48 BULLETIN 150, UNITED STATES NATIONAL MUSEUM 



Liparis pulchellus, tessellatus, and steineni has an equal or smaller 

 number of rays than the anal. Liparis major has a smaller number of 

 pectoral than anal rays and in this character, as well as the simple 

 teeth, reduced posterior nostril, and black peritoneum, approaches 

 the condition found in Careproctus. 



The majority of the species have the pectoral notched. This is 

 caused by the rays near the middle of the fin being shorter than some 

 of those below. In Liparis owstoni, tanakae, and possibly aniarctica 

 and steineni these rays are not shorter than those below and the mar- 

 gin of the fin is not notched. Whether or not this is true of the 

 pectoral in the young is unknown. There is some evidence that the 

 young of Liparis tanakae have a Ughtly notched pectoral. 



In Liparis the lower pectoral lobe is never elongate. The length 

 varies among the species and with age. In some species it does not 

 extend beyond the disk and in others reaches nearly to the anal. The 

 variation in length of either the upper or lower lobe between related 

 species is so slight as to be of little taxonomic value. In all the 

 species the rays of the lower lobe are somewhat thickened, partly free, 

 and graduated in length. 



The upper edge of the pectoral fin is at about the same level on the 

 body in all the species. 



Dislc. — The size of the disk is one of the important specific char- 

 acters. The diameter of the disk is contained from 1 .5 to 3.2 times in 

 the head. The proportional size of the disk varies with age, being 

 larger in the young individuals. 



The distance from the tip of the lower jaw to the disk varies with the 

 length of the head and the size and position of the disk. It may be 

 greater or less than the diameter of the disk. The number of times it 

 is contained in the head varies with the species and, in a few cases, 

 serves to distinguish them. 



The width of the flap varies slightly, but not enough to be of specific 

 value. It may be greater or less than the diameter of the center of the 

 disk. The disk is round or shghtly oval, but never triangular as in 

 some species of Careproctus. The long diameter of the disk is usually 

 parallel with the body. The margin of the disk is indented at the 

 sides anteriorly. 



Vent. — The position of the vent varies but little among the differ- 

 ent species. It is close to the disk, but usually about midway between 

 disk and the origin of the anal fin. The distance between disk and 

 vent varies from 1 .6 to 4.8 in the head. The amount of variation with- 

 in a species may be due to age. 



Pseudohrancliiae. — The writer investigated the pseudobranchiae 

 solely for the purpose of demonstrating their presence in the species. 

 It was noted however that there vv^ere usually about five filaments. 

 Pseudobranchiae were seen on the following species : gihhus, cyclopus, 

 agossizii, fucensis, tunicatus, lierschelinus, tanakae, and pulchellus. 



