KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 63- HKO 2. 9 



II. One gonad on the left side, tvvo on the right. Ovaries sharply bent, form- 

 ing an angle. Male glands in the form of clusters at the proximal end 

 of the ovary. Dorsal tubercle with two small semicircular openings. Test 

 wrinkled. Body dorso-ventrally flattened. 



8. theeli n. sp. Pl. 1, figs. 5 — 9. 



III. Two gonads on each side of the body. 1 



Stalked forms. Gonads of the right side of greater length than those of the left side. Oesopliagus 

 short, opening on the dorsal side of the branchial sac. Apertnres near together, at the anterior 

 end. Test tough, leathery. Body elongated. .9. davata Pallas 1774. 



Pelonaia Goodsir and Foebes 1841. 



Internal longitudinal vessels usually placed at a quite regular distance from each 

 other. Opening of the dorsal tubercle horse-shoe-shaped. Test thin, of brownish 

 colour, often incrusted with small grains of sand. Form of body elongated, cylindrical, 

 somewhat tapering towards the anterior end. 



P. corrugata Goodsir a. Forbes 1841. Pl. 1, figs. 10 — 13. 



Ypsilocarpa n. gen. 



Branchial sac with three well developed folds on each side, and one — the se- 

 cond — in a rudimentary state. One intermediate vessel between the folds. Opening 

 of the dorsal tubercle elongated and somewhat curved. Intestine bent almost at 

 right angles. Rectum short and marked off from the intestine. Apertures sur- 

 rounded by elevations covered with minute, translucent tubercles. Test divided into 

 potygons. Form of body ovoid. Y. clipeata n. sp. Pl. 1, figs. 14—17. 



Cnemidocarpa Huntsman 1912. 



T. Branchial sac with four well developed folds on each side. Numerous 

 intermediate longitudinal vessels present. Gonads many on each side, 

 generally tortuous. Pyloric coecum absent. Margin of dorsal lamina 

 raised into small regular teeth. Stomach short, rounded. Opening of the 

 dorsal tubercle horse-shoe-shaped. Test thin and firm. Surface of test 

 smooth, free from foreign material. C. finmarkiensis Kiaer 1893. 



II. Branchial folds more or less reduced. Pyloric coecum usually well devel- 

 oped. 



A. Branchial sac with one well developed fold — the first one — on each side. Intermediate longi- 

 tudinal vessels present only between the dorsal lamina and the (first) fold. Gonads one on 

 the left side, two on the right. Test thin and smooth, free from incrusting material. Fili- 

 form processes for anchoring the animal are present on the ventral side. 



C. mortenseni Hartmeyer 1912. 



B. Branchial folds substituted by groups of longitudinal vessels. No 

 longitudinal intermediate vessels. 



1 This group comprises a great number of stalkless forms. As they do not belong to the fauna which 

 is the object of this report, they are not dealt with in this paper. 



K. Sv. Vet. Akad. Handl. Band 63. N:o 2. ii 



