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



fms, stones and clay, 2 sps (August 23, 1864). — Spb. Exp. 1868: Liefde Bay, 10 

 —30 fms, 1 sp; Ice Fjord, Green Harbour, 40—50 fms, clay, 1 sp; D:o 4 sps (Feb- 

 ruary 31, 1872, Mus. G.). — Spb. Exp. 1872-1873: Spitzbergen, without definite 

 locality, many sps; Norway Islands, 15 — 25 fms, clay, many sps; Foul Bay, 10—25 

 fms, 4 sps; Smeerenburg Bay, 25 fms, stones and clay, 6 sps; D:o sand, stones and 

 algae, 1 sp, depth 1 fm. 



Arctic North America: 76° 9' N— 68° 28' W, 30—45 m, mud, 2 sps along with 

 Dendrodoa aggregatet (July 5, 1894, E. Nilson). 



General Distribution. 



Styela rustica is common along the whole coast of Norway, bottom various, 

 depth down to about 110 m (Kiaer 1896, Bjerkan 1908). It is met with off the 

 coasts of the Danish Islands and Sleswig-Holstein to Travemunde, Iceland and the 

 Faroe Islands (Traustedt 1880), Sweden, Gullmarn (Carlsson 1918). In the Arctic 

 Sea its occurrence is almost circumpolar. This species has not been hitherto recorded 

 from the Bering Sea, as far as Styela macrenteron Ritter may not be a synonymous 

 form or a variety (Hartmeyer 1903, 1919; Redikorzew 1910). Off the east coast 

 of North America it is found to the north of the New England coast. (Van 

 Name 1912.) 



Remarks. 



The examined specimens do not show great variation as regards the typical 

 characters, though they vary in other respects especially as to the test and the form 

 of the body. The form of the body is generally elongated, cylindrical, sometimes 

 rounded, dorso-ventrally flattened. The latter form is not often met with among 

 full-grown individuals. Therefore it will be worth mentioning that specimens col- 

 lected off Kola Peninsula belong to that type. They are rounded and low, dorso- 

 ventrally depressed and often covered with Hydroids. (Pl. 1 fig. 2.) From the east 

 coast of N. America, the Gulf of St. Lawrence, specimens of the same peculiar form 

 have been recorded. According to Van Name (1912) they are characterized by 

 small a size and low, conical shape, two individuals were almost disk-like. The pre- 

 sence of the pointed process of the test between the apertures and above all the 

 internal anatomy prove, however, that they are identical with Styela rustica. 



The test is always of leathery consistency, more or less thick. In living speci- 

 mens from Gullmarn it is of a light-reddish colour. The surface of the test is variable. 

 Generally it is deeply wrinkled, sometimes the wrinkles are substituted by rather 

 sharp processes. Not seldom the surface is transversally folded, or it is almost 

 smooth. The presence of the pointed process between the apertures may be inde- 

 pendent of the condition of the test surface; it occurs in individuals with a smooth 

 test as well as in individuals with a wrinkled test. Its presence is not constant, as 

 is known. Judging from the collections examined, it occurs in most cases. 



Under the name of Styela macrenteron a new species apparently closely allied 



