cEsTKAcroiniiD^, 
257 
There is still some doubt as to the propriety of assigning the fol- 
lowing specimens to II. 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, L}'me Eegis. Most of the teeth preserved are 
referable to the principal lateral rows, and are scarcely 
distinguishable in form from the typical teeth of II. doa- 
cinm. 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. E<jtrton Coll. 
39785. Small group of anterior teeth, two shown, of the natural 
size, from the posterior and anterior aspect respectively, in 
ri. X. figs. 8, 9 ; Lyme Eegis. Purchased, 1862. 
Hybodus raricostatus, Agassiz. 
1843. Hybodus raricostatus, 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 longitudinal crest 
acute ; superficial coronal wrinkles generally few, though variable. 
The hinder lateral teeth are much elongated, with the sharifiy- 
pointed coronal cu8i« partially fused together, and the longitudinal 
acute crest especially prominent. 
This species appears to bo intermediate between //. doacinus and 
H. delahediei, and it is scarcely possible to distinguish some of the 
teeth from those of the latter species. 
Form. Sf J^oc. Lower Lias: Lyme Eegis, Dorsetshire*. 
43972. A group of verj- largo postero-lateral teeth, many with few 
and insignificant coronal wrinkles. Several of the teeth 
are more elongated than any met with in II. delahechd. 
Purchased, 1872. 
P. 2800. Half of a naturall 5 '-arranged transverse series of seven 
large teeth, with few coronal wrinkles, cut across the 
median apices, and the section polished. EnnisJeUUn Coll. 
* A fragmentary tooth, not of II. raricostatus, is described under this name 
by K. Fricke, Paleeontogr. vol. xxii. (1875), p. 393, pi. xxi. fig. 20. 
