IIG Transactions. — Zoology. 



and containing thirty-four ossifications. The first arch has 

 the four usual elements. The pharyngobranchials of the 

 second, third, and fourth arches are broad and articulated into 

 one rough mass above the pharynx. The third hypobranchial 

 has a small ventral hook partially enclosing, with its fellow, 

 the ventral aorta, while the fourth arch has no hypobranchial. 



The fifth arch consists on each side of a single lower 

 pharyngeal bone with fine villiform projections. The copulas 

 are : First, a long cartilage-tipped ossification, lying mainly 

 between the first hypobranchials. The second separates the 

 second and third -hypobranchials ; its anterior third is cartila- 

 ginous. Sometimes there is a small nodule — copula 3 — 

 separating No. 2 from No. 4, a diamond-shaped cartilage 

 touching the third hypobranchials by its anterior borders, and 

 the fourth ceratobranchials by its posterior edges. The paro- 

 steal gill-rakers, movably attached, are short and dagger-like, 

 and occur as far back as the front border of the fourth arch. 



6. Pectoral Girdle.- — The pectoral girdle is very strongly 

 developed ; its ventral moiety is carried far forward to be 

 vertically beneath the orbit, behind and below the urohyal, 

 and its anterior edge is largely hidden by the operculum and 

 branchiostegal membrane. The post-temporal, unforked and 

 triangular, is firmly fixed by its sculptured surface to the 

 auditory region of the skull : with the opisthotic it forms 

 a good socket for receiving the head of the supra-clavicle. 

 The latter, strong and rectangular, covers a long vertical pro- 

 cess of the clavicle, and below enters a groove on that bone. 

 The clavicle, the largest bone in the body, forms a curve with 

 its convexity downwards and backwards. The anterior pro- 

 cess of its forked dorsal end abuts against the opisthotic 

 process. The outer surface presents a long ridge, expanded 

 into a granular disc in its upper half. The inner surface also 

 has a long ridge, which forms a strong connection with the 

 upper anterior end of the pelvic girdle, and which in front 

 forms a low rectangular area immovably articulated with its 

 fellow of the opposite side. The clavicle bears two post- 

 clavicles, the upper a small plate carrying the styliform lower 

 bone. The scapula, perforated by a foramen, is a small 

 rhomboid partially interposed between the posterior end of 

 the coracoid and the clavicle. The hatchet-shaped coracoid 

 covers immovably, by the anterior end of its flattened handle, 

 the front of the clavicle, and its posterior border is not 

 indented. The four brachials, carrying each two fin rays, are 

 borne equally by the scapula and the coracoid. 



7. The Pelvic Girdle. — The pelvic girdle (or basiptery- 

 gium?) consists of a pair of very strong ossifications uniting by 

 two symphyses, and interposed wedgelike, by a mobile connec- 

 tion, between the two clavicles. Each bone consists of two 



