54 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
The crop bears seven pairs of lateral diverticula, as in G. elegans and the 
closely related European G. complanata, with both of which this species has 
many points in common. The first pair of diverticula arise in the anterior or 
middle part of somite x11. and are two or three lobed, the anterior lobe being 
prolonged forward through somites x11. and x1. The five following pairs of 
crop diverticula arise in the middle of somites xtv.—xvim. respectively, and 
are usually bilobed distally. The last (seventh) pair of crop diverticula ex- 
tend far back of their origin in somite xrx., often into somite xxm. They 
give off secondary lateral diverticula, a pair in each of the somites through 
which they extend. 
The crop diverticula are often a conspicuous feature of this species when 
viewed in a living condition from the ventral side of the animal, for numerous 
large green chromatophores aggregate about the crop and show through the 
clear ventral body wall the form of the crop outlined in green. 
f. Nepuropores, NERVOUS System. 
The nephropores (nph’po., Figure 36) open ventrally, anterior to the middle 
of the sensory ring of a somite, as stated by Whitman (91°). They are present 
in the eighth and all the following triannulate somites. 
I have nothing new to add to Whitman’s (’92) excellent account of the cen- 
tral nervous system. It is important to notice, however, the arrangement of the 
ventral capsules in the brain region (Figure 36). Those of neuromeres 111.—VI. 
all lie in a single row in the median plane; that is, have what I have called the 
tandem arrangement. The ventral capsules of neuromere I. (2, 2, Figure 3 b) 
have the side-by-side position found in all the species examined by me. 
Figure 3 a is a dorsal view of the brain and shows that the supra-cesophageal 
commissure in the species lies far forward in what may well be regarded as 
its primitive position. 
The less crowded condition of the brain capsules in this as compared with 
other species is interesting, as showing that the smaller the leech is, the more 
crowded are its brain capsules likely to be (compare page 50). 
g. PAPILLE, COLORATION. 
I have reserved to the last, in describing this species, the discussion of papil- 
le and coloration, for it is on the basis of these characters alone that I am able 
to distinguish two varieties, plana and rugosa, which I find associated together, 
but apparently without intergrading forms, in collections from Cambridge, 
Mass., Lake Chautauqua, N. Y., Lake Forest, I]., and Wellsville, Kan., a very 
wide range extending across the Mississippi valley and the Atlantic seaboard. 
(1) Var. plana Clepsine plana Whitman, ’91*). 
This variety has a relatively smooth skin, which bears dorsally small dome- 
shaped papill@, the most conspicuous of which are placed as indicated by stars 
