, mud, bottom 

 temperature 37°.3. Both tlie latter stations afforded fragments only. 



A full account of the animal was given in the publication of 1889. 



