196 PROCEEDINGS OF THE ACADEMY OF 
Lingual membrane (pl. 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 a long, 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 (0) with a square base of 
attachment, broadly reflected into one stout cusp, bearing a single, 
stout, very long, bluntly ending, oblique cutting point. Outer 
marginals (¢) 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 the membrane in P. dor- 
salis, while separate teeth of the same species are more correctly 
drawn on pl. VL., fig. C. 
Jaw of Tebennophorus dorsalis ! 
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 
