OXFORD UKIVERSXXY SPITSBERGEN" EXPEDITION. 



1123 



In anotlier specimen both organs appear to be confined to 

 segm. vi. 



Besides these organs, which have, from their texture, more or 

 less the appearance of nepliridia, there is behind the pharynx a 

 narrow divei'ticulum of tlie alimentary tube, wedge-shaped or 

 conical as seen in longitudinal sections, pointed above, directed 

 dorsalwards and backwards, and at its tip connected with a pair 

 of solid Icnobs, the postpharyngeal bulbs. Each knob is a cellular 

 mass, ovoid or somewhat club-shaped, with the long diameter 

 continuing the direction of the diverticulum. The length of the 

 diverticulum is 120^, that of the bulbs 36 /x, and the thickness of 

 the latter 20 yii. 



Text-fiirure 1. 



1 oes. 



chL 



~v. nepi 



bi.-'- 



V. n. c. 



Henlea {Henlea) hrucei; transverse section tlirougli cesopliagus and hinder end of 

 ventral OBSopliageal nepliridium. Bl., blood in sinus-like cavities of nepliridium ; 

 clil., clilorag-ogen cells; oes., ossopliagus; v.n.c, ventral nerve cord; v.neph., 

 ventral cesopliageal nepliridium. 



The oesophagus is narrow as far as segm. viii., Avhere it swells 

 out into the intestine. The canal is thenceforward s swollen seg- 

 mentallyin an ovoid manner, and is not constricted in the genital 

 segments. There are no chylus-cells. 



Chloragogen cells begin, but only scantily, in the posterior part 

 of segm. vi. 



In segm. viii. is a pair of oesoplmgeal diverticula. Each is sac- 

 like, with folded walls; each originates from the aJimentarv tube 

 at the hinder end of the segment, a,nd extends forwards to its 

 anterior limit. There appears to be some variation in the exact 

 manner of origin of the sacs ; in two series of sections, both lon£>-i- 

 tudinal, the sacs have independent openings into the cesophagus, 



