890 



ON COLOUE-VAKiATlON IN FLAt^nSHES. [Dec. 17, 



Eamus ophthalmicus pro- 

 fundus. — Trigeminal. 



Eamus ophthalmicus su- 

 perficialis. — Trigeminal. 



Abducent nerve. 



Facial nerve. 



Eamus hyoideus. — Facial. 



Eamus mandibularis. — 

 Facial. 



Eamus palatinus. — 

 Facial. 



Auditory nerve. 



Glossopharyngeal nerve. 



Vagus. 



Branchial nerve. 



Eamus intestinalis. 



Eamus lateralis super- 

 ficialis inferior. 



Motor branches from 

 Vagus ganglion. 



Eamus vagi lateralis. 



Fig. 1. Lateral view of the head of Chimcsra, showing the distribution of the 

 sensory and ampuUary canal-system. 



2. Portion of the canal-system showing variation. The branch x arising 



from the main canal of the head. 



3. Anterior view of the head of Chimmra, showing the connection of the 



supra- and sub-orbital branches, and the Y'S^iaped commissure 

 connecting the same with the maxillo-mandibular branch. 



4. Diagrammatic view of the dorsal surface of the head of ChimcBra, 



showing the main canal and branches, and the occipital commissure. 



5. Transverse section through the lateral canal, c. Cavity, w./. Nerve- 



fibre. 



6. Cartilaginous hoops from the sub-orbital branch of the main sensory 



canal. 



7. Diagrammatic view of the distribution of the cranial nerves. 



8. Lateral view of the posterior jjortion of the cranium of Chimcera, 



showing the foramina for the exit of the cranial nerves. 



9. Ampullary canals from the head of CJiimcBra : — a, from the occipital 



group ; b, from the sub-orbital group ; c, from the maxillary group. 

 amp. Ampidla. c. Canal, n.f. Nerve-fibre, p. Pore. 



10. Sensory organ from the base of an ampullary canal in Chimmra. 



11. The same from an ampullary canal in Scyllium. cp. Cupola. 



ep. Epithelium. n,f. Nerve-fibre. 



3. Note in Correction of a Paper on Colour-variation in 

 Flat-fishes. By W. Bateson, M.A., F.R.S., Fellow of 

 St. John^s College, Cambridge. 



[Eeceived December 11, 1895.] 



In the ' Proceedings ' of this Society, 1894, p. 246, 1 published an 

 account of an abnormal Brill {Rhombus Icevis) having a series of 

 dark spots along the dorsal and ventral borders of the body on the 

 " blind " side. In commenting on this case, stress was laid on the 

 fact that the corresponding parts of the dorsal and ventral borders 

 had thus varied similarly and simultaneously. At the time I was 



