124 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



Nephridia. — Nephridial tubules extend anteriorly just about as 

 far as anterior margin of dark band of integument, and are confined 

 to a very short portion of the body. Anteriorly there are fine 

 tubules which ramify on the external wall of each of the lar^e 

 lateral vessels, and encroach considerably on its lumen. The fine 

 tubules are collected into a single longitudinal duct on each side, 

 which passes posteriorly along the dorsal wall of the lateral vessel. 

 This longitiulinal duct is often nearly as large as the blood vessel 

 itself when contracted, and after passing posteriorly for a compara- 

 tivel}^ short distance opens on the dorso-lateral surface of body by 

 a large efferent duct. 



Blood system. — The pair of very large cephalic lacunae are 

 united anteriorly by a broad, median lacuna. Lateral vessels of 

 large size, situated in esophageal region in the angle between 

 esophagus and proboscis' sheath and often closely applied to the 

 latter. Consequently special rhynchocoel vessels are very much 

 reduced or completely wanting. At intervals, however, sieve-like 

 diverticula from the lateral vessels ]>ass partially or completely 

 through the muscles of proboscis sheath and spread out beneath the 

 inner epithelium of the latter. In the most anterior esophageal 

 region lateral vessels lie internal to delicate inner circular muscles, 

 but soon pass outside it. Esophageal lacunae referred to in a pi-e- 

 vious paper (Coe, 'SS'', p. 517) probably exist only as artifacts, and 

 do not appear in more recently prei)ared sections. 



Nerves and sense organs. — Cephalic nerves well developed, as are 

 also the esophageal and dorso-niedian nerves. Inner dorso-median 

 nerve and ventral nei've much reduced. When body is much con- 

 tracted lateral nerve cords are often forced out into the integument 

 to some extent. 



Cerebral sense organs little developed, and are represented merely 

 by specialized epithelium in very slight grooves adjacent to dorsal 

 brain lobes. In a previous paper these are erroneously referred to 

 as "side organs " (Coe, '95^ p. 517). 



Lateral sense organs fau-ly well developed, but not as highly 

 specialized as in C seoi'lineata (p. 114), or in Carinomella (p. 142). 

 Relative position of these sense organs and efferent nephridial ducts 

 is somewhat varied. In some specimens the sense organs lie 

 entirely in front of nephridiopores, while they sometimes extend 

 beneath and sometimes a little behind the latter. As stated above. 



