INSTITUTE OF SCIENCE, PHILADELPHIA. II9 



N. E. from Tampa ; also on the Chipola River, one mile below Bailey's Ferry, 

 West Florida. 



This species, like the others, has a spiny and a smooth form, though the 

 latter usually acquires a few spines when fully adult. The young smooth 

 form has been figured, which will be comparable with the figure of il^ sub- 

 coronata var. aspinosa (PI. 9, fig. 6). The chief characters of this species are 

 as follows : 



Shell of eight or nine whorls, rather elongated, with rather sharp, elevated, 

 incremental lines, crossed by sharp-edged spiral threads of varying strength, 

 so as to give a rather rasp-like surface-sculpture. The species exhibits two 

 varieties, of which the extremes differ greatly from one another, though con- 

 nected by minute gradations when a sufficient series is studied. 



M. sculptwata var. sculpturata Dall. In this form the whorls are 

 somewhat imbricated at the suture and decline with a rather steep 

 slope to the series of spines at the shoulder, which are triangular and 

 compressed ; they number about eight on the last whorl ; on the base 

 a similar series of five or six shorter spines often encircles the canal 

 about one-third of the way from the siphonal fasciole to the series at 

 the shoulder ; siphonal fasciole strong, arcuate, sometimes imbricated, 

 but not spiny ; aperture elongate, smooth inside ; pillar with a moder- 

 ate callus, reflected anteriorly as far as the fasciole, but without any 

 umbilical chink ; canal well defined^ rather short and wide ; whorls coiled 

 rather closely just in front of the posterior series of .spines, so that the even 

 slope of the spire is a prominent feature. The spirals are alternated, from one 

 to three sharp secondary threads between every two primaries ; the earlier 

 whorls have proportionately more spines than the later ones, as usual in this 

 group. A young specimen measures, inclusive of 13 mm. of spines, 50 x 80 

 mm., the aperture being 60 mm. long. The adults, judging from fragments, 

 will measure 160 mm. in length occasionally. 



This form was found at Chipola and also possible fragments in the silex- 

 beds, but quite rarely. It is more numerous in the Ceritlmtm rock with C. 

 hillsboroeiisis Heilprin, 



Melongena sculpturata var. turricula Dall. 



Plate 8, figure 3. 



In this variety the surface-sculpture is retained, but instead of a series of 

 spines at the shoulder we have an undulate or even a simple keel, while the 

 anterior series of spines is absent, the slope of the shoulder more nearly ap- 

 proaches the horizontal, the axis of the shell being regarded as vertical, while 

 the suture is simple and destitute of imbrications. The result of these changes 

 is that the shell has a more turrited spire and a very different appearance from 

 that of the type, with which it is nevertheless united by imperceptible grada- 

 tions. The specimen figured had lost its tip, which has been supplied from 



