397 



has been published further upon the anatomy of this organ in the 

 AustraHan Mud Fish (Neoceratodus or as it was called at that date 

 Ceratodus). 



In view of the interest that attaches to the Dipneusti from an 

 evolutionary point of view and also from the fact that Eetzius 

 was unable owing to the imperfect preservation of his material to 

 give quite a complete account of the coarse anatomy of the laby- 

 rinth in Ceratodus it is incumbent upon anyone with suitable material 

 at hand to complete so far as possible the description left imperfect 

 by Eetzius. 



Through the kindness of Colonel C. E. Shepherd I have re- 

 cently been able to examine the membranous labyrinths from an 

 exceptionally well-preserved head of Neoceratodus. 



C.P,S. 



Fig. 1. The left labyrinth of Neoceratodus forsteri, mesial aspect. Part of the 

 mesial walls of the utricle and saccule have been removed. C.RS. canalis recessu- 

 saccularis ; C. US. canalis utriculo-saccularis. D. diverticulum of utricular floor ; 

 D.EDL, ductus endolymphaticus- L. Ligament between diverticulum und saccule ; 

 M.N., macula neglecta; R. recessus utriculi; R.Ä. ramus anterior of otic nerve; 

 R.N. ramulus neglectus; R.P. Ramus posterior of otic nerve; R.S. ramulus sacculi 

 of R.A.., S. sacculus; S. E.D.L. saccus endolymphaticus; Y. vein? 



I find that in almost all particulars they agree with the description 

 and figures (1. c. p. 144, PL 24, fig. 1—8) given by Eetzius so far as 



