393.] 0VERSIGT OVER NORGES ASCIDIAE SMPLICES. 



95 



irrows round the opening The lower part of the body almost 

 iways strongly wrinkled or furrowed, especially the stem 

 art ; the wrinkles here always go, more or less, regularly length- 

 ise. Very } r oung specimens are mostly perfectly smooth. 

 he colour of the specimens, in spirit, light, or dark, grey- 

 rown, more whiteish upwards, and mostly darker in the old 

 lan in the young animals. Two specimens differ somewhat 

 i appearance from the common type, the testa being wrinkled 

 J over length wise and crosswise, the colour also is darker 

 lan common. 



The muscles of the body not very much developed, equally 

 istributed on both sides. 



The mouth, and sevler orifices, in short, closely situated, 

 Lmost quite retractile siphones. The mouth siphons on the 

 oint of the body, the sewer siphon, pulled down somewhat 

 i the back side. The tentacles large, about 20 in number. 

 'orsal organ small, with slightly rolled in horns; the horns 

 irns to the left. 



The branchial sack goes through the whole length of the 

 limal, on each side with 4 folds which converge towards 

 le backwall of the branchial sack; thi first fold (nearest the 

 orsal fold) large st, strongly proje eting, and with 12—15 

 iternal longitudinal bars; 2 nd stretches forward a little, and 

 as but 4—5 bars; 3 rd again large, with 6—8 bars, whilst4 th 

 about 2 nd size with 4 bars. Between the folds 2 — 3 strong 

 ad projecting internal longitudinal bars; transverse arteries 

 f 3 or 4 different sizes and limits together with the internal 

 'ngitudinal bars meshes, which are generally double the 

 ngth of the breadth, and have 14 — 16 spira cles (the greatest 

 teshes), (fig. 18). 



The dorsal fold long, the edge smooth, disappears a little 

 elow the swallow. The swallow, which has a rafcher fchick 

 id long lip on each side, is removed from the branchial 

 -ck's hindmost part by a distance equal to 1 /z of the bran- 

 lial sack's length. The esophagus goes almost perpendicularly 

 •^iiwards, is narrow, and sharply defined towards the sto- 



