35 



to see any distinct median groove which could be distinguished from 

 other grooves and folds as a rudiment of the aditus ad laryngem. The 

 laryngeal muscles are well developed, but the connective tissue between 

 the muscles is very feebly developed and partly broken so that 

 especially anteriorly, many of the muscular fibres from both sides 

 mingle, and many insert themselves at the pericard. In the central 

 parts however a thin strip of connective tissue can be seen at which 

 the muscular fibres insert themselves. In Manculus quadridigitatus 

 we thus meet with the most reduced rudiments of the laryngeal appa- 

 ratus. 



In Amhly stoma opacum, on the contrary, not only rudiments of 

 lungs but also a small aditus ad laryngem can bee seen. The latter is 

 about Y2 ïïi"^ long and half as broad when dilated to its utmost. The 

 lungs are small and narrow sacks measuring about 9 mm in length 

 and 1 Y2 in width at the broadest place. (For a comparison may be 

 mentioned that in a Molge vulgaris of about the same length and 

 much less bulk the lungs measured about 21. mm in length.) The left 

 lung extends along the oesophagus and the foremost part of the sto- 

 mach, but does not reach to the spleen, which organ is much broader 

 and nearly as long so that its volume is greater. The right lung is 

 hidden behind the liver. The distance from the aditus ad laryngem 

 to the tip of the lung is about equal to the length of the head. Although 

 the pulmonary system of Amblystoma opacum is complete so far as 

 there is no part wanting, I must regard it as rudimentary because the 

 lungs are so very small and narrow 2 especially when compared with 

 the size of the animal itself, so that is seems impossible that they can 

 suffice for the breathing of the animal. However I do not doubt that 

 they are used for the respiration together with some other organ, 

 which maybe the skin or »la cavité bucco-pharyngienne« as Cam er ano 

 has found to be the case with Salamandrina perspiciUata and Spelerpes 

 fuscus. With Amblystoma opacum we have the fourth subfamily of 

 Salamandridae represented among' those with reduced pulmonary 

 system : 



Subfam. 1 Salamandrinae: /Sa/amawc^rewa^ersjo^ce/Za^a. 



Subfam. 2 Amblystominae: Amblystoma opacum, 



Subfam. 3 Plethodontinae: Pletliodon glutinosus, 



Plethodoîi erythronotus^ 

 Spelerpes porphyriticus, 



2 We meet with a similar occurrence in Chioglossa lusitanica Bocage. The 

 pulmonary system is complete, but the lungs are very narrow and small so that they 

 do not reach to the posterior end of the stomach. It seems very probable that also 

 in this form the bucco-pharyngeal cavity has to partake in the respiratory function. 



2* 



