CESTRACIONTIDA;. 25? 
There is still some doubt as to the propriety of assigning the fol¬ 
lowing specimens to H. doacinus , but the teeth seem to agree most 
closely with those of this species :— 
P. 2196. Crushed remains of the head and dentition, four of the 
teeth shown, of the natural size, in PI. X. figs. 10-14; 
Lower Lias, Lyme Regis. Most of the teeth preserved are 
referable to the principal lateral rows, and are scarcely 
distinguishable in form from the typical teeth of H. doa¬ 
cinus. The superficial coronal wrinkles are numerous in 
all but few examples, and they are sometimes more closely 
arranged and prominent on one side of the crown than on 
the other. Egerton Coll. 
39785. Small group of anterior teeth, two shown, of the natural 
size, from the posterior and anterior aspect respectively, in 
PI. X. figs. 8, 9 ; Lyme Regis. Purchased , 1862, 
Hyhodus raricostatus, Agassiz. 
1843. Hybodus mricostatus, L. Agassiz, Poiss. Foss. vol. iii. p. 187, 
pi. xxiv. fig. 24. 
Type. Detached tooth; Bristol Museum. 
Teeth with a relatively low crown, the median eminence broad 
and pointed, and all the lateral cones and the lougitudinal crest 
acute ; superficial coronal wrinkles generally few, though variable. 
The hinder lateral teeth are much elongated, with the sharply- 
pointed coronal cusps partially fused together, and the longitudinal 
acute crest especially prominent. 
This species appears to be intermediate between H. doacinus and 
H. delabechei , and it is scarcely possible to distinguish some of the 
teeth from those of the latter species. 
Form. Loc. Lower Lias: Lyme Regis, Dorsetshire 1 . 
43972. A group of very large postero-lateral teeth, many with few 
and insignificant coronal wrinkles. Several of the teeth 
are more elongated than any met with in H. delabechei. 
Purchased , 1872. 
P. 2800. Half of a naturally-arranged transverse series of seven 
large teeth, with few coronal wrinkles, cut across the 
median apices, and the section polished. EnnisTcillen Coll. 
1 A fragmentary tooth, not of H. rciricostatus, is described under this name 
by K. Fricke, Palseontogr. vol. xxii. (1875), p. 393, pi. xxi. fig. 20. 
s 
