393.] 0VERSIGT OVER NORGES ASCIDIAE SIMPLICES. 99 



The muscles are tolerably strongbly developed, particularly 

 ehind, as usual with outer circluar, and inner longitudinal 

 bre. 



The tentacles plain, alternat ely large and small, about 30. 

 'he dorsal tubercle horse-shoe formed, the horns sligtly 

 irolled; the opening, between these, turns forward. 



The branchial sack stretches through the whole length of 

 le animal, on each side 4 folds that convergs towards the 

 srøjlow. Between the folds 3 — 8 high and narrow internal 

 )ngitudinal bars. The transverse arteries of 4 sizes, the 

 iast of which goes over spiraler in each mesh. The spiracles 

 re lengthened elliptical, sometimes almost rectangular 

 ig. 29). 



The esophagus is very short; the stomach al so is short 

 nd sharply defmed against esophagus and gut, externally 

 -riped; the gut first goes perpendicularly upwards for about 

 3 of the length of the animal, then goes slantingry dowawards 

 )wards the esophagus for thereupon to rise perpendicularly 

 lto the sewer space.- (fig. 28). The gut twist is thus strong, 

 ut somewhat weaker in a couple of specimens. The anus is 

 tuated rather higher than the top most curling of the gut, 

 ;ad has an exténded edge furnished with about 15 laps 

 ig. 30). 



f The genital organs consist of numerrous small, rather 

 rregularly formed hermaphroditic genital glands, (on the 

 pt side 10); they resemble small elongated groats (fig. 28) 

 rad are fastened to the skin muscles foldas inner side, and 

 )Osely attached to it. That part of the gland that turns out 

 )wards the branchial sack, is an ovarium, with a plain, wart 

 raped opening in one end; the opposite side consists of 

 umerous testicle sacks ; from these, on each side, proceed 

 bout 3 fine export passages upon the upper side of the ovary 

 ad here unite in a single canal, which has its export opening 

 a a small wart close behind the occiduct. 



