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



The second fold of thc lett side is substituted by one to two longitudinal vessels. 

 One, sometimes two, intermediate vessels. Gonad four- or five-branched. Stomach 

 elongated, not distinctly marked off from the intestine, externally smooth-walled. 



var. subpedunculata Rittek 1899. 



2. Branchial sac without intermediate longitudinal vessels. The folds 

 are reduced, the second fold being substituted by two or three 

 longitudinal vessels. Gonad usually four-branched. 

 Test with characteristic longitudinal lists and wart-like processes. 



D. lineata Traustedt 1880. 

 II. Testis separated from the ovary. 



Branchial sac with one fold developed ou each side. Test translucent and somewhat incrusted 

 with sand. Fine attacbing filameuts, especially on the 



under surface. 1). uniplicata Bonnevie 1896." 



a. Opening of the dorsal tubercle semi-circular. forma typica. 



b. Opening of the dorsal tubercle horse-shoe-shaped. var minuta Bonnevie 1896. 



(*eogranbical and bathynietrical distribution and general observations. 

 Mus. G. = Museum of Gothenburg; sp(s) «= specimen(s). 



Styela gelatinosa Traustedt 1887. 



Distribution: Kära Sea, 50—70 fms, Dijmphna Exp. 1882 — 1883 (Traustedt 1887). — Between the 

 Faroe Islands and the Orkney Islands, 60° 37' N— 5° 42' W, 588 m, Valdivia Exp. (Michaelsen 1904). — 

 N. W. of the Faroe Islands, 480 m (Bjerkan 1905). 



Styela doliolum Bjerkan 1905. 



Syn.: Styela rustica? Bonnevie 1896. 



Distribution: Norway, Lofoten, off K0st, 827 m, North-Atlantic Exp. Iö76 — 1878; W. of Aalesuud, 

 62° 53' N— 4° 14' E, 820 m; D:o 62° 58' N— 1° 56' E, 1,100 m. — Between the Faroe Islands and the Shet- 

 land Islands, 1,130 m. (Bjerkan 1905, 1908). 



Styela rustica Linné 1767. 



Pl. 1, figs. 1 — 2. 



Syn.: Ascidia monoceros, Möller 1842. 

 » » Särs 1851. 



Cynthia nisticu, Ålder 1848. 

 Cynthia aggregat a, Kupffer 1875. 

 Tethyum nisticnm, Hartmeyer in Br<>nn's Tierreicb. 

 » Van Name 1912. 



Habitat : 



West coast of Siveden: Bohuslän, without definite locality, many sps. — Gull- 

 marn, numerous sps (1871 Loven, 1873 Stuxberg, 1882 Théel); Kristineberg, 8 

 sps (Zool. st.); D:o many sps (1854 Mus. G.); Löken, 6 sps (July 13, 1852 Mus. G.); 

 Flatholmen, 1 sp (May 1890, Aurivillius) ; Lysekil-Stångehufvud, 1 sp. (July 1876); 



1 This spccies is provisionally referred to the genus Dendrodoa from wliicb it differs in many typical 

 respects. 



