Cyclostrema, Adeorbis, Vitrinella, and related genera. 129 



Mr. Jeffreys in 1875 changed his mind in regard to supranitidiis^ 

 Wood, as the " Lightning and Porcupine Expedition," obtained speci- 

 mens which he mentioned as " agreeing with the Crag specimens 

 in every respect (especially in being tricarinated) except in being 

 spirally and rather strongly striated," and added A. tricarinatus 

 Wood as another variety. He further mentioned that " the opercu- 

 lum is not known, and it is therefore questionable whether the pre- 

 sent species belongs to Adeorhis or Homalaxis.'''' He however 

 referred it to Adeorbis, but did not mention his genus Circidus. 



Lissospira gen. nov. 



Gyelosirema auth. in part. 



This genus is proposed for a group of deep-water species which 

 have been erroneously referred to Cyclostrema. They are small, 

 thin, of rather delicate texture, opaque white, slightly lustrous, of 

 few convex whorls forming an elevated spire, with relatively large, 

 prominent nuclear whorl and large body-whorl. Suture deep, 

 Umbilicus small, deep, not showing any whorls. Aperture somewhat 

 oblique, circular with a slight sutural angle, not modified by the 

 bodj^-whorl to which the simple, continuous peritreme is but slightly 

 attached, often having an indistinct thread just within the inner lip, 

 fading out above and below, so that it extends but about half way 

 round the aperture ; it is much nearer the edge along the columellar 

 margin than at the ends and is evidently to prevent the thin oper- 

 culum being drawn in too far. The operculum (fig. 4) is circular, 

 thin, of a delicate horn-color, with central nucleus, of about seven 

 whorls, defined by a distinct spiral thread ; often showing delicate, 

 microscopic transverse growth lines. The radula consists of numer- 

 ous rows of delicate teeth ; each row having one broad central, or 

 median tooth, with a broad, blunt, delicately serrate, curved tip and 

 on either side four more slender lateral teeth also with blunt, curved, 

 delicately serrate tips, beyond which is a series of numerous, between 

 30 and 50, long, very slender, somewhat sickle-shaped hooks some- 

 times with delicately serrate tips. (G. O. Sars, Moll. Reg. Arct. 

 Norv., tab. iii. f, 6 b. and L. diaphana.) 



' The locality (New England, Verrill) given by Mr. Jeffreys, I have been unable to 

 verify, as I find no such species on record or mention of it in any of Professor Verrill's 

 papers. 



Trans. Conn. Acad., Vol. X. July, 1897. 



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