REVISION OF THE FISH FAMILY LIPARIDAE 17 



a perceptible change in the position of the origin of the dorsal. The 

 shape of the body is somewhat modified in Careprodus and Parali- 

 paris, but this would hardly obliterate any change that might occur 

 in the origin of the dorsal. The origin of the dorsal in Careprodus 

 and Paraliparis is not perceptibly farther back than in Liparis. 

 This indicates that in these genera the spinous dorsal has not been 

 lost. 



The proportional number of dorsal and anal rays also favors the 

 view that the spines have not been lost in Careprodus and Para- 

 liparis. In Liparis the number of dorsal rays (counting the spines) 

 varies from four to nine more than the number of anal rays. Of these 

 the anterior 4 to 7 or 8 are undivided or spinous. If these spines 

 have been lost in Careprodus and Paraliparis the number of dorsal 

 and anal rays should be about equal. But we do not find this to be 

 true. In Careprodus the number of dorsal rays varies from 4 to 9 

 more than the number of anal rays. In Paraliparis the dorsal has 

 from 3 to 10 more rays than the anal. The spinous dorsal appar- 

 ently has not been lost in these genera. If the spinous dorsal has 

 not been lost in these genera it possibly has not been lost in the other 

 genera in which the notch is absent and the anterior t&js divided. 



From these general considerations we are led to believe that in the 

 Liparidae the dorsal notch bears the same relation to the spines and 

 soft rays as in the Cyclopteridae, that the rays in front of the notch, or 

 the undivided rays, are homologous to ancestral spines and that the 

 unsegmented rays behind the notch and the unsegmented anal rays 

 can not be so homologized, but represent soft rays which have lost 

 the segmented condition. The evidence concerning the fate of the 

 spines in those species in which the notch is absent and the anterior 

 rays divided seems to indicate that the spines have not been lost but 

 have become divided. Assuming that spines have been formed from 

 rays by the obliteration of the union of the two lateral shafts and the 

 loss of segmentation we have, in these degenerated fishes, in the 

 failure of the two shafts of the anterior dorsal rays to coalesce, an 

 example of a retarded or reverted condition of a structure. 



