PIKE-FISHES. 
997 
ESOCIFOKMES. 
Physostoms ivith 
bones. The first four abdominal 
without connexion ivith the cranial 
opercular apparatus. 
The Esociform series corresponds to the order 
established, under the name of HaplomP, by Cope 6 . 
It includes the Pikes ( Esocidat ), the Mud-Minnows 
( Umbridce , named after the Austrian and Hungarian 
dogs-fislT ), the Toothed Carps ( Cyprinodontidce — see 
above, p. 702 — three species of which family occur 
in Southern Europe), and the Blind-fishes ( Heter - 
opygii , inhabitants of caves and brooks in North Ame- 
rica, a family whose maxillaries, like those of the 
Toothed Carps, form no part of the margin of the 
mouth, and which is especially distinguished by the 
forward situation of the vent, in front of the pectoral 
Teleosts, from the head , and without precoracoid 
development. Air-bladder , where present , simple , 
and pterygopalatine arches complete , as well as the 
No adipose fin. 
fins). In the Scandinavian fauna the series is repre- 
sented by the first-mentioned family alone. 
The series contains very dissimilar forms, predatory 
fishes like the Pikes, and more harmless fishes of small 
size, principally insectivorous or even mud-eaters. This 
dissimilarity manifests itself, as usual, most clearly 
in the form of the head and especially of the mouth. 
In addition to the above-given characters, hotvever, 
the series has a peculiarity characteristic of the great 
majority among its members in the backward posi- 
tion of the dorsal fin, which lies above or even behind 
the anal. 
the shoulder-girdle suspended , as usual in the 
vertebrae normal in form and 
cavity. Hyomandibular 
Maxillaries fully developed. 
Fam. ESOCIDiE. 
Dorsal fin situated , at least for the greater part , behind the perpendicular from the vent, 
depressed, and, long (at, least a.s long as the postorbital part of the head or only a little shorter), 
upper jaw formed by the tip of the ethmoid bone , the intermaxillaries, and the maxillaries. 
canine teeth. The pneumatic duct of the simple air-bladder runs 
The family of the Pikes differs considerably from 
the preceding family: a Pike and a Herring have not 
much in common. But one of the most characteristic 
external peculiarities of the Esocoid family, the caudal 
position of the dorsal and anal fins, reappears in a 
Mediterranean fish Alepocephalus, the type of a family 
very nearly allied to the Herrings, and also in the 
above-mentioned Paralepidince. The more predatory 
instincts of the Pikes, however, accompanied as they 
are by a simplification of the intestinal canal, the py- 
loric appendages having entirely disappeared, range 
these fishes nearer to the Salmonoids, in spite of the 
numerous pyloric appendages of the latter. The lateral 
Gape large. Snout 
Margin of the 
Mouth f urnished with 
from the anterior part thereof to the oesophagus. 
margins of the upper jaw are also formed almost as 
in the Salmonoids — short, toothed intermaxillaries (fig. 
253, C and F , pmx) and long, though here toothless, 
maxillaries ( mx ), each with a well-developed supple- 
mentary bone (j) — but show a pecularity which we 
have not seen in the preceding fishes, and which is all 
the more important, from a systematic point of view, 
to the explanation of the forms immediately following 
this family. The intermaxillaries, which we have 
hitherto found to be more or less closely applied to 
each other at the tip of the snout, are here (fig. 253, 
C , pmx) separated by the cartilaginous end of the 
ethmoid bone (tig. 253, A, C, and E, etcr), which 
“ arckoog, simple and loyog , shoulder; i. e. without precoracoid in the shoulder-girdle. 
b Trans. Amer. Philos. Soc., Philad., n. ser. vol. XIV (1871), p. 455. 
c Heckel and Kner: Susswasserf. Ostreich. Mon., p. 291. 
