EEL-FISHES. 
1011 
ENCHELYMOKPHI. 
Shoulder-girdle detached above from the head and suspended at the sides of the spinal column behind it. No 
prcecoracoideum. Anterior vertebrae normal: air-bladder 
Opercular apparatus complete; but the liyomandibular 
arch, incomplete. 
Regarded either from a biological or a morpho- 
logical point of view the Enchely morph series is one 
of the most remarkable among fishes. The life of the 
Eels, especially their sexual life, though studied for 
thousands of years, was shrouded in a veil of mystery 
to a time within the memory of man; and the mor- 
phological elucidation of their structure shows the Te- 
leosteous type in a singular simplicity, whether this 
should be explained as a primordial condition or as a 
retrogression in the direction of older types. 
The suspension of the shoulder-girdle in our com- 
mon Eel has a certain resemblance to the analogous 
arrangement in the Rays and Sharks, though the sus- 
pensory bones do not correspond. The posttemporal 
bone as well as the post-clavicular is wanting, the girdle 
itself consisting on each side only of the clavicle and 
supraclavicle. The latter of these (tig. 265, set), with 
its flattened, more or less distinctly forked top, hangs 
loose, embedded in the outermost layer of the dorsal 
half of the great lateral muscle, but the clavicle (fig. 
265, cl), which retains its ordinary relation to this 
muscle, is attached by means of an horizontal tendon 
(a part of the aponeurosis between the dorsal and 
ventral halves of the lateral muscle) to the sides of 
the fifth and sixth abdominal vertebrae 6 . The shoulder- 
girdle is similarly suspended, behind the head, in the 
said cartilaginous fishes; but an essential difference con- 
sists in the absence of both clavicle and supraclavicle 
in the last-mentioned forms, the suprascapular part (the 
upper parts of the primordial shoulder-girdle) being 
attached to the upper side of the spinal column. In 
the Eel this resemblance to the cartilaginous fishes is 
destitute of osseous connexion with the auditory apparatus, 
arch without symplecticum. Palatine arch and maxillary 
Ventral fins none. 
consequently of a secondary origin, probably connected 
with the great development of the branchial cavity, 
which has forced the shoulder-girdle backwards, loosen- 
ing its attachment to the cranium, and causing the 
disappearance of the posttemporal bone. The girdle is 
Fig. 265. Half of the shoulder-girdle in Anguilla vulgaris , seen from 
in front, 3 / 2 times the natural size, scl, left supraclavicle; cl, left 
clavicle; sc, left scapula; cr, left coracoid; b, brachial bones of the 
left pectoral fin. 
completed below by the ligamentous connexion between 
the two clavicles, which are curved at an obtuse angle; 
and this lower part of the girdle is joined by a long 
muscle to the short urohyoid bone c (fig. 268, A and 
fig. 271, B and C, uh), which is directed backwards, 
a Gr. ey%ehv g, eel, and fiogcpf form. 
b In our Conger the shoulder-girdle is suspended in the same manner and at the same point, but still more superficially, with the 
upper parts nearer to the skin. The posttemporal bone is thus wanting there as well; but a row of cartilaginous ducts, belonging to the 
lateral line, runs under the skin from the head (the temples) to the supraclavicle. 
c In our Conger the urohyoid bone is longer, but preserves the ordinary Teleosteous type, being flattened only at the base, where it 
articulates with the basihyoid bones (coalescent, as in the common Eel, with the ceratohyoids), and furnished with a raised median keel on its 
Tipper surface. Its posterior extremity is more or less deeply divided into three spinous points (fig. 282, p. 1036). 
