THE EAK. 



399 



buted the R. zacculi (r#) from above; a large otolith rests on the 

 macula and occupies a large portion of the cavity, more especially 

 the lower portion. The tubular iluctv.% endotymphaticus (cle) arises 

 by a narrow oval opening placed in the upper and inner part of the 



249. 



ii. 

 in. 



IV. 



The membranous labyrinth of Sana aetilenta ; after Retzius. 



Part of membranous labyrinth to show relations of the ductos and aaccus tndolympharicu- 



t<> the cochlear part ; magnified. 



The recessus utricnli and the external ampulla ; magnified. 

 To show tegmentum vascnJosnm, pan baaQaris, pan negfeeta, etc. 

 To show relations of the cochlear part to the pars negfecta. 



aa. Ampulla anterior. 



at. Ampulla extema. 



al. Apertura lagenae. 



ap. Posterior ampulaL 



apn Apertura partis neglectae. 



au. Apertura union! i. 



ca. Canalis m. anterior. 



r" xtemal semicircular canaL 



cp. Posterior semicircular canaL 



cpb. Opening into pars basilarU. 



IT. Crista acustica. 



cut. Canalis utriculo-saccularis. 



de. Ihictus endolymphaticus. 



dp. Dnctus perilymphaticus. 



'. 



rap. Ramnlus amp. posteriori*. 

 rt. Ramulus baaOaria. 

 utriculi. 



Ram ohw lagenae. 

 Ramnloa negfeetna. 

 Ramos posterior. 

 Ramuraa saccolL 



MM. Macula ac. recessus utri- 

 culi. ree. 



m. Macula ac. neglecta. rt. 



mp. Membrana basilaria. m. 



pb. Pars ba&ilaris cochleae. rp. 



pe'. Dark spot on either aide of rt. 

 crest of ampulla. *. 



pi. Pars ac. lagenae. rp. 



pit. Pars neglecta. 



ppb. Papilla ac. basilaris. rpl. Saccus psrilymphrtiroa 



ra. Ramos anterior. 



raa. Ramolus amp. anterioris. 



rat. Ramulus amp. externa. 



Posterior semicircnlar 



Sinus ntriculi superior. 

 Tegmenrum Tascnlomun. 

 Utricle. 



wall, runs upwards and to the angle between the utricle and the 

 *inu* superior, continues in the same direction for a short space, and 

 then curves inwards to pierce the apertura aqitaeductus restibuU, and 

 so reach the cranial cavity. It then forms a large, thin- walled sac 



