220 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
extended, the body is always flattened, quite unlike the thick rounded form assumed by Hsemopis, etc., 
when contracted or resting. The largest extended specimens are over 3 inches long. The selected 
type specimen has the following dimensions: Length, 55 mm.; greatest width (about xvm), 8.5 mm.; 
greatest depth, 3.8 mm. (about); diameter of sucker, 5.4 mm.; width of upper lip at base, 2.3 mm. 
There are 105 distinct annuli, counting one which appears posterior to the anus. In many 
specimens most of them are marked by a transverse depressed line, making them faintly double. The 
annuli are smooth, in no case exhibiting the prominent papillae so characteristic of the species last 
described, although in some cases examples of the two species had been killed and preserved together. 
In marked contrast to Hirudinaria blanchardi the mouth is relatively small. The upper lip is 
slightly wrinkled on the margin, but nearly smooth below, and undivided by a median sulcus except 
at the base. Dorsally it is seen to consist of the first four somites, the coalesced annuli of the fifth 
bounding the mouth posteriorly. 
The five pairs of conspicuous eyes (pi. 13, fig. 10) are disposed as usual in the family. The dif- 
ferent directions toward which their pigment cups face is especially evident. The first pair look 
directly forward, the second forward and slightly outward, the third outward, the fourth outward and 
backward, and the fifth backward and slightly outward. 
The male pore is situated on a small, more or less prominent cone rising from the contiguous 
parts of somites xi and xii, between which the orifice lies. In no case does a penis protrude, and 
there are no copulatory glands. The female pore opens through the middle of the fourth annulus 
(55) of somite xii. (PI. 13, fig. 12.) None of the specimens show a clitellum. 
The anus has the usual position behind somite xxvii, but xxvm appears as a distinct ring bound- 
ing it behind. The sucker is relatively small, thin, very flat, rather narrowly attached, and much 
more broadly free posteriorly than anteriorly (pi. 13, fig. 11). The usual 17 pairs of nephridiopores 
appear as short oblique slits on the posterior margins of annulus 52 of every somite from vm to xxiv, 
inclusive (figs. 10 and 11). The first 16 pairs are just ectad of the ventro-marginal sensilke; the last 
pair is peculiar in being distinctly more mesiad. 
Annulation. — The details of annulation are sufficiently shown in the diagrams (pi. 13, figs. 10, 1 1). 
Attention is directed to the following points: Somites ii and m are very short, with no trace of more than 
one annulus each. The second annulus (a3) of iv is sometimes very imperfectly separated. On the ven- 
tral surface v is uniannulate and vi biannulate. viral is very large, but always entirely undivided; 
xxvi «1 is separated at the margins at least, the first annulus (al + «2) of xxvii is very broad, and 
its sensilke are far posterior, and, lastly, xxvm appears as an annulus distinct from the sucker. 
The metameric sensillfe (pi. 13, figs. 10 and 11) are small and round as in Hsemopis and 
Hirudo medicinalis, but are generally easily found. The dorso-lateral are much larger than any of the 
others. Their arrangement is shown in the figures, the three ventral pairs on somite xiv (fig. 10). 
Sensilke are very numerous on the dorsal surface of the sucker, all of the eight dorsal series being well 
represented. As usual, they are variable in number and position and show evidences of multiplication. 
Color. — The pigmentation is described from formalin specimens, which have probably faded 
considerably. The colors are very quiet and the pattern simple, but both tint and arrangement 
vary greatly. The ventral surface is of a uniform ash, which sometimes has a distinctly reddish tint, 
in which case there is likely to be a slight submarginal band clouded with black. A narrow yellowish 
band varying in intensity extends along each margin. Dorsally, the ground color may be just like 
the ventral or it may be darker or tinged .with yellow. In a typical example there are three pairs of 
dark longitudinal bands, which together occupy about two-thirds of the width of the dorsum and 
unite at the ends of the body. They are of an olive color bordered by narrow margins of brown. The 
innermost pair are the broadest and are separated by a narrow but distinct line of yellowish. The 
intermediate pair is slightly and the lateral pair much narrower, and the latter is frequently broken 
and interrupted by intrusions of the ground color. Between the dark bands the intervening strips of 
ground color are very narrow, and broken here and there by bridges of the dark pigment, which cross 
more frequently between the lateral and intermediate bands. Such connections are most likely to 
occur on the fourth annuli of somites, but the pigmentation of this species appears to have no constant 
metameric characters. All of the dark bands coalesce in a single spot of pigment which surrounds 
the anus and extends onto the sucker in the form of a crescent. 
The extreme of color on the one hand is found in a type in which the pigmented bands become 
of an inky black, the median yellow line is almost obliterated, and an additional dull black supra- 
