196 



PROCEEDINGS OF THE ACADEMY OF 



Lingual membrane (pi. V., fig. 7) long and narrow. Teeth 

 23 1 23, with 11 perfect laterals. Centrals with a quadran- 

 gular base of attachment, higher than wide. Reflection about 

 half as long as this base, with along, narrow median cusp reaching 

 the lower margin of the base of attachment, beyond which pro- 

 jects slightly the short cutting point ; side cusps but little de- 

 veloped, but bearing short, stout triangular cutting points. Late, 

 rals like the centrals, but unsymmetrical by the suppression of the 

 inner, lower, lateral angle of the base of attachment, and the inner 

 side cutting point. First marginal (b) with a square base of 

 attachment, broadly reflected into one stout cusp, bearing a single, 

 stout, very long, bluntty ending, oblique cutting point. Outer 

 marginals (c) low, wide, the reflection broad, reaching the lower 

 edge of the base of attachment, and bearing one inner, long? 

 oblique, blunt cutting point; there appear no outer, small, side 

 cutting points. 



Genus PALLIFERA, Morse. 



Jaw stout, arcuate, ends but little attenuated, blunt : anterior 

 surface with stout separated ribs, 9 in P. dorsalis (fig. 42), over 



15 in P. Wetherbyi. The jaw of the 

 latter is arched, and has a blunt me- 

 dian projection, broken by the ends of 

 the ribs. These last are more irregu- 

 larly developed also. 



Fig. 43 shows the arrangement of 

 the teeth on t'he membrane in P. dor- 

 salis, while separate teeth of the same species are more correctly 

 drawn on pi. VI., fig. C. 



Fi?. 42. 



Jaw of Tebennophorus dorsalis ! 



Fig. 43. 



Lingual dentition of Pallifera dorsalis. 



Mr. Morse gives 115 rows of 56 1 56 teeth each, with 13 

 perfect laterals. In the specimen examined by me I found only 

 29 1 29 teeth, with 14 perfect laterals, a difference sufficiently 



