A. E. Verrill — Marine JVemerteaus of New England. 449 



layer, wliich is made up of longitudinal fibers arranged in bundles, 

 80 that its inner surface, in the sections, is strongly crenulated, or 

 deeply furrowed ; from the indentations between these bundles nu- 

 merous strong vertical bands oif muscular fibei's extend from the dor- 

 sal to the ventral body-walls, between the internal organs. Toward 

 the margins the muscular layers thin out rather abruptly, leaving 

 the marginal portions thin and without longitudinal bundles. The 

 general structure of the interior of the body-cavity is loose, with 

 many spaces in the porous parenchyma, which is feebly developed, 

 as compared with that of other nemerteans. 



The lateral nerve-trunks are very large and quite interior to the 

 muscular layers. They are situated ventrally, some distance from 

 the edges, and near the commencement of the thin-walled marginal 

 portion of the body. In transverse sections they are elliptical or 

 rounded, with an excentric translucent fibrous core along the dorsal 

 side, thus giving the cellular portion a thick-lunate or reniform shape. 

 The lateral nerves are large and conspicuous even back to the caudal 

 fin, where those of opposite sides unite. 



The median dorsal blood-vessel and the two lateral blood-vessels 

 are well developed and situated nearly as in typical Enopla. The 

 lateral blood-vessels are subventral and only a short distance interior 

 to the nerve-trunks. 



There are no memoranda as to the color of the living specimens. 

 All had been placed in alcohol when first seen by me. One that had 

 been in alcohol only a short time was distinctly salmon, or pale 

 orange, in tint ; the others had lost all color, if they had any when 

 living. They may have been white or colorless, and were doubtless 

 translucent, like many other pelagic creatures. Even in alcohol 

 some of them show considerable translucency, — nearly as much as 

 the larger sj^ecies of Sagitta. 



The largest specimens, when first examined by me, were about 2 '5 

 inches long and '50 wide ; subsequently they have contracted con- 

 siderably by long preservation in strong alcohol. 



The largest specimen now measures as follows : length 38"^'" ; 

 breadth of body O™'" ; vertical diameter of body 2'"'" ; length of 

 cirri 14'"'" ; length of head 4""" ; breadth of head 6""" ; breadth 

 of caudal fin 4'°'". 



Descriptions of immature s^^ecimens : A specimen from station 

 2076 is smaller and more slender than those described above. It 

 has a narrower head and shows scarcely any constriction at the neck. 

 The caudal fin is somewhat elliptical, being widest in the middle and 



