OSTEOLOGY, ETC., OF SYNGNATHUS PEGKIANUS. 639 



orbital s. To this bone I propose to give the same name, 

 although it is much larger, and extends farther forward, leaving 

 the orbital region altogether, and thus loses to a certain extent 

 the claim to the name. It is largest in the orbital region (fig. 

 11), and then constitutes the outer bone of the snout; more 

 anteriorly (fig. 12), however, it becomes, as it were, thrown 

 down towards the under surface of the snout, and gradually 

 becomes smaller, terminating slightly in front of the posterior 

 extremity of the quadrate. 



Appearing in the series of transverse sections^ in the nasal 

 region, about the same time as the quadrate, is a bone (fig. 12 

 Mpt.), which I am inclined to refer to the pterygoid series, 

 probably the metapterygoid. Posteriorly, as in the bones 

 above described, no trace of cartilage is present, but near its 

 anterior extremity it appears, and is there seen to be continuous 

 with that of the quadrate, so that the eetosteal bone would 

 correspond to the posterior process of the pterygo-quadrate 

 cartilage of the young stages. It passes forward as far as the 

 mouth, becoming gradually smaller anteriorly, just as the 

 quadrate becomes broader. Posteriorly it articulates with the 

 upper portion of the symplectic in its broad region. It has the 

 appearance of a scale, separated from the symplectic by a 

 quantity of muscular tissue. At first sight one would not be 

 inclined to identify this bone as the metapterygoid, on account of 

 its great separation from the hyomandibular, since it is generally 

 described in connection with that bone to which it usually 

 forms a buttress. From its origin, however, one would be rather 

 inclined to imagine it having a much closer relation with the 

 quadrate than the hyomandibular, which belongs to the suc- 

 ceeding arch, and this we find to be the case here. The great 

 elongation of the symplectic has carried the quadrate far forward, 

 and the metapterygoid has accompanied that bone, and lost all 

 connection with the hyomandibular. 



Overlapping the lower portion of the under surface of the 



' Tills series, consisting of 165 sections, was prepared by Giesbrecht's 

 shellac method, the object being first decalcified by a 3 per-cent. solution of 

 IlCl in 96 per cent, alcohol, and then stained in toto with Bismarck brown. 



