NOTES ON SOME AQUATIC OLIGOCHATA. DALLA: 
Fic. 31.—A transverse section of a sperm-rope, from a series of longi- 
tudinal sections of the worm. a, 4, ¢, d, as in Fig. 29. 
Fic. 32.—View of genital segments of a spent worm, seen by transparency. 
Drawn from living specimen. JD. v. Dorsal vessel (the dilatation is not a 
permanent feature, it merely represents a diastole of the vessel). G. 
Intestine. ov. Ovary. sp.s. Shrunken sperm-sac, with convoluted blood- 
vessel on its wall. spts. Degenerating spermatheca, ¢. Testis. v.v. Ventral 
blood-vessel. 
Fie. 33.—Diagrammatic side view of Psammoryctes, to show arrange- 
ment of chete. 
Fie. 33a.—A palmate cheta from dorsal bundle of anterior segments, seen 
from in front. 
Fic. 334.—Same in optical longitudinal section to show curvature of free 
edge. 
Fic. 838¢e.—A multidentate cheta from dorsal bundle. 
Fic, 33d.—A forked cheta from ventral bundle, anteriorly. 
Fic. 33e,—A forked cheta from ventral bundle, posteriorly. 
Fie, 34.—Diagrammatic side view of Tubifex. 
Fic. 34 a, b,c, d.—Multidentate chet from anterior segments, dorsal 
bundle, after treatment of the worm with KHO and mounting in glycerine. 
b is a young cheta; the others were in use. 
Fic. 35.—A diagrammatic side view of Limnodrilus, Clitellio, and 
Hemitubifex. 
Fic, 35a.—A dorsal cheta. 
Fic. 36.—A diagrammatic side view of Spirosperma and Ilyodrilus 
Perrieri. 
Fic. 36¢.—Cheta from dorsal bundle of Ilyodrilus Perrieri, 
Fic. 36 4.—Ditto from other species, 
Fic. 36¢.—Palmate cheta from dorsal bundle of 3rd segment of Spiro- 
sperma. 
Fic. 36d.—Palmate cheta from hinder segments. Same magnification 
(the lines are too coarse). 
Fic. 36¢e.—A ventral cheta, 
Fic. 367,—A ventral cheta from one of the anterior six segments. 
Fig. 37,—Outlines of chitinous coat of penis of various genera, after 
Claparéde, Kisen, and Vejdovsky. a. Hemitubifex. 6. Telmatodrilus, 
c. Psammoryctes and Spirosperma. d, Limnodrilus corallinus, 
e. L, igneus, f. L. alpestris. gy. L. Hoffmeisteri. 4. L. silvani. 
