CHONDROCRANIUM OF SYNGNATHUS FUSCUS 439 



independently in any teleost, but must at least have a fibrous, 

 if not a cartilaginous connection with the more posteriorly 

 situated pterygoquadrate. Such a condition exists at this stage 

 in Syngnathus, and whatever the later conditions may be, this 

 fibrous connection is primary. In this respect the relations of 

 the posterior end of the palatine cartilage resemble that of the 

 10-mm. Amiurus (Kindred) in which the posterior end of the 

 palatine is connected with the anterior end of the pterygo- 

 quadrate by a connective-tissue bridge. 



McMurrich in his description of Syngnathus peckianus failed 

 to recognize this relationship and stated that the 'ethmopalatine' 

 was independent of the pterygoquadrate. The anterior relation 

 of the palatine cartilage to the ethmoid plate is similar to that 

 of Gasterosteus — a condition which Swinnerton calls acrartete. 

 If it is assumed that the fibrous connection is the homologue of 

 the intervening cartilage in Salmo, then the fibrous connection 

 between the posterior end of the palatine and the anterior end 

 of the pterygoquadrate which passes ventral to the ectethmoid 

 cartilage in Syngnathus may represent a condition comparable 

 to that in Salmo, where the posterior part of the palatine process 

 of the palatoquadrate articulates with the ventral surface of 

 the ectethmoid process. 



In the 8-mm. Syngnathus, the mandible is formed by the fused 

 meckelian cartilages. They project for a short distance beyond 

 the anterior margin of the dorsal part of the oral gape and form 

 the axes of the shovel-like ventral portion (figs. 1, 2). The 

 anterior end of each meckelian cartilage abuts against its fellow 

 in the median line by a flat thickened surface. The cartilage 

 cells on the abutting surfaces are very small, numerous, and 

 arranged in a vertical row, separated from each other by the 

 fused perichondria. Posteriorly, the cartilages diverge, become 

 smaller in cross-section, and are connected with each other 

 mesially for a short distance by a slender band of developing 

 muscle tissue. The muscle tissue is replaced more posteriorly 

 by embryonal connective tissue. Each meckelian cartilage is 

 gradually compressed to form the coronoid process (fig. 1). A 

 small notch on the anteroventral face of this region separates 



