192 Tranmctious. 



17. Whitman. 1886. " The Land-leeches of Japan." Quart. 



Journ. Micr. Sc, xxvi, 317. 



18. Whitman. 1891. " Spermatophores as a Means of Hypo- 



dermic Impregnation." Joiirn. Morphology, iv, p. 361. 



19. Whitman. 1891. " Description of CTe^'sme p^awa." Journ.. 



Morph., iv, p. 407. 



EXPLANATION OF PLATES VIII AND VIIIa. 



PlacobdeUa maorica. 



Fig. 1. Ventral view of a much-contracted specimen (much enlarged). 

 The head is bent downwards and shows the eyes. A short 

 distance behind the tip of head is the male pore. 



Fig. 2. Diagrammatic view (or analysis) of the dorsal surface of the 

 anterior end. The annuli are numbered on the left and the 

 somites on the right side. 



Fig. 3. Similar analysis of the hinder end of the body : a, anus ; s, pos- 

 terior sucker. 



Fig. 4. Diagram of the alimentary system, showing segmental positions 

 of the parts (scale half that of figs. 2 and 3). Some of the 

 somites are numbered. The outline of the anterior sucker 

 is indicated by the broken line, ci, c'^, first and last caeca 

 of the crop ; eg, the enveloping gland of crop ; cr, cro]) ; 

 gl, pharyngeal glands ; i, intestine ; mo, mouth ; ph, pharynx 

 in the pharyngeal sac ; st, stomach ; t^, t^, the first and last 

 testicular sacs, in true position. 



Fig. .5. Plan of the genital organs (on same scale as figs. 2 and 3) : at, 

 atrium ; d.ej., ductus ejaculatorius ; od, oviduct ; o%\ ovary ; 

 s, spermatophoral sac; s.v, seminal vesicle; t^, t^, the first 

 and last testicular sacs. 



Hirudo mauiana. 

 Fig. 6. Anterior end ( x 4), showing pattern and position of eyes. 

 Fig. 7. Ventral view of entire leech ( X 1). 

 Fig. 8. Ventral view of imder-surface of the anterior end ( X 7). The 



lower hp has been sUt through, and the cut edges turned aside. 



The sucker has been stretched lengthwise, h.w, body- wall ; 



(7I, first ventral ganghon exposed ; /, jaw ; m, muscles of 



jaw ; or, anterior or oral sucker. 

 Fig. 9. One of the jaws ( x 40, camera drawing). 

 Fig. 10. The anterior portion of the genital organs ( X 4J). The median 



organs are represented as turned aside, alb, albumen gland ; 



ep, epididymis ; g^, the sixth ganglion of the ventral chain ; 



ms, muscular (? spermatophoral) sac; n.c, nerve -c or d ; oi\ 



ovary ; p, penis-sac ; pr, prostate ; t^, first of the ten 



testicular sacs of the left side ; vt, uterus ; v.d, vas deferens; 



H. antipodum. 



Fig. 11. The genital organs ( X 4) : alb, albumen gland ; at, atrium ( =pros- 

 tate-F penis sac) ; ep, epididymis ; g^^^ gi8^ the sixth and eighth 

 ganglia; n.c, nerve -c or d ; ov, ovary; <i, f, fii'st and last 

 testicular sacs ; v.d, vas deferens. 



Fig. 12. The median portion of the genital organs turned aside ( X 8) : 

 cj the atrium (penis-sac) penetrating body-wall to open ex- 

 ternally ; ? , the vagina (vg) penetrating the body-wall to 

 open externally. Other letters as before. 



