MUSEUM OF COMPARATIVE ZOOLOGY. 403 



denticulated at the end and tufted, the next four are denticulated but without 

 tufts, the rest, about forty-five in number, are more simple, and become still 

 more simple and smaller toward the margin of the radula. The tooth formula 

 would be written, R -(- (15) -+- (5 -+- 4 -+■ 45), without trying to exemplify the 

 minor uncinal armature. 



Morch (Malak. Blatt., XXII. p. 184, 1875) has described a supposed species 

 of Murchisonia, — M. (Murchisonella) spectrum, — from St. Thomas, collected 

 by Riise, measuring 2.0 by 0.75 mm., and having ten whorls. 



From the small size of this shell I suspect it to belong to the Turritellidce, — 

 many of which have notches or waves, recalling those of Seguenzia, in the 

 margin of the aperture, — or at least to some group unconnected with the typi- 

 cal Murchisonia. 



Family FISSURELLID^E. 

 Genus PUNCTURELLA Lowe. 



Subgenus PUNCTURELLA s. s. 



Puncturella circularis Dall 



Plate XXVI. Figs. 7, 7 b. 

 Puncturella circularis Dall, Bull. M. C. Z., IX. p. 75, 1881- 



Habitat. Station 44, in 539 ims. 



No more specimens have turned up, and a comparison of this and the follow- 

 ing species with others contained in the Jeffreys collection confirms to that 

 extent their distinctness. 



Puncturella trifolium Ball. 



Plate XXVI. Figs. 8,8 b. 

 Puncturella trifolium Dall, Bull. M. C. Z., IX. p. 76, 1881. 

 Habitat. Yucatan Strait, in 640 fms. 



Puncturella Watsoni n. s. 



Shell small, greenish white, exactly resembling in sculpture Cranopsis 

 granulata Seguenza (Chall. Gastr., p. 46, pi. iv. fig. 5), but differing from that 

 species in having the slit of Puncturella instead of Cranopsis, and in having a 

 rather higher and narrower and more conical form. The anterior and posterior 

 slopes are not arched to the same extent as in the C. granulata, and the shell 

 is proportionately shorter. The nucleus is small and prominent, and the 

 shell as a whole includes two whorls. Max. alt., 3.0; max. diam.. 2.5: mas. 

 Ion., 3.8 mm. 



