ZooL.— Vol. II.] RISEN— OLIGOCHMTA. 1^7 



Diplocardia Michaelseni Eisen. 



Diplocardia Michaelseni Eisen, Zool. Bull., Vol. II, No. 4, 1899. 



Definition. — Color, flesh. Size, 45 mm. by 2 mm., hardly tapering pos- 

 teriorly. Somites, 63. Prostomium divides somite I completely. Dorsal 

 pores, most anterior IV/V. Spermiducal pores XIX. Spermathecal pores, 

 one pair preseptal in IX, one pair postseptal and almost central or median in 

 VIII. Prostate pores XVIII, XX. Oviducal pores XIV, in front of and 

 anterior to setae a, close together. Setae all ventral; a-a=3 a-b\ a-a about 

 one-third larger than b-c\ <^-f =about 2 a-b. Penial setae present at spermi- 

 ducal pore. Spermathecal setae present in VIII, IX; setae a and b being 

 differentiated and sculptured. Clitellum ring-like, dorsally XIII-)^ XVIII; 

 ventrally XIV-XVII. Genital zone, a deep central, oval pit in XVIII-XX, 

 surrounded by an elevated ridge. A pear-shaped ventral and median papilla 

 in XXI and >^ XXII, and a similar papilla in >^ XXII and XXIII. Grooves 

 between prostate pores are straight. A pair of deep, round pits in posterior 

 part of XVII. No paired papillae. CEsophagus straight or bent, not widen- 

 ing in any somite. Gizzards VI, VII. A large, thick glandular crop in XIV, 

 XV. Sacculated intestine commences in XVIII. Dorsal vessel single (?), 

 swollen in XVI, XVII. Hearts X, XI. Nephridia, meganephridia. Testes 

 very large in X, XI. Ovaries are digitate. Sperm-funnels in X, XL Sperm- 

 sacs, three pairs, in IX, X, XII. Those in IX are preseptal, those in X and 

 XII are postseptal, in IX only sperm-masses. Oviducts in XIV. Prostates 

 occupy somites XVII-XXI, glandular part contains only one layer of cells, 

 muscular duct folded, glandular part thick. Spermathecal duct muscular, 

 long, folded, pouch large in two divisions; a large, oval, exterior diverticle, 

 pointed forwards. The spermathecae in VIII open anterior to setae, those in 

 IX open posterior to setae. 



Septal formula: — 



VI/VII, VII/VIII, VIII/IX, IX/X, X/XI, XI/XII. 

 Habitat. — I possess a dozen specimens of this very inter- 

 esting species, from Raleigh, North Carolina. Collected 

 by Messrs, Brimley. 



Occurs in swamps and in water under logs together with 

 D. Udei and D. singularis caroliniana. 



In this species, as in D. Udei, there are bundles of glands 

 opening jointly in a pair of circular orifices in VIII and IX, 

 between the sexual spermathecal setae. These glands are 

 interposed between the layers of the body-wall and the 

 epithelial cells, and run parallel with the longitudinal axis of 

 the body. Their structure is described more in detail in a 

 memoir soon to be published by the California Academy of 

 Sciences, San Francisco. 



