The Latero-Sensory Canals and Related Bones in Fishes. 467 



111 Batraclius tau and Lopliins piscatorius aiTaiigemeiits of the 

 latero-sensory system are found that are markedly different from any 

 of those so far described. 



In Batrachus those infraorbital organs that correspond to the 

 otic and third buccal gTOups of organs of Amia, are, as I have al- 

 ready pointed out in an earlier work [2, p. 173], represented by 

 the otic and suborbital pit organs of Clapp's descriptions; while the 

 first and second groups of buccal organs of Amia, are represented, 

 in Batrachus, by the maxillary and antorbital lines of organs. The 

 middle portion of the maxillary line is alone, of all these organs, 

 enclosed in a canal. There accordingly is, in all probability, no 

 dermal postfrontal and no otic latero-sensory component of the 

 squamosal in this fish. The post-preopercular, or glossopharyngeal 

 latero-sensory component of the squamosal of Amia, is apparently 

 represented in Batrachus by the "tough fibrous or semi-cartilaginous 

 covering", which is said [21, p. 230] to enclose the short so-called 

 temporal section of the main infraorbital canal, and which lies on 

 the outer surface of the muscles, wholly separated from the under- 

 lying squamosal. Two "free organs" on the top of the head are 

 said to probably represent the supratemporal canal of Amia, a third 

 free organ to probably represent the middle head line of pit organs, 

 and still another to represent the anterior head line. The main 

 infraorbital line of Batrachus is said to be "continued on to the body 

 as the dorsal line of free organs", but these free organs must not be 

 confounded with the dorsal body line of my descriptions of Amia, 

 that line being said to be represented in Batrachus by a still more 

 dorsal line of four free organs. The line of free organs that forms 

 the posterior continuation of the main infraorbital line is said to be 

 innervated by the ramus recurrens facialis, and not by the nervus 

 lineae lateralis vagi, the latter nerve taking no part in the inner- 

 vation of the organs of the three lines on the side of the body 

 excepting to "send branches to some of the scattered organs of the 

 middle line". The composition of the ramus recurrens is not at all 

 clear in the descriptions, and Clapp, herself, does not venture to 



definitely homologise it, saying, however [p. 236], that: "It seems 



30* 



