208 ME. W. P, PTCKAFT ON THE 



without forming a false passage, a bristle about tbe size of an 



ordinary horse-hair " 



The external nostril in every species of adult Cormorant which 

 I have examined appears to lie vrithout and below the rhino- 

 thecal groove (fig. 1, «.«.), and not at its end as just described. 

 As seen in the figure, it is represented by a shallow groove 



Fig. 2. 



Left side Tiew of the head of an embryo Corm orant to show the relatively large 

 narial aperture lying within the rhinothecal gi-ooye. — rh.g., rhinothecal 

 groove. 



pointing downwards and forwards to the tomium. Its upper end 

 joins the rhinothecal groove at its base, where it passes into the 

 naked skin, of the lores. 



I have not been able to find any trace of this narial groove, or 

 aperture, in the Gannets. 



I failed entirely to pass even the finest bristle up this groove 

 into the nasal cavity, though I tried in many species of Cormorant — 

 one a fresh, and the rest spirit-specimens. 



My next step in this investigation was to force the rhampho- 

 theca from the jaw. The rhinotheca was first raised and then 

 the gnathotheca. This last brought away with it a short rod-like 

 plug (fig. 1, p. 207) — apparently an inward and backward con- 

 tinuation of that part of the rhamphotheca surrounding the 

 external narial aperture, indicated by the groove just described 

 (fig. 1, n.a.). Thus, instead of surrounding the aperture and 

 giving place in this region to mucous membrane, the sheath 

 seems to have grown inwards so as to form a horny tubular 



