EXPLANATION OF PLATE XXXIII. 



A, B, C. Animal of Limn&a emarginata Say, var. mighels, Binney. 

 A, from above; B, from below; C, from the right side, showing 

 extended velum. 



D. Genitalia (principally female). 



A, atrium or vestibule of vagina; AL, albuminiparous gland; 

 O, ovotestis; OD, ovisperm duct; PD, duct of prostate gland; 

 PR, prostate; S, spermatheca or receptaculum seminis; 

 SD, duct of spermatheca; V, vagina; VM, retractor muscles of 

 vagina; U, uterus. 



E. Male organs. 



CG, cerebral ganglion; CM, columella muscle; F, vas deferens; 

 P, penis; PG, pleural ganglion; PN, nerve to penis; PS, penis 

 sac; PSM, penis sac protractor muscles; PSN, penis sac nerve; 

 RM, retractor muscle of penis; VD, penis retractor muscle; 

 G, visceral ganglion; VN, nerve to vagina. 



F. Portion of ovotestis, showing blood vessels (x 519). 



G. Cells from the albuminiparous gland (x 519). 



H. Diagrammatic section of intestine; BLV, branch of lateral blood 

 vessel; ELO, epithelial layer of oesophagus; 1C, intestinal cav- 

 ity; LV, lateral blood vessel; ML, muscular layer of oesophagus. 



I. Portion of lung, showing two main vessels and several connective 

 vessels (x 519). 



J. Portion of lateral blood vessel with one branch with its connective 

 plexus (x 519). 



(Bull. Chi. Acad. Sci., Vol. II, No. 3, pi. iii.) 



