98 BULLETIN 150, UNITED STATES NATIONAL MUSEUM 



species. In these species the cutting surfaces of the bands of teeth 

 appear horizontal when the jaws are opened. This is because the 

 anterior teeth are not so much smaller than the inner teeth and not 

 placed so low on the jaw bones as among other species. Also the 

 inner teeth are recurved which helps to flatten the cutting surfaces 

 of the bands of teeth. 



The characters of the teeth are of little or no practical use in separat- 

 ing closely related species but are of considerable value in indicating 

 the general relationships of the species. 



Dorsal jin. — The rays of the dorsal fin are difficult to count on 

 account of the delicate nature of these fishes. The rays appear as 

 delicate threads in the fin tissue. The writer found the most satis- 

 factory method for counting the fin rays to be to place the specimen 

 on a piece of glass or the dissecting microscope, slit the fin membrane 

 at the margin of the fin and fold it back on the body, and, with a 

 pair of hooked needles, separate the rays as they are counted. It is 

 sometimes an advantage with very delicate specimens to place them 

 in a glass vessel, cover with alcohol, and examine under the simple 

 microscope, the light being properly controlled from below. 



The number of dorsal rays ranges from about 40 to 60. On account 

 of the difficulty of making accurate counts of the number of dorsal or 

 anal rays it has not been considered advisable to depend upon the 

 number of these rays to separate species. With the study of more 

 material (many of the species are represented by a single specimen), 

 it will be possible to determine the number and amount of variation 

 of the dorsal and anal fin rays. Then it will probably be found that 

 the number of rays will serve as an index to many of the species. 



The origin of the dorsal varies slightly but can not be used to advan- 

 tage in distinguishing species at the present time. The length of the 

 first dorsal ray, as compared with the diameter of the eye, serves to 

 separate some of the species. This is a character which deserves 

 further investigation. In C. yycnosoma the anterior dorsal rays are 

 rather stiff and project distinctly. This condition is characteristic 

 of the species of Liparis. In many of the species the anterior dorsal 

 rays are buried in pseudotissue and do not come in contact with the 

 fin membrane. They can be seen only by dissecting the fin. In 

 such fins the anterior rays extend undulatingly backward. 



The dorsal notch is absent or but faintly indicated in this genus. 

 Two species, C. attenuaius and C. pycnosoma, appear to have the dorsal 

 notch persisting. In the specimens known the fourth, fifth, and 

 sixth rays appear slightly shorter than the preceding one. 



The anterior rays are unsegmented but appear to be divided longi- 

 tudinally and thus differ from the condition of the anterior rays in the 

 species of Liparis. The following table indicates the species in which 



