44 BULLETIN 150, UNITED STATES NATIONAL MUSEUM 



forecasts the closing of the opaning. The posterior nostril opens 

 above the anterior part of the eye. The tube never projects as high 

 above the surface of the head as the anterior nostril tube. In a few 

 species, as in Liparis owstoni, the rim of the tube is distinctly raised 

 above the surface of the head. In Liparis rutteri, callyodon, dennyi, 

 and several other species the rim anteriorly is raised into a fingerlike 

 projection. The anterior nostril tube always projects above the 

 surface of the head. The length of the tube varies somewhat, but 

 it is doubtful if this variation can be utilized to any extent in separating 

 species. Some specimens of Liparis rutteri and major have a very 

 short tube, there being a variation within the species. In Liparis 

 tessellatus the anterior tube projects hardly more than the posterior 

 tube in some of the other species. 



Eye. — The proportionate size of the eye varies considerably 

 throughout the genus and is of value in distinguishing species. As 

 the size of the eyes varies with age too much stress must not be placed 

 upon a difference in the sizes of the eyes of two specimens unless these 

 are of the same length. The eye varies in the different species from 

 4 to 10.5 in the length of the head. In some species, such as Liparis 

 megacephalus and agassizii, the lower half of the eye is silvery. The 

 sUvery pigment frequently disappears in preserved specimens. 



Pores. — The pore formula for the genus is 2 on the snout, 6 in the 

 maxillary series, 7 in the mandibular series, and 2 above the gill slit. 

 These numbers are constant for all the specimens examined by the 

 writer. The position of the snout pores in relation to the anterior 

 nostril, the maxillary pores in relation to the eye, and the supra- 

 branchial pores in relation to the gill slit and to each other varies, 

 but these variations appear to be of little practical value in separating 

 closely related species. 



In many of the species rudimentary pores can be seen in the region 

 of the lateral line and scattered in the region of the gill slit and nape. 

 These are always closed, the lips can sometimes be seen at the tips 

 of small papillae. The papillae are always white and frequently 

 surrounded by a dark ring. When the skin is transparent and lax 

 it is difficult to detect these pores. They have not been demon- 

 strated in all the species. Their taxonomic importance has yet to 

 be investigated. 



Teeth. — All the species of Liparis have trilobed teeth. In Liparis 

 major and ingens the inner teeth are simple or weakly trilobed. The 

 teeth are arranged in oblique rows and form broad bands. There 

 are usually more oblique rows in the upper jaw. The oblique rows 

 are usually distinct though in some of the giant species they become 

 irregular and obscure. In some of the species the number of oblique 

 rows appears to be the same in the young and adults and in other 

 species different. 



