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



off the coasts of the Danish Islands, common along the whole west coast of Sweden, 

 especially in Gullmarn, and Norway, and is also found in the Baltic Sea as far as 

 Bornholm on the east. On the American Atlantic coast it is common in the southern 

 Boreoarctic mixture zone about the Bay of Fundy region and even in Casco Bay. 

 S. loveni usually occurs on stony bottom on shells, or in mud with stones. 

 Depth varying from a fevv metres to about 630 m. 



Styela bathybia Bonnevie 1896. 



Distribution: N. of Jan Mayen, 75° 12' N— 3° 20' E, depth 2,195 ra, temperatnre — 1,57°C. (The 

 Norwegian North Atlantic Exp. 1876 — 1878). 



Styela theeli n. sp. 1 



Pl. 1, figs. 5—9. 



Habitat: 

 Norivay: Hardanger, Samlenfjord, 350 fms, rocks, 1 sp (July 23, 1880, Bovallius). 



Deseription. 1 



External Appearance. 



The specimen is of elliptical outline; the body is dorso-ventrally flattened and 

 attached by the left side by an expanded base. The apertures are placed at the 

 anterior end of the animal and not far apart. They are four-lobed and surrounded 

 by small papillae and folds of light colour. Wrinkles in the test prevent them from 

 being easily distinguished (Pl. 1, fig. 5). The test of the upper side, i. e. the right 

 side, of the animal is of dark-brown colour, coriaceous and wrinkled. It is covered 

 with retracted Bryozoa, whence the surface looks as if it were dotted with tiny 

 whitish tubercles. Some shells of Foramini f era are also attached to it. The surface 

 is free from other foreign matter. The left side by which the animal is attached is 

 whitish and opaque. The specimen measures 34 mm in length and 19 mm in breadth. 

 The expanded base measures 23 mm in breadth. 



Internal Structure. 



The right side of the test is thick and of leathery consistency. The inner 

 surface is smooth and provided with a nacreous lining. The left side — by which the 

 animal is attached — is thin. 



The mantle musculature is powerfully developed on the right side and round 

 the siphons as regards both the horizontal and longitudinal layers. On the left side 

 it is thinner and not so well developed. The oral tentacles are short and conical 



1 In associating with the species the naine of Professor Doctor Hj. Théel, I desire to express my 

 appreciation of the interest he has taken in the study of the Swedish Tunicata. 



2 A preliminary note on this species has been published in Pergens Museums Aarbok, 1919 — 1920. 



