398 DAVIDSON BLACK 



The first spinal nerve is absent in adult Rana and according 

 to Gaupp the dorsal ramus of the second spinal nerve sends 

 motor branches to the m. intertransversarius capitis superior 

 and to the m. longissimus. The ventral ramus of this nerve 

 has a wide distribution by means of five chief branches: (1), 

 communicating branch to the sympathetic; (2), large branch to 

 the m. intertransversarius capitis inferior; (3), ramus thoracicus 

 superior anterior to m. levator scapulae superior, m, levator 

 scapulae inferior and sometimes to m. rhomboideus anterior; 

 (4), communicating branch to brachial plexus; and (5), a large 

 trunk termed the nervus hypoglossus which innervates the fol- 

 lowing muscles: sterno-hyoideus, hyo-glossus, genio-hyoideus 

 and genio-glossus. 



It is unfortunate that Coghill (17) has not given a detailed de- 

 scription of the distribution of the first two spinal nerves in Triton 

 taeneatus (s. Molge vulgaris) , but in his paper it is implied that 

 the arrangement of these nerves is similar to that obtaining in Am- 

 blystoma. In the latter animal (Coghill, 16) the dorsal ramus of 

 the first spinal nerve sends motor branches to the m. extensor 

 dorsi communis, while its ventral ramus gives off numerous 

 fibers to the m. intertransversalis, fibers to the m. basiscapularis 

 (levator scapulae inferior) and then apparently fuses with the 

 ventral ramus of the second spinal nerve. The motor fibers 

 of the dorsal ramus of the second spinal nerve are distributed in 

 a manner essentially similar to those of the first dorsal ramus. 

 The ventral ramus of the second spinal nerve gives off fibers 

 to the m. intertransversalis, m. thoraci-scapularis and sterno- 

 hyoideus before its junction with the corresponding ramus of 

 the first nerve. The resulting trunk innervates the remainder 

 of the m. sterno-hyoideus and the m. genio-hyoideus. No 

 further mention is made of the distribution of this hypoglossal 

 trunk to other muscles, but Driiner (18) states that all pre-hyal 

 hypobranchial spinal muscles are innervated from this source 

 and Kallius (32) has described both a genio-glossus and a small 

 hyo-glossus muscle in Triton. 



Driiner (I.e.) has noted the presence of a well developed 

 spino-occipital nerve in Triton which emerges through a sepa- 



