Achatinella and other Pahnonata. 347 



tooth, the side cusps being subobsolete. The Uiteral teeth are like the 

 centrals, but uusj-m metrical. The margiual teeth are about as wide as 

 high, with one stout, pointed inner cusp, and two short, side cusps. 



HeSix l»rOTi!iOi*i», Pfr. (Thelidomus^. 



New Providence, Bahamas (also Cuba). Gov. Rawson.* 



Jaw very sliglitly arcuate, wide, low, of about equal height thi'oughout ; 

 ends blunt; anterior surface with 10-15 ribs, separated by irregular inter- 

 vals, not always reaching the cutting edge, wljich has a broad, blunt 

 median projection. 



Lingual membrane with numerous rows of about 40-1-40 teeth, as 

 usual in the Ilelicidcc, the marginals liaving one large and one side, small, 

 blunt cusp, projecting but sliglitly beyond the base of the tooth. 



CS^Santlilia SOIMiaHa, Pfr. (Oleacina). 

 New Providence (also Cuba). 

 Lingual membrane as usual in the genus. 



SailiimilMiS seiMilcralifi, Poey {Leptomerus). 

 New Providence (also Cuba). 



Jaw stout, wide, low, arcuate, of about equal height throughout ; ends 

 bluntly rounded; with fifteen stout, broad, crowded ribs, their ends cre- 

 nellating either margin. Some of these ribs are of equal thickness 

 throughout their whole breadth, and are separated by decided narrow in- 

 terstices. The jaw cannot, thei-efore, be said to be in numerous plate-like 

 sections separated by narrow ribs, as is usual in Bulimnlus. This jaw is 

 of interest as showing the passage from the jaw of Cylinclrella, BnJimulus, 

 etc., to that of Helix, having some of the characters of each. 



Lingual membrane as usual in the Helicidce. Side cusps of centrals and 

 laterals obsolete, median cusp long, with a long point, passing beyond the 

 base of the tooth. The upper margin of the centrals is incurved. Margi- 

 nal teeth a modification of the latei-als, with one long, narrow, blunt, 

 inner denticle, and one or two short side denticles of similar shape. 



*TI)e animals of this, the four following:, and other Bahamas species were sometime 

 since received from Gov. Rawson by Bland, to whom the shells collected by the late Dr. 

 Bryant were referred by the Boston Society of J^atural History. The jaw .^ and lingual 

 membranes of the species were placed by Bland at the disposal of the society, and at 

 his suggestion were mounted for microscopic examination. We are indebted to the 

 Society for the use of the slides. 

 November, 1873. 24 Akn. Ltc. Nat. Hist., Vol. x. 



