414 DAVIDSON BLACK 



caudal part of the VII + VIII complex and which apparently 

 derives some of its fibers from the motor V nucleus while others 

 arise from the posterior longitudinal fasciculus. The conclu- 

 sions indicated here are evidently opposed to those of Gaupp, 

 and since his deductions are also largely based on the obser- 

 vations of Schulze, further study is desirable to decide this 

 point. 



Note on the fasciculus solitarius. Kappers (38) has pointed 

 out that in contrast to other ichthyopsidans, a predominatingly 

 descending character of the IX-X portion of the fasciculus 

 solitarius is to be observed for the first time in amphibians. 

 He came to the conclusion that the descending course of the 

 IX-X sensory roots in amphibians was e\adently not due to the 

 neurobiotactic influence of any gustatory centers, but has prob- 

 ably resulted from the necessity for general \dsceral sensory 

 correlation in the upper cervical segments on account of the 

 presence in this region of the motor nuclei innervating the 

 tongue musculature and especially those innervating certain im- 

 portant respiratory muscles. On account of its importance as 

 a respiratory correlation tract, Kappers pointed out that the 

 fasciculus solitarius apparently merited its old name 'fasciculus 

 respiratorius'. Wallenberg (57) has noted that descending 

 fibers of the fasciculus solitarius may be traced as low as the 

 third cervical segment in the frog, and since this is below the 

 level of the motor segment innervating the aspirator muscula- 

 ture, its important respiratory nature may be doubted. 



In amphibians certain parts of the pulmonary mechanism, 

 in addition to their primary respiratory function, are also con- 

 cerned in the production of sound. The sound producing ap- 

 paratus in amphibians is most highly developed in anurans 

 though by no means restricted to these forms. It consists 

 essentially of a vibrating mechanism in the larynx and a mech- 

 anism providing for the forcible expulsion of air from the lungs. 

 In the frog, where this apparatus has been most extensively 

 investigated, it has been found that certain muscles of the body 

 wall (pars scapularis of the obliquus externus and the rostral 

 part of the m. transversus) are especially fitted to aid forced 



