

ton Lingual Dentition of MoUvsca. 



Tichiiiipu* bidentatus, Say. 



T - :imen which furnished the lingual membrane figured 



I at Newport, R. I., by Mr. Sam. Powel. 



I'm;. 7. 



Ungual dentition of Melampna bidentatus, Bay. 



Lingual membrane broad. r l\-ctli 33.1.33. Centrals small, 

 upri^'nt. with rounding base and bulging sides, reminding one 

 somewhat of the ace of clubs, its apex elongated, terminating in 

 jtinct, acute denticle; this central is attached to a very large 

 triangular plate, greatly expanded above. Laterals uniform, 

 larger than the centrals, of the same shape, but less symmetrical, 

 and with a much more extended and narrower basal projection ; 

 se laterals are perpendicular, but are attached to obliquely 

 curving plates, long and narrow, each plate being detached. 

 There are about thirteen of these laterals, in almost straight hori- 

 zontal lines, on both sides of the median line. Theuncini change 

 abruptly from the laterals, ate m oblique rows, are attached to 

 n pi; oblong plates, square at top and base, diminishing as tin v 

 pass oil' laterally ; the uncini arc rather square, their broad, simple 

 apices are armed with three stn enticles, the inner denticle 



In-MIL' the ; 



Th'- I; its tWO rOWfl Of Centrals with the laterals to 



it o| the median line ami a few nm-ini. The upper line . ,f 



the central, the grsl two laterals, one of the uncini, 

 and oi n profile, all detached. 



I' i teeth of this membrane are so nearly on a plane as to allow 



ph to bring out all the details. 



