1 76 STRONG. [Vol. X. 



lets sometimes apparently distinct and sometimes fused with 

 the sensory portion, to Stannius's first root, to Gegenbaur's 

 V a, and to Jackson and Clarke's V a. Their first dorsal root 

 {a) of the VII is the one derived from the lobus trigemini in 

 all probability, and is correctly homologized. Their second ven- 

 tral root [b) of the VII must be regarded as compound, consist- 

 ing of a lateral line portion, a motor, and possibly a root from 

 the lobus vagi. Compare tadpole (see below) and Gorono- 

 witsch's account of Acipenser. 



Ewart (18) has described these roots in Laemargns as fol- 

 lows : the ophthalmicus profundus arises by a separate root in 

 front of the main Trigeminus. The latter arises by a large 

 root on a line with the ventral roots of the Facialis complex. 

 Its branches are the ophthalmicus superficialis, maxillaris, and 

 mandibularis. The Facialis includes four separate nerves: 

 (i) Ophthalmicus superficialis, arising from the so-called tri- 

 geminal nucleus by a root dorsad and caudad of all the others. 

 It communicates with the buccalis as it passes through the 

 cranial walls at a higher level than the Trigeminus and oph- 

 thalmicus profundus. (2) Buccalis arises behind and at a slightly 

 higher level than the trigeminal. It is infraorbital. (3) Pala- 

 tinus and hyomandibularis arise by a large root between the 

 Trigeminus and Auditory, and partly under cover of the bucca- 

 lis. It receives fibres from (i), and then passes outwards with 

 the Auditory, giving off the R. palatinus, and finally dividing 

 into branches to muscles and to canals and ampullae not sup- 

 plied by (i), nor (2), nor the R. lateralis. 



Here (2) and part of (3) are lateral-line roots. (3) must be 

 regarded as in reality compound, comprising motor and, prob- 

 ably, lobus vagi roots, as well as lateral-line fibres. 



Burckhardt (11) has designated the most dorsal root of the 

 Acustico-facialis " VII," and attributed to it a motor character. 

 There can be little doubt that this is in reality the preauditory 

 lateral-line root, and the error noted above (p. 162) has been 

 here repeated. (See, also, page 185.) 



The following table shows the probable homologies of the 

 preauditory lateral-line roots in the descriptions of these inves- 

 tigators : 



