160 J. B. JOHNSTON, 
constituting the whole of what we now call the lateral line VII. I 
have shown that in the sharks there is a lateral line root arising 
from the “Lobus posterior” and bound up with the VII proper, and 
wrongly interpreted by Stannıus. This corresponds to the ventral 
rootlet of the lateral line VII in A. ruthenus (T. IT v. of Goro- 
NOWITSCH) and A. rubicundus, and it is possible that there is such 
a root also in A. sturio, so bound up with other roots as to have 
been overlooked by STAnnıus (cf. page 158). To summarize: there 
is present in all three species of Acipenser which have been studied 
and in the sharks studied by Srannius a lateral line root which 
enters a special dorsal thickening of the medulla which is un- 
doubtedly the lobus lineae lateralis (L. trigemini of GORONOWITSCH). 
All these forms (except A. sturio?) agree also in the presence of a 
second lateral line root from the tuberculum acusticum. This latter 
is the only root of the lateral line VII in Teleosts. 
In the work of later authors there is general agreement as to 
the origin and distribution of the lateral line X nerve. It arises 
always from the tuberculum acusticum and requires no further 
attention here. The roots of the lateral line VII have been described 
in sharks, Ganoids, Teleosts, Protopterus, and the tadpole. In sharks 
GEGENBAUR (71) describes two roots, one from the lobus trigemini, 
the other from the acusticum (Hexanchus). JACKSON & CLARKE (76) 
describe two similar roots in Echinorhinus. Ewart (89) describes 
in Laemargus 1) the ophthalmicus superficialis VII as arising from 
“the so-called trigeminal nucleus which occupies the most dorsal 
portion of the medulla”, and innervating certain ampullae and mucous 
canals. 2) The buccal arises dorso-caudal to the trigeminus (hence 
probably from the acusticum), communicates freely with the oph- 
thalmicus superficialis VII, and is distributed to ampullae and mucous 
canals. The ophthalmicus VII sends a component into 3) the common 
trunk of the palatine and hyomandibular and it is presumably these 
fibres which innervate ampullae and canals supplied by the hyo- 
mandibular. STRONG must be in error in speaking of 2) and part 
of 3) as lateral line roots. Certainly 1) and 2) are lateral line roots, 
and I see no evidence that 3) contains any lateral line fibres other 
than those received from 1). CoLE (96a) describes, in Chimaera, 
the superficial ophthalmic VII as having a ventral root and the buccal 
as having a dorsal root. Both supply ampullae and canals. The 
hyomandibular receives an anastomosis from the buccal and also 
supplies ampullae and canals. This agrees with Ewart’s description, 
