THE SHOULDER-GIRDLE IN FISHES. 51 



inwards. The supra-clavicle is styloid below, and has three retral spines above, like the sub-marginal 

 spines, above and below the body of the Fish ; these spines are separated by sharp notches. The 

 clavicle (cl.), which is deeply sulcate at its outside above, for the supra-clavicle, is an extremely 

 long bone, and withal very strong ; it is bent on itself, at a few degrees more than a right angle, 

 at the junction of its upper and middle third, and behind the bend there is a sharp spine, which 

 looks upwards. Below this spine there is a triangular plate, which overlaps the post-clavicle (p. cl.) ; 

 above the spine this dense bone is flat on the outside, smooth, and semi-cylindrical within. Below 

 the bend the bone is curved gently backwards, and is divided by three deep sulci into three strong, 

 smooth wings an antero-internal, an antero-external, and a posterior ; the antero-internal, from 

 its upper half, sends backwards a fourth plate, the innermost, which reaches only half way down. 

 The three main wing-tracts are continued to the bottom of the bone, where it is tied to its 

 fellow of the opposite side. The post-clavicle (p. cl.) is spatulate at the top ; then thick, strong, 

 four-edged, and grooved deeply in front and behind ; it meets its fellow of the opposite side, at a 

 great distance from the clavicle ; yet it is set on to the inside of that bone by much less than a 

 right angle. This bone is like that of the Balistidse, and so are many other parts of the 

 skeleton of this strange-looking Fish ; and I am of opinion that this type is the nearest point 

 of meeting of the Acanthopteri with the Plectognathi. The scapula (sc.) is typical, but its 

 " fenestra" is finished in part by cartilage ; there is also a considerable tract of cartilage between 

 it and the coracoid. The scapular part of the glenoid region receives the three upper brachials 

 and part of the lowest (b. 1 4). The coracoid, deprived of its inter-clavicular alae, would be an 

 elegantly adze-shaped bone ; its prae-coracoid part (p. cr.) is a quadrant, with a cartilaginous 

 selvedge along its rounded supero-anterior edge; this edge and the front margin of the scapula 

 are partly hidden by the posterior plate of the clavicle. The hinder and lower margins of the 

 prse-coracoid are very thick ; where these thick edges meet, the body of the coracoid has been 

 reduced to a small isthmus of cartilage ; but it gradually increases to an exquisitely rounded, 

 delicate, subarcuate rod downwards. This rod is invested by a very dense, highly polished 

 ectosteal sheath, which does not quite reach the base of the clavicle ; but the free cartilaginous 

 end of the coracoid does gain the abdominal line. The nerve-foramen (cr. fo.) is seen where the 

 body of the coracoid is most attenuated ; behind this passage the posterior inter-clavicular wing 

 sends upwards a blunt spine ; this narrow ala only reaches half way down, and it is curved a 

 little outwards. The anterior inter-clavicular wing is very large, and occupies two thirds of the 

 front of the coracoid rod ; it is crenate, with notches of various sizes in front, lies a small 

 distance from the posterior wing of the clavicle, and its junction with the lower edge of the 

 prae-coracoid can be clearly seen above ; yet there was but one ossification for the whole coracoid 

 originally, as far as I can make out. The whole of the coraco-scapular plate is gently convex 071 

 the outside. There are four brachials (b. 1 4) ; they increase in size, both as to length and 

 breadth, from above downwards ; they have the hourglass-shaped outline, are very long, and are 

 unossified at both ends. 



Example 2. Lampris guttatus, Retz., Cuv. 



The skeleton of the Opah, to be seen both in the Hunterian and British Museums, is well 

 worthy the study of the anatomist who would understand the relation of the subcutaneous 

 splints to the endo-skeleton ; in it they are both developed in a very extraordinary manner. 



