ENCHYTR^EID^E 59 



Setae. The setae diminish slightly in size towards the dorsal and 

 the lateral intervals respectively. No setae in somites XI and XII. 



Spermathecce (fig. 31, #). The ampulla connects with the intes- 

 tine in V and is considerably swollen, furnished with thin walls. The 

 duct muscular, exterior surface striped longitudinally. 



Sperm-ducts. As the specimen was sectioned transversely the size 

 of the funnels is not known. The sperm-ducts narrow, apparently 

 not very long, repeatedly folded. The atrium and the penial chamber 

 of nearly equal size, the atrium slightly the larger. The absence of 

 atrial glands a distinct feature. In the penial chamber some few glands 

 opening independently of each other around the pore of the duct, 

 enclosed by the muscular coat of the lower part of the sperm-duct. 

 The penial glands are powerfully developed and crowd the bulb to the 

 utmost. Between the glands are muscles and connective tissue. 



The nephridia were too macerated to be described satisfactorily. 



MESENCHYTR^EUS SOLIFUGUS Emery. 



pi. vn, fig. 8; pi. vni, figs, i and 2; text-fig. 32. 



1898. Melanenchytraus solifugus EMERY, '98. 



1899. MesenchytrcEus solifugus MOORE, '99. 



Definition. Length 12 mm., width .5 mm. Somites about 50. 

 Setae : anteriors about 4, 5, 3 ; posteriors, 2, 3, etc. Prostomium 

 rounded, blunt and small. Clitellum probably confined to XII. Sex- 

 ual papillae prominent. Septal glands small. Spermathecae straight, 

 with three diverticles in the same plane at the center of the organ. 

 Sperm-ducts comparatively broad, extending at least as far back as 

 XV and probably farther. Funnels cylindrical, folded on themselves, 

 contracted at the center. A large atrium in which opens about eight 

 atrial glands of large size. Many large accessory glands open along 

 the base outside of the penial bulb. About fifteen penial glands inside 

 the penial bulb. Nephridia with three large lobes and a long ante- 

 septal. Lymphocytes small, pointed, ovoid. Color intensely brown- 

 ish-black owing to pigment which permeates most of the inner organs 

 as well as the body- wall. 



Locality. Occurs on the ice of many of the glaciers of Alaska. 

 Collected by Prof. Trevor Kincaid and Prof. W. E. Ritter on the 

 following glaciers : Muir Glacier, June n ; La Perouse Glacier, June 

 18. Specimens have also been described by Prof. J. Percy Moore 

 from the Malaspina Glacier. 



Note. Professor Moore partly describes another ice worm, M. 

 niveus Moore, from the Malaspina Glacier, said to differ in hav ng 



