328 
SELACHTT. 
or four in number and small ; base-lino of crown gently arched. 
Supposed lower anterior teeth very minute, with well-separated 
lateral cusps. 
Form. ^ Loc. Chalk : Kent. 
36908. Type specimen, described, with a very imperfect figure, by 
llackie, loc. cit. ; Lower Chalk, Dover. Farchased, 1862. 
41675. Nearly complete mandibular and hyoid arches, with a por- 
tion of the right (? upper) dentition, and a few teeth on 
the left, described and figured by the present writer, Proc. 
Zool. 8oc. 1886, p. 218, pi. xx. ; Kent. The pterygo- 
quadratc measures about 0'075 in length, and exhibits a 
facette for a postorbital articulation with tho cranium; 
the hyoid arch is notably slender. An anterior tooth, 
probably of tho upper jaw, is shown, of three times tho 
natural size, in PI. XI. fig. 17, and a posterior tooth, 
similarly enlarged, in fig. 20. Touhnin Smith Coll. 
47287. Fragments of cartilage associated with shagreen and a few 
teeth ; I.owor Chalk, Dover. One tooth, representing 
about tho fourth lateral series, is shown, of three times 
the natural size, in PI. XI. fig. 18, and another, of about 
tho sixth series, similarly enlarged, in PI. XI. fig. 19. 
I ho shagreen -granules are marked by prominent ridges, 
terminating in a dcnticulateil margin. Gardner Coll. 
41909. Fragments of jaws, with a few teeth, mostly of tho upper 
anterior scries ; (?) Burham. Mrs. Smith's Coll. 
49032. Imperfect remains of the head, pectoral arch, and the ante- 
rior half of tho vertebral column, exposed from beneath, 
noticed by tho present writer, Proc. Zool. Soc. 1886, 
p. 223. The base of tho cranium exhibits a longitudinal 
raised line, evidently the remains of the primitive invest- 
ment of the notochord ; each half of the pectoral arch is 
long, slender, and tapering distally; and tho vertobrm are 
astorospondylic, a few being shown, of the natural size, in 
PI. XII. fig. 6. Mrs. Smith's Coll. 
43124. Anterior upper tooth ; Gravesend. Weiherell Coll. 
P. 4100. Minute anterior upper tooth, doubtfully referable to this 
species; near Margate, Kent. 
Presented hy Sydney C. Cocleerell, Esq., 1 883. 
49960. An imperfect aiitero-lateral tooth, doubtfully referable to 
S. duhrisiensis ; Glyndo, Sussex. Caj^ron Coll. 
