KT7NGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 63. N:0 2. 



31 



The folds of the branchial sac are rudimentary — but more or less as to the 

 first one — and are substituted by groups of longitudinal vessels. (Cf. text-fig. 3.) 

 The number of the vessels is not constant, nor quite the same on each side. The 

 average number might be as follows: 



right side: dorsal lamina — 6 to 7 — 2—3 — 2 — endostyle, 

 left » » 5—2—3—2— 



The above-mentioned number is met with in the upper part of the branchial sac ; 

 towards its bottom the longitudinal vessels are often less numerous, one vessel in 

 each group being reduced. 



...... 





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Text-fig. 3. Cnemidocarpa rhizopus Redikorzew. Part of the branchial sac showing 

 the groups of longitudinal vessels. X3'2. 



According to Redikorzew all folds are rudimentary and the vessels are distri- 

 buted as follows: 



dorsal lamina— 3 — 1—2 — 1 — endostyle. 



No intermediate longitudinal folds have been observed. 



As appears from fig. 22 the alimentary canal is of great length and cha- 

 racteristical structure. The stomach is elongate and curved almost along a right angle. 

 Numerous longitudinal folds — about 20 in number — are visible in its wall. The 

 pyloric coecum is well developed and curved. The intestine forms a U-shaped loop. 

 Its proximal part is provided with longitudinal folds (cf. fig. 22); in some individuals 

 examined these folds are externally less conspicuous than in the specimen figured. 

 The rectum is long and sinuous; a deep plication accompanies it along its whole 

 length. The margin of the anus is two-lipped and densely lobed. 



The reproductive organs consist of four gonads on the left side of the body 



