548 H. H. SWINNERTON. 



distally spicular^ lyi"g along the inner surface of the palatine ; 

 its antero-veutral ray is the smallest^ aud lies on the anterior 

 edge of the quadrate^, thus occupying the position of an 

 ectopterygoid (Parker's pterygoid) ; its posterior ray, which 

 is the largest, lies along the inner side and upper border 

 of the quadrate, and thus functions as an entopterygoid 

 (Parker's mesopterygoid). Possessing, as it does, all these 

 complicated relationships, there is some difficulty in ascertain- 

 ing its homologies. The position of its largest portion, in 

 relation to the inside aud upper border of the quadrate, 

 strengthens the probability that it represents the entoptery- 

 goid. 



From these details it will be seen that Huxley (58, p. 409) 

 was correct in his delineation aud description of the position 

 and origin of the hyomandibular, symplectic, operculum, 

 metapterygoid, and mandibular bones, but that he overlooked 

 the true palatine and mistook the pterygoid for this. 



Adult. — There is little to record concerning the branchial 

 apparatus (fig. 22) beyond the appearance of a centre of 

 ossification in each hypobranchial ; the more complete ossifi- 

 cation of all the parts ; the formation on the fourth epibran- 

 chial of a small ascending process which at its apex meets 

 the corresponding one on the third (br. e.3) ; and the shifting 

 of the insertion of the hypobranchials belonging to the third 

 and fourth arches from the sutures between the basibranchials 

 on to these themselves. 



Cope (70) observed that the pharyn go-branchial s were small 

 in accordance with the general tendency of the whole apparatus 

 to become weak ; he also pointed out (p. 457) that they bear 

 a close resemblance to those of Belone. The first, present in 

 so many Acanthopterygii as a styloid bone, frequently called 

 the suspensory pharyngeal, is quite absent in both these 

 fish. 



At Stage IV. the ceratohyal was equal in size to the epihyal 

 {hy. e.), but now, owing to a considerable increase in 

 length, it seems to bear the latter like an epiphysis at its 

 upper end. 



