1906.] 



NERVES OF CHLAMYDOSELACHUS ANGUINEUS. 



963 



impossible to state whether the present condition of these canals 

 is vestigial or rudimentary. It is certain, however, that the con- 

 dition of all the canals, but especially those in this region, is ver}- 

 unstable. The canals vary in their length, course, and diameter. 

 The neuromasts, both as regards number and position, are very 

 variable, but in every case they are supplied by dorsal bi'anches of 

 the lateralis vagi. In the specimen from which II. (text-fig. 140) 

 was taken, lines {s, s) appeared to be drawn on the skin ; these 

 were found to be due to the scales, which were triangular in shape 

 and arranged in two parallel interlocking lines, exactly as the 

 scales are ai'ranged above all the open canals. These " lines " 

 may represent either the first step towards the formation of new 

 canals or the last step in the degeneration of canals. The latter 

 is the more probable, as if the former were the case we should 

 expect to find neuromasts present, but so far neither neuromasts 

 nor nerves have been traced. 



Text-fi2-. 140. 



L.L.R 



Variations in Lateral Line Canals of Chlamydoselaclius. 



I., II. Commissural canal. 

 III., IV. Ventral view of Hyomandibular canal under the lower jaws. 

 V. Lateral canal in region of dorsal tin. 

 C.C.A., C.C.B. Anterior and posterior portions of Commissural canal. 



H.M. Parts of Hj'omandibular canal. 

 L.L.R., L.L.L. Lateral canal on right and left sides. 



It is worth noting that the specimen from which II. (text-fig. 140) 

 was drawn had also covering scales arranged in lines, dorsal to, 

 and at right angles to, the lateral canal. These "lines" oc- 

 curred at irregular intervals for a distance of 3 cm. The scales, 

 which produced the appearance of lines, may be remnants of a 

 condition in which the main canal had lateral branches. This 



