THE Leeches (hirudinea) 



657 



42 (39) No copulatory glands; penis filamentous; colors variable, dorsum 

 usually green with six or four brown stripes, sometimes 

 broken. European medicinal leech; introduced. 



Hirudo medicinalis Linnaeus 1 7 58, 



Fig. 1004. Birudo medicinalis. External morphology from the dorsum. The numerals on the right 

 indicate the annuli, those on the left the somites, the index lines running to the neural annuli; 

 isl P. and J-/A P., first and last nephridiopores. Natural size. (After Whitman.) 



43 (38) Jaws variable, sometimes rudimentary or absent; teeth when 



present all or partly in double series; gastric ceca one large 

 posterior pair only. Chiefly predaceous 44 



44 (47) Jaws short and high; teeth small, only partly in two series; no penis; 



genital orifices separated by three or four rings, surrounded 

 by systems of gland pores . Philobdella Verrill 1874. . 45 



45 (46) 



Denticles about 35; narrow median dorsal and broader marginal 

 yellow stripes and a few brown spots. 



Philobdella gracile Moore 1901. 



Philobdela takes the place of ^ocro- 

 bdella in the Gulf States and has 

 singular habits. It is the native 

 "blood-sucker " of that region. 



Fig. 1005. Philobdella gracile. A , external 

 genital orifices ( ^ , 9 ) with their re- 

 spective systems of gland pores (cgp $ 

 and cgp 9 ) ; np, nephridiopores; sbm, 

 vl, vm, submargmal, lateral, and median 

 sensillae. X 3^. (After Moore.) B, 

 outline of a jaw with teeth. X 35. (After 

 Moore.) 



46 (45) Denticles about 20; no median dorsal stripe and no spots; two 



faint stripes of reddish brown separated by a narrow line of 

 blackish on each side of dorsum. 



Philobdella floridana Verrill 1874. 



47 (44) Jaws rather small and retractile into pits or absent; teeth when 



present coarse and all in double series; penis filamentous; 



genital orifices separated by five rings; no copulatory glands. 



Eaemopis Savigny 1820 . . 48 



48 (51) Jaws and teeth present 49 



