28 ALLEN 



SECTION I. INTRODUCTORY. 



I. INTRODUCTION. 



The blood-vascular system of fishes is no new subject. It 

 has been carefully worked out for many groups. We have the 

 memoirs of Miiller on Myxine, T. J. Parker on Afustehis, 

 Hyrtl on the roaches, McKenzie on A??ietur?is, Vogt on 

 Sahno, Emery on F^ierasfej', Cuvier and Valenciennes on 

 Pei'ca, and the general account found in Stannius' Anatom}-. 

 The object of this paper is to give a fairly complete account of 

 the vascular system of Ophiodon elongattis (blue cod) ; and to 

 make some comparisons with other members of the suborder 

 LORICATI, the mailed-cheeked fishes. In a later paper I 

 hope to go more into detail with the peripheral endings of the 

 vessels in the organs of the viscera and those of special sense, 

 as well as to take up the lymphatics. 



This group of fishes is distinguished by the extension of the 

 third suborbital bone across the cheek as a sta}' to or toward 

 the preopercle. In view of the wide variation in this group, 

 Dr. Gill says (45)' that it is not a natural division. He, how- 

 ever, divides this suborder into 8 different families, placing the 

 Scorpgenidae (the rock fishes), as the most generalized, on 

 account of their resemblance in form to the Serranidte and 

 SparidcC ; and the Cottidas (the sculpins) are placed as the most 

 specialized. Between these extremes come the family Hexa- 

 grammidae, placed nearer the Scorpjenidae than the Cottidae. 

 There are, however, many points of resemblance to the Cottidce 

 to be found in their osteology, visceral organs, nervous and 

 vascular systems. 



The subfamilies Ucxagravwiince , Ophi'odontincr, Zaniolcpi- 

 dince, and OxylcbiincB, given by Jordan and Evermann (45, p. 

 1864), are very strongly marked. Ofhiodon and probably 

 Zamolcpis are about as closely related to Scorpccnichthys^ a 

 sculpin, as they are to Hcxagrammos^ and should be regarded 

 as types of distinct families. 



The following species of fishes were studied. 



' All figures in brackets refer to bibliography at the end of the paper. 



