440 THE AMERICAN NATURALIST. [Vor. XXXVI. 
which Kolliker’s form has been placed by Joubin, Biirger, and 
others, that the establishment of a new genus is imperative. 
Carcinonemertes gen. nov. 
Parasitic nemerteans living on various species of Crustacea. 
Body small, slender, often filiform, rounded, and of about the 
same diameter throughout; head without distinct lateral 
grooves, not demarcated from body. Body not usually coiled 
or much twisted, but often folded sharply so that the anterior 
portion of body lies parallel and in contact with the posterior 
portion. Mouth and proboscis open together; cesophagus 
extremely short, opening broadly into the intestine through 
a large muscular chamber situated immediately behind the 
brain (Fig. 6); intestine broad, with short lateral pouches 
which are but little developed in posterior portion of body. 
Proboscis sheath without muscular walls, consisting merely 
of a thin membrane closely applied to the small proboscis. 
Proboscis but little developed, very small in size, and extremely 
short, without lateral pouches of reserve stylets, but armed with 
central stylet and basis only. Central stylet minute, usually 
one-third to one-half as long as basis, which is small and slender. 
Stylet region of proboscis can be withdrawn but little behind 
brain; consequently anterior chamber is very short, without 
distinct muscular layers, without distinct nerves, and without 
a thickened glandular epithelium such as occurs in almost all 
other nemerteans. Stylet apparatus imbedded in a strong 
muscular enlargement provided with numerous large glands 
(Figs. 2-4). Chamber immediately behind stylet, small but 
muscular, and with a lining of flattened epithelium, while 
the posterior proboscidial cavity is very short, often almost 
spherical, highly glandular, connected closely with the rudi- 
ments of the proboscis sheath and imbedded in the connective 
tissue which lies internal to the body musculature. 
Cerebral sense organs probably wanting. Ocelli 2 (occa- 
sionally fragmented into 4). 
Cephalic glands massively developed ; a remarkable develop- 
ment of submuscular glands extends throughout the whole 
