Leeches 



31 



Fig. 12. Characteristics of Macrobdclla decora. A : Details of exterior of 

 anterior and posterior ends showing arrangement of somites (I to XXVII, — 

 X to XXIII inclusive are omitted), annuH (a^-a^ b^-b°, etc.), eyes, segmental 

 sense organs, color markings, suckers, anus, etc. (From Leeches of Minne- 

 sota, Nachtrieb et al, '12). B : Dissection of reproductive organs seen from 

 above, at, atrium or penis sheath; cgl, copulatory glands; de, ductus ejacula- 

 torius ; cp, epididj^mis ; gXI to gXIV, ganglia of the ventral chain ; os, 

 ovisac ; ov, ovary or ovarian sac ; od, oviduct ; ti, t2, first and second pairs of 

 testes or testicular sacs ; va, vagina ; vd, vas deferens. C : Male organs dis- 

 sected and ^^e^ved from the right side. The left sperm-duct retains its 

 natural position ; the right is displaced upward, and the dotted line shows 

 the outline of the atrium before the removal of the layer of muscles and 

 prostate glands, at'i, internal layer of atrium; de, ductus ejaculatorius ; ep, 

 epididymis ; pg, prostate glands and muscles ; p, prostate cornua of atrium. 

 (B. and C. from Hirudinea of Illinois, Moore, '01). 



