552 



flesh-colored. The length varies with the state of contraction and size 

 of specimen from 40 mm. to 75 mm., and under the influence of 

 anesthetics specimens may exceed 75 mm. There is considerable varia- 

 tion in size. Some mature specimens in moderate extension may be 

 50 X 2.5 mm. and others 75 X 3-5 mm. The number of somites in 

 apparently complete specimens varies from 100 to 120, with inter- 

 mediate numbers more common. The setae are closely paired and, 

 posterior to the clitellum, aa is slightly greater than be and five to 

 seven times greater than ah, while ah equals al)out i^ cd, and dd is 

 slightlv less than one half of the circumference. Anterior to the cli- 

 tellum, ab and cd increase a little and be is correspondingly diminished. 

 The clitellum is saddle-shaped and the ventral margin barely in- 

 cludes the ventral set?c. There is a slight increase in the thickness of 

 the hypodermis on the posterior part of XXI, but at the anterior 

 border of XXII there is abrupt increase and the beginning of the cli- 

 tellum proper. There is marked uniformity in this respect among the 

 many specimens examined. In many cases the clitellum ends abruptly 

 at the posterior margin of XXIX, and in others the dorsal part of the 

 clitellum encroaches on XXX but not beyond the middle of the somite. 

 Tubercula pubertatis are lacking. The paired spermiducal pores are 

 located on XV, about one third of the distance from b to e. The 

 swollen glandular areas surrounding the pores are conspicuous, and 

 the distance between the external grooves which separate XV from 

 adjacent somites is about twice as great in the region of the pores as 

 elsewhere. The oviducal pores are small apertures slightly dorsad of 

 b on XI\'. The ne[ihridiopores are in positions similar to those of 

 other Liimbrieidcr. They are near the anterior borders of the somites 

 and some of them are slightly dorsad of b, while others are approxi- 

 mately midway between (/ and the mid-dorsal line. 



INTERNAI, CHARACTERS 



The septa of the anterior somites are but slightlv thickened, those 

 of \'I/\'II. \1I/\1I1, and XTII/XIV being slightly thicker than the 

 others. The alimentary tract is similar in parts and relations to those 

 of other species of Helodriliis. The esophagus is relatively small in 

 diameter in V-IX. The calciferous gland has the usual relations. The 

 esophagus abruptly widens in X, and the two lateral pouches of the 

 gland are formed. Extending from these pouches to the middle of 

 XIV, there are about 40 longitudinal partitions arranged radially 

 around the lumen of the esophagus. The crop is in XV and XVI and 

 the gizzard in XVII and XVl'lI. The "hearts" are in VII to XI, 



