The Skeleton of the Fish 39 



ossified dermal tissues. Membrane bones are not found in the 

 sharks and lampreys, but are developed in an elaborate coat 

 of mail in some extinct forms. 



Names of Bones of Fishes. In the study of the names of 

 the bones of fishes it will be more convenient to begin with a 

 highly specialized form in which each of the various structures 

 is present and in its normal position. 



To this end we present a series of figures of a typical form, 

 choosing, after Starks, the striped bass (Roccus lineatus) of the 

 Atlantic coast of the United States. For this set of plates, 

 drawn from nature by Mrs. Chloe Lesley Starks, we are indebted 

 to the courtesy of Mr. Edwin Chapin Starks. The figures of the 

 striped bass illustrate a noteworthy paper on "The Synonymy 

 of the Fish Skeleton," published by the Washington Academy 

 of Science in 1901. 



Bones of the Cranium. The vomer (i) is the anterior part 

 of the roof of the mouth, armed with small teeth in the striped 

 bass and in many other fishes, but often toothless. The eth- 

 moid (2) lies behind the vomer on the upper surface of the skull, 

 and the prefrontal (3) projects on either side and behind the 

 ethmoid, the nostrils usually lying over or near it and near the 

 nasal bone (51). Between the eyes above are the two frontal 

 (4) bones joined by a suture. On the side behind the posterior 

 angle of the frontal is the s phenolic (5) above the posterior part 

 of the eye. Behind each frontal is the parietal (6). Behind 

 the parietal and more or less turned inward over the ear-cavity 

 is the epiolic (7). Between the parietals, and in most fishes 

 rising into a thin crest, is the supraoccipital (8), which bounds 

 the cranium above and behind, its posterior margin being 

 usually a vertical knife-like edge. The plerolic (9) forms a sort 

 of wing or free margin behind the epiotic and over the ear- 

 cavity. The opisthotic (10) is a small, hard, irregular bone 

 behind the pterotic. The exoccipital (n) forms a concave joint 

 or condyle on each side of the basioccipital (12), by which the 

 vertebral column is joined to the skull. The parasphenoid (13) 

 forms a narrow ridge of the roof of the mouth, connecting the 

 vomer with the basioccipital. In some fishes of primitive struc- 

 ture (Salmo, Beryx] there is another bone, called orbitosphenoid, 

 on the middle line above and between the eyes. The basis phe- 



