REVISION OF THE FISH FAMILY LIPARIDAE 39 



RELATIONSHIPS OF THE GENERA 



UPABIS 



The species of the genus Liparis bear the closest resemblance to 

 the Cyciopteridae, and we may reasonably assume that this genus is 

 the most generaUzed one in the family and the one from which the 

 other genera have directly or indirectly been derived. It is among 

 the tide-pool species of the genus that we find the closest resemblance 

 to the Cyciopteridae. These species have the smallest number of 

 vertebrae and fin rays, the shortest connection between the dorsals, 

 caudal, and anal fin, and the dorsal notched. L. callyodon is a good 

 example of this type of species. The characteristics which this species 

 has in common with some or all the other species of the genus and 

 which point to this genus as being the most primitive are the small 

 number of vertebrae, the dorsal notch, the short connection between 

 the vertical fins, the trilobed teeth, the variegated coloration, and the 

 two nostrils. 



It is, of course, possible that the most primitive species is best 

 represented by some of the deeper-water species such as L. megace- 

 phalus. This species has a very wide gill slit. Prickles, presumably 

 a primitive character, are most common among the deeper-water 

 species. 



It seems more likely that the genus originated in the tide pools and 

 that representatives descended to greater depths, retaining certain 

 primitive characters as the enlarged giU slit and prickles and becoming 

 modified in other ways, such as the increase in the number of vertebrae 

 and the connection between the vertical fins. The species remaining 

 or originating in the tide pools doubtless retained a larger number of 

 primitive characteristics though becoming modified in some ways. 

 They may have developed more compact, shorter bodies, larger disks, 

 and smaller gill slits and thus became better fitted to withstand the 

 beating of the waves on our rugged coasts. It appears to us that the 

 tide-pool species, such as L. callyodon and L. mwcosws, in their aggregate 

 of characters most nearly resemble the ancestors of the group and the 

 Cyciopteridae. 



POLTPEKA 



The genus Polypera differs from Liparis solely in the greatly in- 

 creased number of pyloric coeca. All the species of Polypera have more 

 than 200 closely matted pyloric coeca and none of the species of 

 Liparis have 100. The pyloric coeca in Polypera are in a thick mass 

 and can be distinguished at a glance without counting from the 

 larger coeca of the species of Liparis. In the distribution, small gill 

 slit, the notched dorsal, and the short connection between the vertical 

 fins Polypera most closely resembles the tide-pool species of Liparis. 

 In the increased number of fin rays Polypera bears a closer resemblance 

 to the deeper-water species. 



