392 DR. W. O. AYRES ON THE SEBASTOID FISHES [NoV. 10, 



at the best, and disappears so gradually from one species to another, 

 as to be of very little value. It is greatest in S. paucispinis and S. 

 elongatus, and becomes less through S. ovalis, S.Jlavidus, S. mela- 

 nops, S. rosaceus, and S. helvomaculatus ; in S. ruber and S. auri- 

 culatus the fin is about even, and in S. nebulosus and S. nigrocinctus 

 it is slightly rounded. The " protuberant lower jaw" and its " sym- 

 physial swelling beneath" are of greater value as generic features; 

 they are common to five of our species. These five have the lower 

 jaw (which is knobbed at its extremity) continuing nearly the line 

 of extension of the top of the head ; in these five the top of the 

 head is smooth and unarmed. In the remaining six species the two 

 jaws are but little unequal, and the lower is blunt and does not con- 

 tinue the line of extension of the top of the head ; in these six the 

 top of the head is strongly ridged and spinous. But when we look 

 at the species of other waters, we find that the relative development 

 of the jaws can scarcely hold such rank as our groups here would 

 seem to indicate. Sebastes viviparus, for instance, with the surface 

 of the head very rough and spinous, has the knobbed projection of 

 the lower jaw strikingly developed. The " minute scales " belong 

 only to S. paucispinis. It does not seem possible, therefore, that 

 Sebastodes can be retained with such limits as were assigned to it 

 by Mr. Gill. 



Let us now turn to his definition of Sebastichthys. He assigns 

 as its characters "eleven to twelve (XI. + 1. — XII. + 1.) spines in 

 the first dorsal fin, palatine teeth, and the physiognomy of Sebastes 

 (norvefficus)." But all of our species, S. paucispinis included, have 

 the same number of spines in the first dorsal fin — thirteen, or, if a 

 division is preferred, XII. + 1.; and all are furnished with teeth 

 on the palatines. Neither can the " physiognomy" be deemed of 

 value, inasmuch as forms so very unlike are here gathered into one 

 group : the rough, blunt-headed 5. nigrocinctus has little kindred in 

 features to the smooth, sharp-nosed 5. melanops. And as S. norvegicus 

 itself is provided with palatine teeth, the only character remaining 

 to separate Sebastichthys is the number of first dorsal spines. This 

 unsupported, does not appear sufficient. 



The divisions of our Californian species, therefore, which have 

 been proposed by Mr. Gill I cannot adopt, though one of his names 

 may be retained with a different limitation. 



Of the two groups which, as before stated, I find to exist in our 

 waters, one has the top of the head rough, the other has it smooth. 

 The former I refer without hesitation to the genus of which the 

 common species of Massachusetts Bay, S. viviparus, is a member ; 

 and, since Cuvier in his original diagnosis separates Sebastes from 

 Scorpcena in consequence of the absence of fleshy filaments on the 

 head, it seems most natural in making a division of his genus that the 

 name Sebastes should be retained for those which, like Scorpcena, 

 have the top of the head rough with ridges ; and I propose thus to 

 restrict it. For the other group (those with the head smooth) a 

 distinct generic name is needed ; and since the appellation Sebastodes 

 has been proposed for one of the well-marked species, it seems better 



