886 ME. WAITEE E. COLLrNGE ON THE SENSOET [DeC. 17, 



elastische Fasern beigemischt sind. Mitten durch die Kapsel 

 geht noch ein weisser, aus Bindegewebe gefertigter, 1^ Liniea 

 dicker, fester Strang, der von einem knorpeligen Fortsatz des 

 Kopfbnorpels komnit und zur Befestigung und Erhaltung der 

 Form der Kapsel wesentlicb beitragt. Die bezeicbnete Kapsel ist 

 angefiillt mit einer hellen Gallerrmasse, und in diese eingebettet 

 liegen die Ampullen der Scbleimkanale. In der Gallertmassesieht 

 man ansser Kernen noch Bindegeu ebsmascben und elastische, oft 

 in weiten Bogen isolirt verlaufende Fasern, welche alle sowohl mit 

 der Wand der Ampullenkapsel als aucb mit den Ampullen selber 

 in Yerbindung stehen, und die Befestigung derselben innerbalb der 

 Gallerte sichern." 



2. Structure and Varieties. 



I have quoted Leydig at some length, for his account is the 

 first and only one that makes any pretence at detail. Judging 

 from Leydig's description and figure, he only met Avith one 

 form of canal, whereas there are three distinct types. 



In the occipital group the number of pores varies from seven to 

 eleven, each leads into a long tube or canal which widens out into 

 a sac-hke base (PI. LIII. fig. 9, a), the ampulla being ill-defined. 

 In some cases where the pores of the canals are in a row and the 

 canals or tubes run parallel to each other, some are longer than 

 others, the length from the pore to the base of the canal varying 

 as follows : — 



and 



of the first seven pores (PI. LIII. fig. 9, a). 



In the supra- and sub-orbital groups the pores are more closely 

 grouped. Each leads into a narrow tube which passes do^\•nwards 

 and with its fellows opens into a single wide tube ; this con- 

 tinues for a short distance and then terminates in a spongy mass of 

 ampullae (PI. LIII. fig. 9, 6). The whole of the spongy mass is 

 enclosed in an ill-defined connective-tissue capsule. In the 

 maxillo-mandibular groups the canals approach more nearly to 

 those described and figured by Leydig, and it seems very probable 

 that he examined only those in this region and in the region of 

 the Y-shaped commissure. 



Thus in Chimcera it will be seen that there are three types 

 of ampullary canals, viz. : — (1) A simple unbranched tube which 



