244 FOSSIL REMAINS OF HYBODUS 
cal studs, each of which is ‘attached by a néck toa round and 
expanded base, (fig. 6, 6 & c). “The stitface'of these dermal 
points is marked’ with’ very prominent’ cosfe, and their sub- 
stance appears to be éxactly analogotis to’ that ofi the teeth: 
The portion of the skin of Acrodis, an allied genus, figured 
in. Dr. Buckland’s' Bridgewater’ Tréatisé, seenis ‘to present a 
closely analogous character. 
_. Notwithstanding ' that the’ teeth’ in this specimen are‘ very 
numerous, and for the most part implanted in the bone by their 
original attachments, T have béen quite imable to form anidea 
respecting the character which the entixe jaws would present, 
and the relations which they ‘have borne to’ the surrounding 
parts. The fragments of jaws figured by Agassiz; throw no 
light upon this matter; ‘and althowgh° in the* Poissons Fos- 
Sils’ a great ‘many species aré’! Characterised “by the’ osseous 
spines, ‘and the ‘genus’ often alltided ‘to! in’ the remarks upon 
Ichthyodorulites, the complete history’ of its ‘characters and 
probable affinities ‘has ‘as’ yet been postponed.” ! 
Iam not able to determime whether the two'frasments' fi- 
guted belong to one and the saitie side’ of the mouth, ‘or to 
the upper and lower jaws! there is nothing like‘a symphiysis, 
nor.at ‘the ‘termination Of the'rows do’ thé teeth present! any 
decided ‘diminution in size or number, by which the position 
of the lateral ligamental ‘articulations might ‘be detected.— 
The series of teeth on’ the latget ‘fragtient consists of seven 
rows, six deep, disposed! along’ the’ anterior’ ‘border of! the 
‘mass; at one extremity the Continuity of the’series being in- 
_terrupted by the fractured Tatetal ‘edge or border of ‘the mass 
itself: the rows of teeth aré contintied nearly tothe margin of 
_the opposite Jateral border, But héié they make a'sudden bend 
inwards ‘and backwards, by which ‘their ‘continuity is’ pre- 
“served ; the portion ‘so recurved Consikts’of five! additional 
‘Tows, and its termination about the certre! of the mass is 
shown in ‘the: figure.” Reasoning front the“ analogy of the 
jaws in the existing génera of sharks, and “also ‘fromthe ap- 
parently forcible ‘displacenient of the’ teeth’ at the immediate 
“Spot where the bend occurs, ‘this suddén' ctirve wouldappear 
to be the résult of accident, ‘rather than the’ natural disposi- 
tion of the parts.” The ‘smalls fragnient) however exhibits a 
‘yery similar and equally sudden alteration in ‘the’ ditection of 
the rows of teeth, and the Sanie thing may We! observed in the 
original jaw figured. by M. de’ la Beché in ‘the’ * Geological 
Transactions.’ a : 
ext believe the ] 2th livraison of the ‘Poissons Fossils’ is very shortly ex- 
pected, and it may possibly contain the history of the genus Hybodus. 
