472 Edward Phelps Allis jr., 



excepting', perhaps, in Lopliius. Raia hatis and Raia laevis also both 

 differ from Mustelus in that the so-called median canal is transverse 

 instead of longitudinal in position, while in Raia ocellata the similarly 

 named canal is longitudinal in position. These two canals, one longi- 

 tudinal, and the other transverse in position, are certainly not morpho- 

 logical equivalents, but what value is to be attached to this difference 

 in position I can not determine. About one half of the Batoidei 

 described by Garman here agree with Raia laevis, the other half 

 agreeing with Raia ocellata. In two of the Selachai also, Alopias and 

 Prionodon, the median canal is said by Garman to be transverse; 

 being longitudinal in all the other species described. 



In Torpedo that part of the main infraorbital canal that corres- 

 ponds to the otic section of Mustelus, belongs in part to the canal 

 of the ramus oticus and in part to the canal of the nervus lineae 

 lateralis vagi; but whether this latter part of the canal contains any 

 sense organs, innervated, naturally, by the nervus lineae lateralis vagi, 

 or not, is not stated by Coggi. 



In Laemargus, the supraorbital canal anastomoses with (Ewart) 

 or approaches closely (Garman) the dorsal end of the postorbital 

 portion of the main infraorbital canal. There is then a short break 

 in the latter canal, and then a short section of canal that lies anterior 

 to the supratemporal canal, and. that is innervated, one half by the 

 ramus oticus, and one half by the supratemporal branch of the ner- 

 vus lineae lateralis vagi. The median canal is longitudinal in position, 

 as in Mustelus. 



In Chimaera, the latero-sensory organs all lie in open grooves 

 instead of in closed canals. The supraorbital groove anastomoses, by 

 its hind end, with the supratemporal groove, and not with the main 

 infraorbital one. No portion of the latter line, anterior to the supra- 

 temporal groove, is innervated by a postfacial nerve, Chimaera agree- 

 ing in this with Mustelus. The suborbital part of the main infra- 

 orbital line is separated into two somewhat parallel lines; one of 

 which is innervated by the so-called inner buccal nerve of Cole's 

 descriptions, and the other by the outer buccal nerve; the two lines 

 probably corresponding respectively, as I have already stated in a 



