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bulletin: museum of comparative zoology 



walls. These constitute the so-called submuscular glands, and dis- 

 charge their secretions directly through the overlying muscular 

 layers to the surface of the body. 



The submuscular glands are usually limited to the head region of 

 the body (Text-fig. 19), but in some instances extend backward 



throughout nearly the whole length of the 

 esophageal region, as in Amphiporus nehii- 

 losus (Text-fig. 3), or quite to the intestinal 

 region, as in Emplectonema hilrgeri. As 

 is the case with the true cephalic glands, 

 the submuscular glands are compound, each 

 consisting of a number of gland cells hav- 

 ing a common duct leading to the exterior 

 (PI. 20, fig. 123). 



Caudal Cirrus. 



In addition to the pair of peculiar cirri 

 which Verrill ('92) has described for 

 Nectonemertes, and which are situated 

 immediately behind the head, the only 

 appendage found on the body of any ne- 

 mertean is the caudal cirrus, or caudicle. 



This appendage is found only in the 

 genera Valencinura, Zygeupolia, Mi- 

 CRELLA, MiCRURA, Cerebratulus, and 

 DiPLOPLEURA, all belonging to the Hetero- 

 nemertea. It represents a slender prolon- 

 gation of the body beyond the opening of 

 the alimentary canal. This organ has been 

 very fully studied in Zygeupolia by Miss 

 Thomjtson (:02), who finds it to be pro- 

 vided with both circular and longitudinal 

 muscles more or less continuous with the 

 two inner muscular layers of the rest of the 

 body, with slender prolongations of the lateral nerves (Text-fig. 4), 

 and with a lai-ge central blood space connecting both with the 

 dorsal and with the latei-al blood vessels of the body. The outer 

 longitudinal musculature, cutis, rhynchocoel, alimentary canal, and 

 sexual organs are wholly wanting. 



Fig. '^.—Zygeupolia littoralis 

 Diagram of posterior end 

 of body, sliowing caudal 

 cirrus with large central 

 blood lacuna (bl); hi, lat- 

 eral nerve, extending into 

 caudal cirrus {In'); re, rhyn- 

 chocoel ; sg, sexual gland; 

 in, rectum; a, anus. After 

 C. B. Thompson. 



