250 



bulletin: museum of co]mparative zoology. 



Explanation of Plates. 



All drawings were made with the aid of the camera lucida. 



The magnification for Plate 1 was obtained with a Leitz dissecting micro- 

 scope; for Plate 2, a Reichert objective No. .3 and ocular No. 4 were used; and 

 for Plates 3, 4, 5, and 6, a Reichert -^^ inch homogeneous immersion objective 

 and ocular No. 4. 



Abbreviations. 



Ampulla anterior. 



Ampulla horizontalis. 



Ampulla posterior. 



Apex sinus superioris. 



Canalis anterior. 



Canalis horizontalis. 



Canalis posterior. 



Crista acustica. 



Lagena. 



Macula acustica lagenae. 



Macula neglecta. 



Macula acustica rec. utriculi. 



Macula acustica sacculi. 



Nervus octavus. 



Recessus utriculi. 



Ramus anterior. 



Ramulus amp. anterioris. 



Ramulus amp. horizontalis. 



Ramulus amp. posterioris. 



Ramulus 1 genae. 



Ramus posterior. 



Sacculus. 



Sinus utriculi superioris. 



Utriculus. 



