188 <A. E. Verrill—North American Fresh-water Leeches. 
cephalic lobe, beneath; maxille similar to those of Hirudo, but 
more prominent; a plicated cesophagus, similar to that of 
Aulastomum ; a stomach most like that of Hemopis ; internal 
reproductive organs similar to those of Hirudo; while the 
» external male organ is more like that of Hamvpis. The genus 
iffers from all the others, however, in the situation of the 
genital orifices, in the form of the maxille, the number of 
plications in the cesophagus, ete. It includes one of the 
stoutest, largest, and most powerful of the leeches hitherto 
described. 
Macrobdella decora Verrill. Figure 4; a maxilla. 
Hirudo decora Say, Long’s Second Expedition, vol. ii, p. 268, 1824; 
tema Helm., i, p. 474; Leidy, Proc. Phil. Acad. Nat. Sci., 1868, p. 
_ Body large, stout, broad, considerably depressed throughout; 
in extension much elongated and gradually tapering anteriorly, 
strongly annulated. Length of the larger 
Diesing, Sys 
230. 
Fig. 4. 
very prominent, higher than broad, outer edge rounded in fron 
and finely and closely denticulate (figure 4). Below each max 
illa, in the oesophagus, is a broad plication or fold, which divides | 
.mto two a short distance beyond; alternating with these 4% 
formed upon the 
there are conspicuous rugose elevations on the 86th and 37th, 
and on the 88th and 39t 
