10 BULLETIN 150, UNITED STATES NATIONAL MUSEUM 



The taxonomic importance of the open pores has not been 

 thoroughly investigated. They offer a promising field for further 

 research and may be found to be of value in working out the genetic 

 relationships of the genera. All of the species of Liparis and most 

 of the species of Careproctus have two suprabranchial pores; a few 

 of the species of Careproctus and all the species of Paraliparis seem 

 to have but a single suprabranchial pore. All the genera derived 

 from Paraliparis have but one suprabranchial pore. In certain 

 species of Careproctus there seems to be a variation of from 2 to 1 

 suprabranchial pore. The pore formula of some species of Paraliparis 

 is 2-5-6-1, as though the upper pore of the last three series had been 

 lost. In certain species of Liparis, as in L. rliodosoma, the lower 

 suprabranchial pore is reduced, but in some species of Careproctus 

 it is the upper pore that has been reduced. 



The position of the pores varies considerably. The suprabranchial 

 pores are in some species separated by a distance greater than the 

 eye, and in others they are very close together. The upper pore 

 on the snout in Liparis is typically some distance in front of the 

 nostril; in Careproctus it is closer to the nostril; in Paraliparis it 

 may be between and in Nectoliparis above the nostrils. This appears 

 to be due to a shifting of both the pores and the nostrils. The 

 anterior snout pore lies either in front of the upper pore or in front 

 and lateral to it. The snout pores and the nostril form the apices 

 of variously shaped triangles. The anterior mandibular pores in 

 certain species of Careproctus and Paraliparis have a common 

 opening. 



Gill slit. — In each of the three large genera, Liparis, Careproctus, 

 and Paraliparis, we find the gill slit undergoing the same amount 

 of variation from a position above the pectoral to one extending 

 down in front of it. There is a difference, however, in the frequence 

 with which the gill slit extends down in front of the pectoral. In 

 Liparis two-thirds of the species have the gill slit enlarged and 

 extending in front of the pectoral. The reduced gill slit is restricted 

 mainly to the tide-pool species, the enlarged slit to the deeper-water 

 and more specialized forms of the genus. About one-third of the 

 species of Careproctus have the gill slit extending in front of the 

 pectoral, and these are found in both the most generalized and 

 specialized members of the genus. The gill slit is widest in the 

 most specialized forms of this genus. An extreme reduction of the 

 gill slit is found in GyriniclitJiys in which it is high above the pectoral 

 and no larger than the diameter of a dissecting needle. In only 

 one species, ISl ectoliparis pelagicus, is the gill slit confined to the 

 front of the pectoral. 



Teeth. — The teeth exhibit a wide range of variation in shape, size 

 of pulp cavity, and arrangement. The teeth may be either trilobed 



