054 MR FRANK J. COLE ON THE 



the superficial ophthalmic, but this is bridged over by a thin membrane of nervous tissue. 

 The superficial ophthalmic now enters the cartilage of the cranium, and immediately 

 expands into a large ganglion. Whilst still in the cranium two nerves are given off, 

 supplying the first 3 sense organs of the supra-orbital canal. Having emerged into 

 the orbit, the superficial ophthalmic courses over the eye muscles, and sometimes, as 

 shown in fig. 1, imperfectly separates into two large bundles, but there is always a 

 1 >ridge of nervous matter connecting them. Owing to the pressure of the eye, the super- 

 ficial ophthalmic is considerably flattened out in the orbit, and whilst there gives off five 

 nerves, supplying the next 8 sense organs of the supra-orbital canal. The succeeding 

 two organs are supplied by the profundus. The ophthalmic now enters a somewhat 

 long canal opening anteriorly into the orbit, and whilst in it receives and fuses with the 

 ophthalmicus profundus of the Vth. Immediately on leaving this canal the superficialis 

 breaks up and plunges into the huge superficial ophthalmic group of ampullae. The 

 snout of Chimasra is divided into three longitudinal compartments by means of two 

 vertical fenestrated ligamentous partitions. These partitions join at right angles 

 anteriorly, and then lie at an appreciable distance beneath and parallel to the skin, the 

 nerves to the sensory canals passing through the fenestras. The median and largest 

 compartment is occupied by the two superficial ophthalmic groups of ampullae (see fig. 

 1), whilst the outer compartments lodge the two buccal groups. The compound nature 

 of the ampullae of these groups has been accurately figured and described by Leydig (7). 

 Each superficial ophthalmic group consists of a small dorsal and a much larger ventral 

 portion (see fig. l). On entering the snout, the superficial ophthalmic, as above described, 

 breaks up into numerous bundles. Most of these go to ampullae, but six fine 

 bundles separate out, and passing between the two ophthalmic groups of ampullas, supply 

 the remaining 14 sense organs of the supra-orbital canal. The single median sense 

 organ of the snout was supplied from the left side. Excluding the two profundus 

 organs, there were thus 25 sense organs in the supra-orbital canal of the Chimasra I 

 dissected. 



(2) Buccal. — Arises by a single root from the dorsal surface of the brain, on a level 

 with and immediately behind the dorsal border of the restiform body. It then courses 

 downwards and forwards, applied to the surface of the brain, and passes under the ventral 

 root of the superficial ophthalmic, overlying however the roots of the trigeminus. Just 

 opposite the ventral border of the restiform bodies it gives off the dorsal root of the 

 superficial ophthalmic, and before entering the cranium does the same to the hyoman- 

 dibular trunk. Unless ventral fibres enter into the composition of the buccal by means 

 of these two anastomoses, the buccal consists of dorsal fibres only. Whilst in the 

 cranium the buccal overlies and obscures the root of the trigeminus, but remains quite 

 separate from it, and expands to form the large buccal ganglion. On entering the orbit, 

 the buccal is seen to lie partly over and partly behind the trigeminus (see figs. 1 and 3), 

 and almost immediately gives off from its ventral border the ramus oticus, which 



