Tubercles on body of unequal size; their distribution and character corroborate 

 this variation. Usually there are four main rows of tubercles between which are 

 the smaller. All tubercles possess spines, but fewer than in E. birulai . In an 

 Anadyr Gulf example there are 5-7 suggested raws in the precarbital distance, some 

 tubercles small and in no order. Between the first and second dorsal are one or 

 two very different tubercles . 



■ f^ G -^ 





(t-"!^. 





Fig. 7 Eumicrotremus orbis (Gunther) 

 juv. from between St. Lawrence 

 Id. and Cape Chaplin 



Fig. 8 Eumicrotremus birulai Popov 

 juv. near Natalie Gulf 



(The number is not fixed at two as stated by A. M. Popov (1928, pp. 10, 11)). One 

 example from this locality had only one (from two fuzed) tubercle. Chin covered 

 by small low tubercles and have well developed papillae . First dorsal low with 

 distinct rays which are covered by low and randomly distributed tubercles, of 

 spine like shape. Anus placed at posterior end of disk not more than at a 

 single eye diameter's distance. i/ Length of nasal tube varies widely and cannot 

 be employed as a systematic character. In our collection there are both extremes. 



The one year old examples (35 mm) have the tubercles of the main rows 

 developed but with only a few spines (fig. 7). 



This species is closest to E . spinosus (Muller) from the North Atlantic. 

 It is absent in polar seas. The distribution of these species is amphi -boreal 

 to each other. 



1/ 



In the material from anadyr Gulf and from Koriak Land are numerous examples 

 that deviate toward E. birulai. Possibly the two species are found in this 

 region and hybridize with the main characteristics of E. orbis being dominant. 

 However, the possibility that a detailed study will show these forms to be a 

 particular form of E. orbis is not to be excluded. 



38 



