32 AUGUSTA ÄRNBÄCK-CHRISTIE-LINDE, NORTHERN AND ARCTIC INVERTEBRATES. 



and from five to six on the right. The testis and the ovary are not separated; 

 they form one cylindrical body, the male glands being placed on the outer side and 

 the ovary on the inner side of the gonad. The testis opens beside the ovarian 

 aperture at the end of the gonad. The openings are directed towards the atrial 

 siphon. (Cf. Pl. 2, fig. 22.) 



Redikorzew has given the following description of the reproductive organs in 

 C. rhizopus: »Die Gonade ist beiderseits entwickelt; das Ovarium und der Hoden 

 sind getrennt. Das Ovarium hat die Gestalt von langen cylindrischen Schläuchen; 

 — an einigen davon bemerkt man deutlich einen kurzen Ausfiihrungsgang — den 

 Oviduct. Die Hodenbläschen sind sehr zahlreich, auf der Bauchseite ziehen sie in 

 zwei Reihen längs der Mitteilinie hin.» »Die Hodenbläschen» of which the author 

 speaks, are endocarps, which are present in a great number; that is clearly shown 

 from the above-mentioned figure. 



C. rhizopus (incl. var.) is found in the Arctic region, occurs also in the Boreoarctic 

 mixture zone, and has been collected once and in three specimens in the Boreal region. 

 Its range of distribution comprises the western Arctic Sea of Siberia, West Spitz- 

 bergen, East Greenland, Novaja Zemlja, the Murman coast and Cattegat. The last- 

 mentioned locality is noticeable and further investigations should be of interest to 

 make out whether its occurrence there is accidental or it may be a relic form, no 

 locality being known, yet at least, between the Murman coast and Kummelbanken 

 in Cattegat. Tvvo closely allied forms are known before from the North Sea region 

 viz. Styela vestita Stäng er (syn. Cnemidocarpa mollis Stimpson) reported from 

 the north-eastern British coast (Northumberland and Durham) and Cnemidocarpa 

 mortenseni Hartmeyer of which one specimen has been dredged in Skagerrack 58° 

 6' N — 9° E, 660 — 420 m (»Norska rännan»). The three specimens of C. rhizopus 

 collected in Cattegat are of small a size, the largest one measuring 12 mm in length. 

 Two are mature, in the third the gonads are thin and only a little developed. The 

 branchial sac and the alimentary canal are of typical structure. As to the external 

 appearance they are elongated, the test is rather thick, incrusted with sand grains 

 and with numerous rhizoid-like processes arising from the posterior part of the body. 



C. rhizopus has been dredged from 5 to 60 fms. Ordinary bottom, mud with 

 sand or stones. 



Cnemidocarpa rhizopus var. murmanensis Redikorzew 1911. 



Pl. 1, fig. 21. 

 Syn. Tetliynm rhizopus var. murmaneme, Redikorzew 1911. 



Habitat: 



Kära Sea: 73° 53' N- 69° 20' E, 10 fms, sand, 3 sps (August 10, 1875, N. 

 Zemlja Exp. 1875, Tiiéel & Stuxberg). 



