with Descrijytioiis of Neio Species. 3 



Cylindrella and Testacella^ referred to by Sclimidt, is more 

 apparent than real, being confined to the oblique arrangement 

 of the lateral teeth. 



An unlooked-for discovery was announced by Crosse and 

 Fischer in a very interesting paper in the January number 

 (1868) of the Joicrnal de Conchyliologie . After remarking that 

 autliors have repeated the assertion of Schmidt that Cylin^ 

 drella has no jaw, and explaining that an opportunity had 

 recently occurred of examining the animal of C. Gliiesbreghti 

 Pfr., Crosse and Fischer give the result in a passage of which 

 tlie following is a translation : 



"We have proved the presence in this species of a jaw, arcuate, 

 horse-shoe shaped, very finely striated longitudinally, with an ob- 

 solete, slightly indicated median projection at the inferior margin, 

 and a rounded plate or support projecting beyond the edge of the 

 superior margin. 



" The lingual armature is, moreover, very remarkable. The lingual 

 denticulations are disposed in rectilhiear transverse series, nume- 

 rous and all of the same type, with apices scarcely extending be- 

 yond their base, the single median or rachidian tooth is a little 

 smaller than the others, and tricuspid. The dental formula is (32- 

 1-32) X 110. 



" Considering the nature of its teeth the animal must be her- 

 bivorous and not zoophagous. The classifications which have 

 placed the molluscs of this group with the cmmivoroiis Pulmonates 

 are then erroneous and altogether defective. The reserve which 

 we have shown in this respect in our Journal was clearly justifiable. 



" In the Cylindrellae of the Antilles, on the other hand, the rows of 

 teeth are so oblique that they appear to have a quincuncial arrange- 

 ment ; each row composed of a small number of teeth of peculiar 

 palmated form ; the rachidian tooth is of a very difierent type, ex- 

 tremely narrow and enlarged at one of its extremities. We have 

 not been able to find the jaw in C. sanguinea Pfr. of Jamaica, which 

 we have examined, and of which the dental formula is (12-1-12) 

 X 115. 



" Considering these important anatomical difierences, we think it 

 consistent to separate from the genus Cylindrella., the group, very 

 natural, moreover, with reference to zoological geography, of large 

 species from Central America (Mexico and Guatemala), of which C. 



