APHRODITA AOULBATA. 



251 



the Belgian shores, and even in our own country. Only shreds of a fibrillar gelatinous 

 substance have been found in it. Grube 1 describes six layers in the organ. 



About six of the anterior cseca may be considered pregastric (Fig. 16 — in 

 contraction). The lateral cgeca of the gut are longer than in Lxtrnatonice or Hermione, 



Fig. 18. 



m.ob„o 



Dissection of Aphrodita aculeata to show the segmental organs (nephridia),, s.o.; d.m., dorsal longitudinal muscles; 

 m.ob.o., outer attachments of the oblique muscles ; m.oh.i., inner attachments of the oblique muscles ; m.b., oblique 

 muscles ; n.c, nerve-cord.— A. T. M. 



and form slender tubes connecting the remarkable caeca near the body-wall and 

 the long moniliform glandular appendage inferiorly with the central system. These 

 tubular portions of the casca are less truly dorsal in their origin than those of the genera 

 mentioned. The woodcut just referred to shows the canal and its appendages in a state 

 of contraction. In the living and fresh condition the parts often present a different 



1 1873. 



