100 



JOHAN KIÆR. 



Microcosmus glacialis, M. Sars, 1858. 

 (Fig. 31—34). 



The body is almost globular, slightly compressed fror 

 the sides, and free, not attached to the bottom (fig. 31 

 The largest specimen gives the following measure: heigb 

 33 mm., Length 33 mm. Breadth 27.5 mm. Distance betwee 

 the basises of the siphons: 3 mm. The length of the testa : 

 cleft: 22 mm. The testa is thm but tough, translucent, whitisl 

 and closely covered with fine and coarse sand, shell fragmeni 

 &c, with the exception of a furrowed naked mesh whic 

 stretches into the longitudinal axis of the body and include 

 the mouth-and-sewer siphon. „By the animal's contractio 

 this naked space can be folded together from both sides Hk 

 a split and thereby completely closed". (M. Sars). The test 

 isbesides, on the underside, furnished with numerous fasteninj 

 threads, which appear to serve in fastening the animal tott 

 bottom as a kind of root sucker. Mouth-and-sewer openin 

 upon not quite retractile siphons, which are situated rath* 

 dose together in the middle of the cleft. In extended stai 

 the mouth siphon is about double the height of the other. Tl 

 muscular body itself is thin, and nearly transparent. Tl 

 muscles, equally distributed on both sides, form and opt 

 network, and disappear almost entirely on the underside ; ti 

 animal is attached to the testa, only about the openings. " 

 large and small, strongly pinnatified tentacles. Zona præbra: 

 chialis is smooth, and very broad; it is narrowest on the dors 

 side, by the dorsal tubercle, becomes gradually broader towar 

 the belly side, and here goes into a point by the hypobra 

 chial furrow, whose blind sack penetrates somewhat insi< 

 zona præbranchialis. The dorsal tubercle small, but mm 

 raised, without rolled in horns The dorsal fold with who) 

 smooth edge, very long, and passes the swallow on the h 

 side. On the right side of the branchial sack 5 strong lort£ 

 tudinal folds, on the left only 4, the 5 th being represent» 

 only by a few, closely situated, internal longitudinal bai 



