THE NASAL ORGANS OF PIPA AMERICANA.i 



BY IRVING REED BANCROFT. 



The investigations recorded in the following paper were 

 undertaken at the suggestion of Professor Kingsley, who 

 pointed out to me that the nasal structures of the Surinam 

 toad differed considerably from those described by Seydel 

 as occurring in other Batrachia ; and that aside from a short 

 reference by Stewart Lee, no account of the olfactory 

 organ of Pipa americana was accessible. 



The whole work was done by means of sections and 

 plastic models, the slides being the same as those which 

 formed the basis of Arnold's paper on the cranial nerves. 

 The animals were from 9 to 12 mm. in body length and 

 in their general features were much like the adult. The 

 systematic position of Pipa as a member of the Aglossate 

 group of the Anura renders all facts regarding its struct- 

 ure especially interesting. 



For convenience of comparison in my description, I 

 have followed Seydel ('95) in beginning my account at 

 the choana or posterior nasal aperture. The choana opens 

 from the back and upper part of the oral cavity as in 

 other amphibians. It almost immediately shows clearly 

 two main divisions, fig. 9, plate IV. Of these the supe- 

 rior or cavum nasale, c, figs. 2-9, has an ovoid section with 

 the narrow end directed outward. The second division, the 



' Contribution.s from tlie Biological Laboratories of Tufts College, under the 

 direction of J. S. Kingsley, No. xvii. 



ESSKX INST. BULLETIN, VOL KXVII 11 (101) 



