Ei;L-KlSIIli.S. 



1011 



ENCHELYMOHPHI. 



Shouhlcr-yirdle detnclictJ aliorc frniii tlic head (Did suspended (it the sides of the spiiud coIkdui Iteh'oid it. No 

 pracoracnideum. Anterior rertehra' iioniud: air-bladder destitute of osseous coviie.rion n'itli the aaditorii apjiaratas. 

 Opercular apparalits complete: lint Ih-- hijomandihidar arch without si/mplerticum. Palatine arch <ind ma.iillarij 



arch incomplete. Ventral fins none. 



Regarded eitlier tVdiii m biological or a morpho- 

 logical point of view the F,nchel\inurph 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- 

 jiliological elucidation of their structure shows the Te- 

 k'osteous type in a singular simplicity, whether this 

 should he 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 I-^el lias a certain resemblance to tiie analogous 

 arrangement in the Ravs and Sharks, tiiough the sus- 

 pensory bones do lutt corres[>ond. Tlie ])osttemporal 

 bone as well as the postclavicular is wanting, the girdle 

 itself consisting on each side only of the clavicle and 

 supraclavicle. The latter of these (fig. '2&a, set), with 

 its flattened, more or less distinctly forked to]i, hangs 

 loose, embedded in the outei'most layei- of the dorsal 

 half of the great lateral muscle, but the clavicle (fig. 

 26.J, el)y which retains its ordinary relation to this 

 muscle, is attached liy 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 aVjdominal vertel)r;e''. Tiie shoulder- 

 gii'dle 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 supi'ascapular part (the 

 upper parts of the (jrimordial shoulder-girdle) being 

 attached to the upper side of the spinal column. In 

 the Eel this resemblance to the cartilaginous fishes is 



consequently of a secondary origin, probably coimected 

 \vith the great development of the branchial cavity, 

 wiiich has forced the shoulder-girdle backwards, loosen- 

 ing its attachment to the cranium, and causing the 

 disappearance of tlie posttemjjoral bone. The girdle is 



Fitf. SilS, 

 in frciit. 

 clavicle : 



Half of llie shoiilder-gircUe in Anyuilla vulgoi-is, seen from 

 o times the natural size, set, left supraclavicle; cl. left 

 . left scapula: cf, left coraecid; i, brachial liones of tlie 

 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 urohvoid bone' (fig. 2(iS, A and 

 fig. '271, I> and (', ah), which is directed backwards, 



" Gr. e'/xeXvs. eel, and fiOQCpr[, form. 



'' 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 duels, belonging to the 

 lateral line, nms under the skin from the head (the temples) to the supraclavicle. 



'■ 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 

 upper surface. Its posterior extremity is more or less deeply divided into three spinous points (fig. 282, p. 103G). 



