12 SHOULDER-GIRDLE AND BREAST-BONE. 



seen, behind and within, the coracoid foramen (fig. 7, c. m.), that is, its entrance : its exit may be 

 seen in the fresh cartilage below the largest glenoid cup. 



It will be seen from the above description that, on the whole, 1 agree with Professor Owen 

 as to the special homologies of the Sturgeon's Shoulder-girdle (see his ' Lect. Comp. Anat./ vol. 2, 

 p. 131, and ' Osteol. Catal. Mus. Coll. Surg.,' vol. 1, p. 83, No. 374) ; but I am not aware whether 

 or no he considers this as an instance of the articulation of the supra-scapula with the lateral 

 occipital region ; if so, then I must be allowed to differ from him. In the work first cited (' Lect.,' 

 p. 131, fig. 43) the dermal bone (d. 50) is a splint of the supra-scapular cartilage (50), and 

 articulates with the great supra-temporal plate (d. 8), as is well shown in Huxley and Hawkins's 

 ' Atlas ' (plate 5, fig. 3 a) ; for the dermal splint of the supra-scapula is the first lateral-line 

 bone, and comes next behind and below the supra-temporal or supra-temporals in all the Fishes 

 that possess such bones. But, as my fig. 7 shows, the true supra-scapula (s.'sc.) lies low down 

 within the great scale that invests it, and is really as free of the occiput as its counterpart in the 

 Placoids : I shall afterwards show that there is no instance whatever in which the true Shoulder- 

 girdle is articulated to the occiput. All the confusion in this matter is due to Cuvier's misinter- 

 pretation of the first lateral-line bone (my " post-temporal scale") as the supra-scapula ; and 

 on this nail, which could not be driven into Nature's hard wall of facts, our great English 

 anatomist hung his theory of " the Nature of Limbs." 1 



Professor Huxley, in his ' Elements of Comparative Anatomy' (1864), gives a drawing (after 

 Miiller) of the anterior part of the head-skeleton of the Sturgeon, in which the Shoulder-girdle is 

 left out (see p. 206, fig. 83) ; this wood-cut shows that there has been no violence done to the 

 head by the removal of cartilages so loosely and extraneously connected with it. On the same 

 page we are referred to another figure (82, p. 205) in which an outline view of the dermal plates 

 of the Sturgeon's head is given, the cartilage below being shown by shading. Here the plate / 

 is called a " supra-scapular bone," and L the " scapula :" this seems to me to be a mistake, for the 

 latter is the splint to the supra-scapular cartilage, and the former is merely a huge " supra- 

 temporal." 2 



If the reader refers to Plate I, figs. 6 8, he will see the relation of the supra-scapular splint 

 (p. t., " post-temporal ") to the soft endo-skeletal supra-scapula within it ; if it is compared 

 with the figures in Plate II, it will be easily seen that this dermal bone is the true homo- 

 logue of the so-called " supra-scapula " of the Teleostei : in them, however, there is no endo- 

 skeletal piece in the inside ; the supra-scapula being entirely absent, as far as I know, in 

 all Pishes except the Placoids and the Sturgeons. The upper fork, and all the posterior margin 

 of the " post-temporal " scale of the Sturgeon, is devoid of the " ganoid " prickly ridges (see figs. 

 6 and 8) ; this smooth thin part being subcutaneous to a great degree, or at least formed by 

 ossification of the innermost part of the " cutis vera." The well-macerated specimen from 

 which these drawings were made has revealed the true scapular splint, the bone which in osseous 



1 A Discourse delivered on Friday, February 9th, 1849, at the Royal Institution of Great Britain, 

 and published by Van Voorst, London. Our author still refers us to this work as containing his 

 views of the philosophy of these great questions (see ' Zool. Trans./ vol. vi, part i, p. 45, 1866). 



~ There are several other points in the Fish's skeleton in which I differ from my friend Professor 

 Huxley (see p. 188 of the same work; and also p. 162 of my paper " On the Ostrich's Skull," ' Phil. 

 Trans.,' 1866). 



