MUSEUM OF COMPARATIVE ZOOLOGY. 339 



which is entirely diirereut. The |ireseiit species lias the mouth of a Turhonilla. 

 It is now for the first time reported from the United States. 



This jrroup is related to the ordinary Turbonilltc, much as Cingula aculeus 

 Gould is to the species of Alvania, or as yEsopiis is to Anadiis. 



Amaui'a (Amowa by err. tyj).) aiKjulifcrens De Folin, probably, im(\. Jaminea 

 Duponti De Folin, from Mauritius, certainly, belong to this section. 



? Genus SYRNOLA A. Adams. 

 Subgenus OSCILLA A. Adams. 



This group was according to Tryon proposed for forms of the Sijrnola type, 

 with strong spiral sculpture and a single strong spiral parietal plait. I have 

 not seen the type, or even a good figure of it, if the above statement be cor- 

 rect, for Adams's figure in the Thesaurus (pi. clxxi. fig. 26) shows distinctly 

 three plaits, which are even perceptible in Tryon's copy of it (pi. Ixxiv. fig. 

 28). Then Morch in the Malak. Blatter (Vol. XXII. p. 158, 1875) proposes 

 a new subgenus Triptychiis, which is said to differ from Oscilla by "columella 

 triplicata nee uniplicata." I presume that the diagnosis in the Thesaurus 

 merely meant that there was one strong plait beside the two fainter ones, and 

 the name Oscilla was based rather on the sculpture than the plaits. I have no 

 doubt that Oscilla and Triptychus are synonymous, and the 0. annulata and 

 Morch's T. nivca (my Fyramidella ? vincta of a later date) are even very simi- 

 lar species. 



Oscilla nivea is found in the Florida Keys, in St. Domingo, St. Thomas, St. 

 Martin, and Vieque. If this species be a proper representative of the group, 

 I should feel disposed to separate it generically from Syrnola, for it certainly 

 has quite peculiar characters. The strong parietal spiral thread is really the 

 result of the basal sculpture, which enters the aperture and is overlaid with 

 callus. The strong plait on the pillar is also coincident with a basal cord, 

 which coils around the pillar and is much enlarged by the addition of callus. 

 The two fainter anterior plaits are often obsolete, or nearly so. None of thera 

 have the horizontality and sharpness, like that of a screw-thread, so character- 

 istic of Fyramidella proper, and yet they do not turn in with a twist like the 

 pillar lip of Syrnola. The outer lip is Urate in the adult. 



? Genus PERISTICHIA Dall. 



Shell elongated, acute, many-whorled, dextral, with a small sinistral nucleus, 

 spirally or reticulately sculptured; aperture ovate, lips thickened; columella 

 straight, simple, without ^ilaits; a basal cord entering the aperture on the body 

 between the pillar and the outer lip; aperture anteriorly a little effuse, but not 

 channelled in front of the pillar; outer lip varicoid in the adult, internally wdth 

 a few very strong lirce; soft parts ? 



Type, Peristichia toreta Dall, Florida Keys. 



