1895.] ox SOME CEAKIAL CIL\HACTEBS OF THE SALMOJfOIDS. 299 



Fig. 2. Diagrammatic view of the sensory canal system in the head of Amiurus. 

 (Lettering as above.) 



Pig. 3. Figure showing the series of canal-bones, c.h., in Amiurus, which connect 

 the main canal of the head with the operculo-mandibular branch. 

 From the series of canal-bones, c.6.,the canal passes first into a portion 

 of the hyomandibular, hyom., then into the preoperculum, p.op., and 

 finally into the quadrate, qii. 



Fig. 4. Diagrammatic view of the sensory canal system in the head of Pimelodm. 

 (Lettering as before.) 



Fig. 5. Dendritic branches and grooves from the sub-orbital and operculo- 

 mandibular branch of the main sensory canal of Pimelodus. 



Pig. 6. Lateral view of the head of Callwhthys littoralis, showing the distribution 

 of the sensory canal system. 



Fig. 7. Lateral view of the head of Labeo diissiimieri, showing the distribution of 

 the sense-organs. X 1. (Drawn by Mr. F. W. Crispe.) 



Fig. 8. Longitudinal section through one of the flask-shaped sense-organs in 

 Labeo dussumieri, showing the pore, p., and the sensory filaments, s.fl., 

 arising from the walls of the cavity. The nerve innervating the sense- 

 organ is shown at the base, n.f. 



Fig. 9. Sensory filament, highly magnified ; the nerve fibre, n.f., passes up the 

 filament for nearly two-thirds of its length and then divides into 

 a number of very fine branches, which terminate around the disc, d. 



Fig. 10. Diagrammatic view of the sensory canal system in the head of Eso.v and 

 distribution of the trigeminal and facial nerves. 



Fig. 11. Lateral diagrammatic view of the same. 



Fig. 12. Diagram illustrating the distribution of the mandibular branches of 

 the trigeminal and facial nerves in Esox. 



Fig. 13. Lateral diagrammatic view of the sensory canal system in Balmo. 



Fig. 14. Dorsal view of the same. The sensory canals are coloured yellow. 

 Those canals which are no longer functional and pass through the 

 cranial elements are indicated by a double black line. 



Fig. 15. Canal-bones from the main canal of the head of Salmo. 



Fig. 16. Dorsal diagrammatic view of the sensory canal system of Conger and 

 innervation of the same. The figures 1 to 6 indicate the saccular 

 dilatations, r.op., Eamus opercularis. Other lettering as above. 



Fig. 17. Lateral diagrammatic view of the same. 



Figs. 18, 19. Cartilages from the occipital commissure of the sensory canal 

 system of Conger, 



2. Remarks on some Cranial Characters of the Salmonoids. 

 By G. A. BouLENGER, F.R.S. 



[Eeceived March 27, 1895.] 



Various attempts have been made to split up the Salmonoids 

 into families and subfamilies. In his classification of 1871 \ 

 Prof. Cope proposed to separate the Coregonidae from the 

 Salmonidae owing to their having the parietal bones united in 

 front of the supraoccipital, whUst they are separated by the latter 

 bone in the Salmonidae proper. In a recent paper, Dr. T. GiU * 

 controverts Cope's statement, remarking that " on examination of 

 a skull of Coregonus " he finds the same relation of the bones as in 

 Salmo, whilst the arrangement ascribed to Coregonus is character- 



' Trans. Amer. Philos. Soc. (2) xiv, 1871, p. 454. 

 2 Proc. U.S. Jfat. Mus. xvi. 1894, p. 117. 



