THE SHOULDER-GIRDLE IN FISHES. 53 



Fam. 



Examples. Morrhua vulgaris, Cuv. ; Morrhua (eglefinus, Cuv. ; Merlangus vulgaris, Cuv.; 

 Merlucius vulgaris, Cuv. 



The shoulder-splints of the Cod, Whiting, and Hake are quite normal as to strength ; but the 

 stoutish post-clavicle is single. The knife-like supra-clavicle and the large clavicle of the Cod 

 are well shown in Huxley and Hawkins's ' Atlas ' (pi. xi, figs. 12 a and 12 b) ; it is seen in these 

 figures how that the true Shoulder-plates (b c) are only half the length of the clavicles (a). In 

 the Cod (Morrhua vulgaris}, and still more in the Hake (Merlucius vulgaris}, the post-branchial 

 part is narrow, but thick ; the antero-external lamina, especially in the Hake, lies quite externally, 

 close under the skin of the Fish's side. 



The posterior lamina of the clavicle is turned inwards, and only serves for the attachment of 

 the scapula and prse-coracoid ; it passes outside them (see 'Atlas,' fig. 12 b). In the Whiting 

 (Merlangm vulgaris) the bones are similar to those in the Cod ; they are very delicate and thin, 

 but well ossified. In the Haddock (Morrhua (eglefinus), however, the splint-bones are all 

 extremely solid, approaching in this respect the " os petrosum " of the Mammalia. In this latter 

 Fish the spine of the post-temporal is long and delicate, but the head of the bone is very massive ; 

 the supra-clavicle is a stout nail, with an oblique head ; and the clavicle, stout throughout, is, in 

 its lower half, a solid, thick spindle of bone. The post-clavicle, which is single and large in all 

 the Gadidee, is stoutest in the Haddock; in all the head is dilated and hooked. The 

 scapula of the Gadidse differs from that of the typical Fish, in having the fenestra (c. s. f.) 

 common to it and the coracoid (see Plate II, fig. 15, c. s. f.) ;' but the most important thing to 

 be noticed is in the differentiation of the cartilage into three rays a division first marked out in 

 the Skate (Plate I, fig. 2), but more clearly to be seen in certain Lizards, e.g. the Iguana. 

 This triple condition of the coracoid in the Cod-tribe is partly masked by periosteal growths, that 

 fill up the angle of the " notch " between the meso-coracoid and the coracoid ; and the lower part 

 of the " fenestra," which belongs partly to the scapula, and originally extended downwards to the 

 common point of union of the three rays of the coracoid. If the reader will hold the macerated 

 coracoid of a Haddock up to the light, he will see the triangular pra3-coracoid, the narrower 

 meso-coracoid broadest in front, and the long, delicate coracoid proper. Between these is to 

 be seen the thin, intervening, periosteal spaces ; the upper filling-up the pointed, lower part of the 

 "fenestra;" the middle one in the almost right-angled space between the meso-coracoid and 

 coracoid ; and the large " posterior inter-clavicular wing," which rises up below the lowest 

 brachial (Plate II, fig. 15, b. 4), and runs to the bottom of the rod in the Cod and the Haddock. 

 In the Hake (Merlucius} the parts are all slenderer; the coracoid, especially, is extremely 

 delicate (twice as long as in the other Gadidae), and has its "wings" only half the length 

 of the rod out of which they grow. The thick, stout brachials are somewhat hourglass-shaped ; 

 there are four of them, and they increase in size from above downwards. 



The soft-finned Fishes (Malacopteri) that go to form Muller's Order Physostomi will 

 bear considerable subdivision ; yet it is easy to see that the Apodal types should form a 

 Sub-order (see Owen's ' Lectures,' vol. ii, p. 48) ; but the Siluroids, which I have already 

 treated of, ought certainly to make a Sub-order by themselves. Then, as far as my part of the 



