1 ‘ 2 ACTINOrTERTGir. 
II. Small scales between scutes. 
Trunk completely covered with scutes 
and small rbomboidal scales ; 
dorsal fin occupying the greater 
part ol the back, and anal fin . 
opposed to its binder portion . . Pelargorhynchus (p. 1 
Genus DERCETIS, Agassiz. 
[Neues Jahrb. 1834, p. 389.] 
External bones slightly ornamented with short ridges and rows 
of tubercles. Teeth in form of small, slender, hollow cones, more 
or less clustered. Vertebrae between 50 and 60 in number. Pel^ ,c 
fins arising nearer to the pectorals than to the anal ; dorsal n 
occupying the greater part of the back ; anal fin opposed to t m 
hinder part of the dorsal ; caudal fin forked. Most of the derma 
scutes considerably expanded, and the adjoining longitudinal series 
often in contact ; a paired series along the dorsal and ven 
borders, and another along the lateral line ; no interme w 
squamation. 
Dercetis scutatus, Agassiz. 
1834. Dercetis scutatus, L. Agassiz, Neues Jahrb. p. 390, and Foiss 
Foss., Feuill. p. 20. g 
1844. Dercetis scutatus, L. Agassiz, Foiss. Foss. vol. ii. pt. u. p- - 
Type. Nearly complete fish ; Palaeontological Museum, Munich*^ 
The type species, attaining a length of about 0'35. Leng ^ 
head with opercular apparatus equalling about one fifth of the o 
length of the fish (including caudal fin). Pectoral fins much 
than the pelvic fins, these two pairs separated by a space a 
equal in length to the cranium ; dorsal fin, with about 50 
arising well in advance of the pelvic fins ; anal fin, with not cs 
than 16 rays, opposed to the hindermost part of the dorsal. D e 
scutes ornamented with fine tnberculations, and the three lon 0 i 
tudinal scries on each side almost or completely in contact. 
Form. S( Loe. Upper Cretaceous : li.iumberg, Westphalia. 
Not represented in the Collection. 
The following specimens from the English Chalk probably belo & 
to Dercetis , but are not specifically determined : — 
31075 - 82 . Imperfect anterior portion of a large fish, compri 
the head, clavicle, abdominal vertebrae, man} ^es’ 
preserved scutes, and one of the expanded pelvic ^ 
Chalk, Gray 8, Essex. The cranium measures about 
