508 H. W. NORRIS AND SALLY P. HUGHES 



Herpele and Deniiophis, anteriorly along the ventral border of 

 the ramus maxillaris V and passes medially to its innervation 

 along an anastomosis between the ramus maxillaris V and the 

 ramus palatinus VII, in such a manner as to give an appearance 

 of the muscle being innervated by the ramus maxillaris V, or, as 

 Waldschmidt interpreted it, forming an anastomosis between the 

 ramus maxillaris V and the third nerve (fig. 18, ■md.l + mx.l). 

 A trochlear nerve occurs in Geotrypetes, but its vestigial condi- 

 tion did not peniiit tracing it to its end in the dorsal oblique 

 muscle, in the specimen examined. 



In the larva of Ichthyophis at the stage examined by the writer 

 the tentacle is not yet differentiated, and the retractor muscle 

 of the tentacle has its insertion on the eyeball. The other ocular 

 muscles are as described by the Sarasins (fig. 19). Of the eye- 

 muscle nerves in Ichthyophis Burckhardt found only the oculo- 

 motor. The writers find the oculomotor and abducens, the 

 latter innervating the retractor tentaculi. The trochlearis 

 doubtless exists but it was not recognized. 



The oculomotorius in the adult Ichthyophis is so vestigial that 

 it probably was not seen either by Waldschmidt or by Burck- 

 hardt. The abducens passes through the skull much farther 

 anteriorly than in other caecilians examined; and on emerging 

 enters almost immediately into the base of the retractor tentaculi 

 muscle, thus avoiding the common contact with the Gasserian 

 ganglion. This extremely anterior exit of the abducens may 

 have led to its being mistaken for the oculomotorius, or pos- 

 sibly overlooked entirely. The oculomotorius makes no anasto- 

 moses with other cranial nerves. The statements of Wald- 

 schmidt and Burckhardt to the contrary, i.e. that the oculomo- 

 torius anastomoses with the ramus maxillaris V, may possibly 

 be explained by their having mistaken the anterior part of the 

 ramus palatinus VII for an oculomotorius. But it seems more 

 probable that their oculomotorius was an anastomosis between 

 the ramus maxillaris and ramus palatinus, possibly containing 

 the small motor twig of the ramus mandibularis V {incLl) which 

 innervates the compressor muscle of the orbital gland. No ves- 

 tige of a trochlearis was found in the adult Ichthyophis. 



