432 
ACTINOPTERYGII. 
some extent in advance of the anterior extremity of the mandible; 
the pointed front end of the dentary bones suturally united with 
a deep re-entering angle in the presymphysial bone; superficial 
ornament consisting of delicate rugae. Vertebrae in the form of 
separated narrow rings, much deeper than broad. Scales smooth 
or feebly tuberculated and rugose ; those of the lateral line not 
much exceeding in depth the series below. 
The vertebral rings in this species evidently differ from those of 
the preceding species merely in the circumstance that they repre¬ 
sent a lower stage of calcification than the elongated constricted 
rings already described. This is indicated by the considerable 
width of the spaces between the successive rings. 
Form. Sj' Loc. Lower Kimmeridgian : Bavaria, and (?JAin, France. 
35014. Head and greater part of the trunk with paired fins, the 
head shown of the natural size in PI. XVII, fig. 12; 
Lithographic Stone, Solenhofen. The specimen is ex¬ 
hibited in side view, displaying the shortness of the 
mandible, the suture separating the presymphysial bone 
(ps.) from the dentary (d.), and the proportions of the 
opercular apparatus. The fins are fragmentary, and the 
. scales are mostly shown in obscure impressions. 
Purchased , 1860. 
36029. Contorted fish showing the principal specific characters, 
including the incomplete calcification of the notochordal 
sheath in the form of deep and narrow separated rings ; 
Solenhofen. Purchased, 1861. 
P. 962. Imperfect specimen showing the head and greater part of 
the trunk with pectoral fins chiefly in impression ; Solen¬ 
hofen. Egerton Coll. 
P, 962 a. Detached skull and mandible, much crushed, showing 
the superficial rugose ornament, some of the teeth in the 
lower jaw, and the suture between the dentary and pre¬ 
symphysial bone ; Solenhofen. Egerton Coll. 
P. 2001. Two imperfect specimens chiefly in impression, probably 
of this species ; Cirin, Ain, France. The dorsal ridge- 
scales in one specimen are coarsely rugose. Egerton Coll. 
The following imperfect specimen appears to exhibit a snout as 
much attenuated as that of Belonostomus tenuirostris , but the fish 
is of larger dimensions than usual in this species and the squamation 
has more nearly the aspect of that of B. muensteri. The specimen 
