ON THE RELATIONSHIP OF THE FISHES OF 

 THE FAMILY SIGANID.E. 



EDWIN CHAPIN STARKS. 

 Stanford University, California. 



The relationship of the family Siganidse has long been uncer- 

 tain, though modern authors are unanimous in placing it near 

 the family Acanthuridae, which it resembles in form of body and 

 in other external features. It was with the hope of finding some 

 skeletal characters that might further indicate its relationship that 

 this investigation was undertaken. The form chosen to represent 

 its family was Siganus fuscescens from Japan. 



Descriptive. \ . 



The cranium does not depart very much in shape, nor with 

 few exceptions the elements composing it very much in shape, 

 size, or arrangement, from the percoid cranium with the superior 

 ridges little developed as in the genus Perca. The myodome is 

 well developed and opens widely to the exterior at the posterior 

 end of the parasphenoid. The basisphenoid is absent, but at the 

 front of the myodome in the usual place of the descending process 

 from the basisphenoid the interorbital tissue is thickened and 

 separates the eye muscles exactly as the basisphenoid process 

 usually does. The alisphenoids are remote from each other. 

 The exoccipitals meet on the superior surface of the basioccipital ; 

 the vagus foramen in the exoccipital is very large. The crest of 

 the superoccipital is moderately developed, but does not reach 

 to the anterior end of that bone. The frontals are large spongy 

 bones, evenly convex transversely, and without ridges or canals. 

 Posteriorly they reach to the epiotics at each side of the supra- 

 occipital which is wedged in between them. To their anterior 

 ends are attached the wide thin nasals, which are joined to each 

 other at the median line and appear like a continuation of the 

 frontals, arching widely over the nasal chambers forming a 

 rounded roof open only outward and downward. The ethmoid 

 is ossified some distance in front of the prefrontals, and is inter- 



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