574 CALIFORNIA ACADEMY OF SCIENCES. 



There has hitherto been no agreement among ichthy- 

 ologists as to the boundaries of the genera of rose- and 

 rock-fishes. European writers, beheving that the differ- 

 ence in the number of dorsal spines is not a sufficient 

 basis. for a generic separation of the Pacific forms, inglude 

 them all in the old Cuvierian genus Sehastes. American 

 writers, however, lay greater stress on this difference, 

 which they have shown to be connected with a constant 

 difference in the number of vertebrae. They are also 

 prompted by the desirability of breaking up so large and 

 unwieldy a genus into smaller natural groups, and have 

 thus not only segregated the Pacific forms with 13 dorsal 

 spines and 12 -[-15 vertebrae in the genus Sebastodes, but 

 have made several efforts to break up the latter genus 

 into several smaller ones. Between 1854 ^"^ 1861 W. 

 O. Ayres^ described numerous species from the Pacific 

 Coast of California, including them all under the old genus 

 Sebastes. In 1861 GilP proposed the genus Sebastodesiox 

 the Sebastes ^aiixi'spinis of Ayres. In 1862 he placed all 

 the remaining rock-fish of the West Coast in a new genus, 

 Sebastichthys, but all the generic characters which he as- 

 signed have proved worthless. 



Ayres accepted the genus Sebastodes, but redefined it so 

 as to include the species ovalis, jiavidus, mela7iops and -pin- 

 niger. It will be seen that this was a natural group, the 

 characters which he selected being correlated with others 

 of which he knew nothing. He retained all the remain- 

 ing West Coast rock-fish in the genus Sebastes " with the 

 characters of Sebastes as given by Cuvier, except that the 

 top of the head is always marked by spinous ridges, the 

 orbits being commonly crested, so as to leave a depression 

 between them." 



1 Ayres: Proc. Cal. Acad. Sci., 1854-1862. 



2 Gill: Proc. Acad. Nat. Sci. Phil., 1861, p. 165; 1862, p. 329. 



