22 
D. C. Danielssen. 
[No. i. 
Explanation of the Plates. 
Plate t 
Fig. i. Fenja mirabilis, natural size. 
x 2. Fenja mirabilis, dissected longitudinally, and a little mag- 
nified. a. Longitudinal muscles. b. Mesenterial filaments. 
c. Ovaries. d. Tentacles. e. Oesophagus. f. Intestine. 
g. Rectum. h. Anus. 
» 3. The same. Both the integument and the intestinal canal 
dissected longitudinally. a. Inner surface of the gullet-tube 
with its longitudinal folds. b. Inner surface of the intestine 
with its folds. c. Inner surface of the rectum with its 
folds. 
» 4. Posterior extremity of the animal: magnified. a. Anus. 
b. Papillæ around the anus. c. Folds on the rectum. 
» 5. A portion of the integument of the same viewed from the 
inner surface; magnified. a. Longitudinal muscle with in- 
sertion of the septum. b. Transversal muscles. c. Trans- 
versal muscles which pass under the longitudinal muscle, 
towards the septum. 
» 6. Transverse section of the integument of the same: magni- 
fied. a. Ectoderm. b. Connective-tissue. c. Circular 
muscles. 
» 7. Transverse section of the integument and intestinal canal 
of the same; magnified. a. The mesial portion of the 
septum; the longitudinal muscles are torn away. b. The 
chambers between the septa. c. Longitudinal muscles on 
the body-wall. d. Longitudinal muscles on both sides of 
the septa. e. Fillet-formed prominence on the outer wall 
of the intestinal canal. f. Connective-tissue prolongations 
from the inner wall of the intestinal canal, which form the 
folds on same, g. Epithelium of the same, 
