OSTEOLOGY OF RHAMPHOCOTTUS 475 



III. DISCUSSION AND CONCLUSION ' 



From the foregoing it is evident that the families Cottidae and 

 Rhamphocottidae are very closely related so far as osteological 

 characters are concerned. This fact is emphasized by categorical 

 comparison of the two forms. The differences, however, appear 

 to be of sufficient value to elevate Rhamphocottus to the rank of 

 a separate family, although opinion in this regard may differ, 

 as there is wanting, unfortunately, a universal standardization 

 of taxonomic values assigned to given morphological characters 

 by different authors. Not infrequently the differences are only 

 differences of degree, and this appears to be the situation in the 

 case of Rhamphocottus. Nearly all of the characters assigned 

 to distinguish the Rhamphocottidae may be found represented 

 in a greater or lesser degree in some member of the Cottidae. 

 The length of the body, for example, is subject to great variation 

 in the Cottidae. It may be short (Enophrys bison, Ceratocottus 

 dicerans) or greatly elongated, as in Triglops and, Radulinus. 

 The body of Histiocottus bilobus is short, deep, and compressed, 

 the interorbital space is concave, and occipital ridges are devel- 

 oped. In no case, however, are these characters so exaggerated 

 or so prominent as they are in Rhamphocottus. 



In Rhamphocottus there is no slit behind the last gill, but 

 this can hardly be regarded as a family character in this instance, 

 for a similar condition is found in a number of the Cottidae. The 

 condition of the gill membranes is also too variable to be of any 

 special significance. 



The number of vertebrae is slightly less in Rhamphocottus 

 than in the Cottidae. The vertebrae were counted in seven 

 skeletons, and in each the number was twenty-seven, counting 

 the hypural. Jordan and Evermann give the number as twenty- 

 four in Rhamphocottus and thirty to fifty in the Cottidae. 



The myodome is present in both families (Jordan and Evermann 

 state the contrary for Rhamphocottus), and the number of py- 

 loric caeca in Rhamphocottus (five) falls within the limits found 

 in the Cottidae. 



The osteological characters of Rhamphocottus which stand 

 out most prominently are the great length of the snout, the 



