Article IV. — On the Anatomy and Histology of a New Earth- 

 ivorm {DipJocardia communis^ gen. et sp. nov.). By H. 

 Garman. 



Characters of the Genus. 



Vasa deferentia opening to the exterior behind the cli- 

 tellu^ by two apertures on the ventral side of somite 19. Two 

 copiilatory fossae extend from the middle of the ventral side of 

 somite 18 to the middle of the ventral side of somite 20, each 

 fossa with a pair of long, curved setas and an outlet of a pros- 

 tate gland at its extremities. Internal apertures of the vasa 

 deferentia two pairs; one pair in each of the somites 10 and 11. 

 Seminal vesicles in somites 9, ?10, and ?11. Testes in somite 

 12. SpermathecEe in three pairs, one pair in each of the 

 somites 7, 8, and 9. Ovaries flabelliforra, situated in somite 13. 

 Internal apertures of oviducts in somite 13; external apertures 

 in somite 14. Seta; arranged in four double longitudinal series 

 on the ventral side of the body, each somite bearing four pairs. 

 Oesophagus very short, without calciferous glands. A muscular 

 gizzard in somites 6 and 7. Typhlosole a very slight dorsal 

 fold. Dorsal vessel double, consisting of two tubes fused only 

 at the dissepiments. No subneural blood vessel present. 

 Nephridia tubular, with the nephridiopores in line with the 

 dorsal setae of the external pairs; internal aperture in the 

 somite preceding that in which the gland lies. Brain small, 

 transversely elongated, with slight median anterior and pos- 

 terior excisions. Pra^stomium not completely dividing the in- 

 tegument of the first somite. 



The genus is based upon a large cylindrical flesh-colored 

 species which is common in the black soil of Illinois prairie- 

 land. Its body is made up of from 123 to 165 somites, and 

 reaches a length of a foot. The following account of its 

 anatomy will furnish the means of distinguishing it from other 

 species of the genus which may be discovered. 

 1 



