12 



ART. 2.— BASHFORD DEAN. 



opening. Accordingly in the numerical relations of the gills the 

 present species fills up the gap which has existed between the 

 bdellostomas with a small number of gills, i.e., those of five and six 

 (seven) gill- pairs, and those of many gills, from ten to fifteen. For 

 in addition to the regular number of eight gills in the new species, 

 we must include the ductus œsophagœus as representing on one side 

 at least a ninth gill. Judging by the conditions in other hag-fish, 

 moreover, I have no doubt that variations occur in the present species 

 which would make the foregoing transition still more convincing. I 



A 



B 



Text Fig. 3. Dental cusps of new Japanese myxinoids. 



A. Paramyxine atami. 



B. Homea okinoseana. 



note in this connection that a numerical variation occurs in the gills of 

 H. bargeri. In as large a proportion as ten per cent, of the material 

 examined, I find that the excurrent opening of the sixth left 

 branchial sac opens to the surface in front of the ductus œsophagœus. 

 On PI. I, Fig. 1 is shown, the lateral view of this species. It 

 has been drawn to scale so that the proportion of " head " and 

 " trunk " can be estimated. By comparison of Text-fig. 2 B with 

 Text-figs. 2 A, C, Z), E, it will be seen that the outer, gill openings 



