No. 472] 



ANATOMY OF CRYPTOBRANCHUS 



the elasticity of the cartilaginous fourth bar allows coi 

 variation in the size of the loop and consequently in the .- 

 gill slit. The anterior end of the third bar is united, f( 

 distance, with the posterior bone of the second bar by 

 tough membrane that was noted in connection with tlic 

 terior arches. 



The Vcrfrhral Column 

 The vertebral <<.Imiui of the AuM-ricini 



42 bones or vertebra'. The giant sahunan- 

 der of Japan, according to Osawa, has in 

 its vertebral column forty-five vertebne, 

 besides two cartilaginous rudiments at the 

 tip of the tail. The vertebra? may l)e divided 

 into three sets: those of the body, of w liidi 

 there are 19; those of the tail, 1!) to 2 in 

 number; and a single vertebra between these 

 two sets, the sacrum. The number of body 

 vertebne, as might perhaps be expected, 

 seems to be more constant than the number 

 of caudals, though the variation in the latter 

 may be partly due to the great difficulty of 

 I)reserving the last few vertebra^ on account 

 of their small sixe and cartilaginous nature. 

 All of the vertebral centra, with the excrp- 

 tion, of course, of the ant.Tior.urfa.e of the 



niddle of the centra. 



length is about tui<',- its oTeai<-i diameter. 



Like all of the other body vertebra-, except the first, thi 



