MUSTKMTS Li^>VlS. 217 



dorso-median stom is said to aviso mainly from a special 

 centre of grey sul)stance, wliicli Goronowitsch says (pp. 25-27) 

 is peculiar to teleosts, and which he considers as the homo- 

 loguo of the lobus trigemini of Acipenser. Certain fibres 

 found in the dorsal root of Trigeminus II of Acipenser, which 

 root arises from the lobus trigemini of the fish, are, however, 

 said by Goronowitsch not to bo found in the dorso-median 

 stem of Lota. What they are is not evident. The ventro- 

 lateral stem of Tjota is said to be formed largely of motor 

 fibres, but partly of fi])res derived from the same centre as 

 the dorso-median stem. The motor fibres here referred to 

 are, as in Acipenser, unquestionably lateral sensory ones, as 

 Herrick has already pointed out (32, p. 210), and it might be 

 assumed that the dorso-median stem was composed of com- 

 munis fibres, because of Goronowitsch's conclusion that the 

 centre from which the stem arises is the homologue of the 

 h)bus trigoiiiiiii of Acipenser. '^I'lie composition of the two 

 ophthalmic nerves of tlie fish are, however, decidedly opposed 

 to this jiKsumptiou. The dorso-median stem of Trigeminus IT, 

 as I understand (Jorouowitscli, alone sends fibres to his ramus 

 ophthalmicus superficial is, and as that nerve is largely a 

 lateral sensory one, the fil)res it receives through this stem 

 must be lateral sensory ones, if there be no error here. 'J^he 

 nerve is not exclusively a lateral sensory one, since it is said 

 to send certain braiiches to the skin, but this is not important 

 in this connection. The ramus ophthalmicus profundus of 

 Goronowitsch's descriptions, which is simply a deeper strand 

 of the superficialis nerve, is said to be formed of two bundles 

 of fibres, one derived from 'J^rigeminus I, and the other from 

 tho so-calhul dorsal root of the facialis. The former bundle 

 is the spinal fifth component of the ophthalmic nerve, the 

 latter being the connnunis component. The communis com- 

 ponent of the o})litliahin'c nerve thus being accounted for, the 

 special centre of grey substance from which the dorso-median 

 stem of Goronowitsch has its origin, cannot be the homologue 

 of the lobus trigemini of Acipenser if, as I conclude, that 

 lobus is a centre of communis fibres. As the so-called pro- 



