6 AUGUSTA ÄRNBÄCK-CHRISTIE-LINDE, NORTHERN AND ARCTIO INVERTEBRATES. 



arenosa? Forb. and Hanl. is identical with Cnemidocarpa rhizopus Rdkzw., the 

 species labelled Cynthia rustica Mull. is identical partly with Styela rustica L. and 

 partly with Dendrodoa grossularia van Ben. 



In her paper on Ascidians from the Norwegian North Atlantic Expedition, 

 1876—1878, Bonnevie (1896) has described a new Styelid, Styela cylindrijormis. It 

 is characterized by four branchial folds on each side, »the generative organs are 

 developed on both sides in the shape of long, winding, tube-like glands; they are 

 attached to the muscle stratum, and extend so far in a horizontal direction, that 

 they form almost a complete circle. They are hermaphroditic, having ova and sperm 

 developed in different bends.» The specimen was found at Reykjavik. From this 

 description it is not possible to conclude anything for certain as to the structure of 

 the gonad and the relation of the male glands to the ovary. It cannot be decided 

 whether the specimen is to be referred to the genus Styela or to the genus Cnemi- 

 docarpa. A gonad having »ova and sperm developed in different bends» does not occur 

 in any known Ascidian. Bonnevie's description might be interpreted in different ways. 

 It seems to me that the most probable interpretation is that the male glands are 

 separated from the sinuous ovary and situated at both sides of it, in the same way 

 as in Styela loveni with which it agrees in several other respects. Making inquiries 

 about the specimen in the Museum of Christiania where the Ascidians from the North 

 Atlantic Expedition are stored, I was informed that Styela cylindrijormis is not to 

 be found in the Museum. The same answer has been given from the Museum of 

 Bergen. Every possibility of re-examining the species seems thus to be excluded. 

 For that reason, and as the species seems to be dubious and there is an uncertainty 

 as to its classification it is not included in the following synopsis of genera and species. 



