THE LEECHES (HIRUDI.VEA) 



17 (18) 



18 (17) 



19 (22) 



20 (21) 



I 



653 



I'lacobdelh pediculata I k-miiiKway 1008 

 Anus behind XXVII; posterior segments normal. 



Placobddla is. sir.). . ,g 



Cutaneous papillae smooth and round. 



Integuments opaque, deeply niemonfr.rl ."n .. ^ 



leii ^ ^ ' ^y pigmcnicd m a conspicuous pattern 



ol ohvc green and yellow; annulus 

 ^ without trace of a secondary 

 furrovv; size large. Common on 

 Lnelydra, etc. 

 Placobddla parasitica (Say) 1824. 



One of the best known of our leeches 

 most often found clinKinK in lanrc 

 numbers to the naked skin at the base 

 of the hind leRs of the .snapping turtle 

 whose I)lood they suck. LarRe in.li- 

 yiduals measure fn.m , to 4 inches 

 ong in partial e.xtension and arc very 

 broad, thm, and fohaceous. When 

 bearing eK«s or young the>' often leave 

 the host and for a time lead a free li/e 

 m ponds and streams, feeding ofj 

 worms and lar\ae. Eggs and youn« 

 are borne m large numbers and it is 

 an mterestmg sight to obser\-e the 

 crowded family of youngsters actively 

 bending and turning on the venter of 

 the parent, the thin margins of whose 

 body are mrollefi to form a i)rotccting 

 fold. The color patti-rn is rich and 

 striking, theground color of dull green 

 or ohve green standing in sharj) con- 

 trast to the bold and characteristic 

 markings of yellow by which it is re- 

 placed to a varjing degree. 



Fig. 998. PlacobdrUd parasitica. Kxtemai 

 metamerism, central lunous system, re- 

 productive organs, etc. l-.VXVII — 

 somites; mg, ol. I. m. marjiinal. outer 

 lateral, lateral and median srasill.ic re- 

 spectively; pkg.^ \ i.h.ir>n>:c.il kLiwIs; 

 0€, esophagus; v, atrium or s|irrma(o- 

 phore sac; d, ductus eiaculatorius; ri, 

 vesicula seminalis; <J and 9. male 

 and female jwrcs; tdc. vas deferens. /. 

 testes; ov, ovary. X J. (Redrawn 

 from Whitman.) 



, 'XAIV 

 t • ' XXV 



XXVI 

 XXVII 



21 (20) 



22 (19) 



23 (26) 



Integuments translucent, brightly but not deeply pigmented with 

 green, orange, and white; a^ of complete somites with a 

 distinct secondary cross-furrow; size medium. 



Placohdclla picta (\'crrill) 1S7J 



Cutaneous papillae prominent and rough or pointed :: 



No marginal papillae on caudal sucker 



