gill] the umbras 305 



behind the branchial chamber. The head has a bridle-hke band ex- 

 tending from the snout on to the opercukmi, skipping the eye. The 

 fins are immaculate. 



There are slight structural differences in proportions of body, 

 head, and fins between the several species, but they are so unim- 

 portant that they need not be specified here. The U. S. National 

 Museum has numerous specimens of all the species. To Dr. Hugh 

 M. Smith, Deputy Commissioner of Fisheries, the writer is also in- 

 debted for the opportunity to observe living individuals of the 

 Eastern Umbra which were obtained by digging or dipping deep into 

 the mud at the bottom of a run near the city of Washington. 



It is really remarkable that, with such adaptability and such power 

 of endurance as they possess, the range of the genus should now be 

 so restricted. Restricted it undoubtedly is, for the European and 

 American species must be the relics of a once widely dispersed group. 



V 

 Here have been given the essentials of what is known respecting 

 the habits and economy of the Umbrids. Several of the statements, 

 however, require verification, especially such as refer to the segre- 

 gation of the males from the females and the ascent of both up- 

 stream. The entire nature of the oviposition, also, should be espe- 

 cially investigated ; and there are the history of the development of 

 the young, the growth from season to season, and the age at which 

 maturity is attained to be inquired into. The present sketch is, 

 therefore, only a preliminary from which to start. 



