﻿THE OSSEOUS SYSTEM OF OPHIOCEPHALUS STRIATUS 



BLOCH 



By Artemas L. Day 



(From the Department of Zoology, College of Liberal Arts, 

 University of the Philippines) 



Nineteen plates and 7 text figures 



In working out the internal skeleton of Ophiocephalus striatus 

 Bloch, several specimens were dissected, although for the most 

 part bones of a single individual have been used for purposes of 

 illustrating the disarticulated bones. The bones of the skeleton 

 of the fish represented in Plate I have been illustrated in this 

 plate only, with the exception of a certain few, as for example 

 anterior dorsal radials (85,115) shown in text fig. 2, the dorsal 

 ray and internal spine, and the anal ray and interhaemal spine 

 shown in text fig. 5. 



In a few other instances bones of other individuals have 

 been used; as, for instance, the glossohyal (65) shown in text 

 fig. 7, the top of the skull, disarticulated, and a part of the 

 suspensorium at the top of Plate VII. 



The fish from the skeleton of which the illustrations of the 

 disarticulated bones were made, with the exception of the few 

 just named, was 50 centimeters long. Several smaller fish 

 were also dissected, and the number of bones was found to vary 

 considerably in specimens of different sizes. In several large 

 individuals the total number of ribs varied from 41 to 45, the 

 double ribs from 12 to 15, the vertebrae from 50 to 51, the 

 interneural spines from 40 to 42, and the interhaemal spines 

 from 23 to 25. 



The character of certain bones in the larger specimen is very 

 different from that of the bones of smaller fish. In small 

 specimens the supraethmoid (75) and the glossohyal (65) are 

 cartilaginous, and even in the largest specimen dissected the 

 latter was found to be somewhat ossified in the central portion 

 only. The partially ossified region is indicated in text fig. 7. 

 With few exceptions the nomenclature of Starks ' is here 

 followed. 



1 Proc. Wash. Acad. Sci. (1901), 3, 507. 



19 



