No. 463] NORTH AMERICAN INVERTEBRATES. 431 
= 
N 
O N 
o 
» 
b 
oa 
[^] 
DNE 
N 
Deep red, mahogany, or red 
Order Heteronemertea, 
Proboscis musculature of two layers, of which the outer is circular ; 
muscular crosses absent in proboscis; cephalic glands usually ver 
voluminous, extending posteriorly behind the brain; cephalic furrows 
absent : ; . T&NIOSOMA. 
. Proboscis musculature of two or three layers, of which the outer is 
longitudinal; muscular crosses present in proboscis ; cephalic glands 
usually but little developed, and not extending posterior to brain . 2. 
. Without horizontal cephalic furrows on sides of head; caudal cirrus 
present à : S ; ; ; ; ^ . ZYGEUPOLIA. 
With conspicuous horizontal cephalic furrows on sides of head 
Caudal cirrus absent ; proboscis sheath usually considerably shorter than 
4 
Caudal cirrus present; proboscis sheath usually extends nearly or quite 
to posterior end of body : ; ; ; ; ; ee 
Body remarkably thick and massive, usually nearly cylindrical when 
fully extended, but very broad and much flattened in intestinal region 
when strongly contracted ; ocelli wanting; muscular layers of body 
possess a reddish tinge . EUBORLASIA. 
ge ; i à ; ; 
. Body long and slender, rounded or flattened, very contractile ; ocelli 
present in most species : . LINEUS. 
. Body rather firm, lateral margins not remarkably thin; incapable of 
M 
swimming ; neurochord cells absent in many species . . MICRURA. 
. Body usually long and ribbon-like, much flattened, with very thin lateral 
margins and well adapted for swimming ; dorso-ventral and diagonal 
muscles well developed ; neurochord cells present in many species 
CEREBRATULUS. 
TANIOSOMA. 
. With narrow transverse rings of white throughout length of body. 
Body of moderate diameter, but of great length, often exceeding 2 
meters, somewhat flattened; brown, with a great number of narrow 
rings of whitish encircling the body . T. mexicana Biirger, E. 
Without white rings A i ; : : : : 2. 
Yellow, thickly sprinkled with small, irregular, dark red spots; body of 
very large size, sometimes 2 meters or more in length and 18 mm. 
in diameter : ; ‘ ; : T. princeps Coe, A, P. 
dish brown, sometimes covered with whitish 
bloom ; head with broad spot of darker color and terminal border of 
white; ventral surface of same general color as dorsal, but paler, 
except ventral side of head, which is whitish ; body large, soft, flabby, 
40 to 60 cm. in length T. punnetti Coe, C, S. 
