OF CONCHOLOGY. 213 



thrown on the subject by the lingual of Achatina virginea (see 

 above) it may bo that wiiat we have called laterals are really 

 uncini. 



Our figure gives one central and one lateral tooth, and one 

 detached extreme lateral from the other side of the lingual- 

 membrane. 



Orthalicus undatus, (Plate 9, fig. 10, 12.) 



A specimen received from Pear Island furnished the lingual 

 membrane here described. 



Teeth arranged as described in Orthalicus zeb7'a, and about as 

 numerous, one line counting 53 — 1 — 53 teeth. 



Teeth in all essential points resembling those of 0. zebra, (see 

 above.) The centrals are broader than in that species and the 

 uncini have a more expanded cusp. 



Jaw strongly arched, ends attenuated, bluntly pointed, com- 

 posed of twelve separate plates. 



Figure 10 gives one central and one lateral tooth ; fig. 12 

 gives one extreme lateral. 



SucciNEA EFFUSA, Shuttleworth, (Plate 9, fig. 15.) 



A specimen from Florida preserved in the Museum of Com- 

 parative Zoology at Cambridge, furnished the jaw and lingual 

 membrane here described. 



Jaw strongly arched ; ends blunt, attenuated ; cutting edge 

 deeply concave and furnished with a prominent pointed beak ; 

 anterior surface with vertical and horizontal strife, but no grooves 

 or rib-like processes ; accessory plate large, subquadrate. 



The lingual membrane resembles that of jS. avara, figured in 

 Land and Fr. W. Sh., I., p. 263. There appear to be about 

 15 — 1 — 15 teeth in each row. Our figure gives one central and 

 one lateral tooth. 



Megalomastoma bituberculatum, Sowb. 



The specimen from which were extracted the jaw and lingual 

 membrane here described, was received from Seilor D. Rafael 

 Arango, of Havana. 



Jaw consisting of two subtriangular symmetrical plates, thick- 

 ened towards the inner and lower edges, thinning outward and 

 upward ; with a decided thickened rim running parallel to the 

 inner edge, and extending above and below the body of the 

 plates ; surface closely covered with oblique rows of small quad- 

 rate scales. Generally resembling the jaw of 31. cylindraceum, 

 figured in American Journal of Conchology, I., pi. 5, f. 2. 



Lingual membrane long and narrow. Teeth 3 — 1 — 3, arranged 

 in numerous chevron-shaped transverse rows. Centrals upright, 



