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A--Glossiphonia stagnalis D--Placobdella parasitica

B--Glossiphonia complanata E-~Haemopis grandis

C--Macrobdella decora F--Erpobdella punctata
G--Haemopis marmoratis

‘a GEOLOGICAL AND NATURAL HIsTORY SURVEY OF MINNESOTA

Henry F. NACHTRIEB ZOOLOGIST

THE
LEECHES OF MINNESOTA

PART I. GENERAL ACCOUNT OF THE HABITS AND
STRUCTURE OF LEECHES
BY
HENRY F. NACHTRIEB

PART Il. ANATOMY OF PLACOBDELLA PARASITICA
BY
ERNEST E. HEMINGWAY

PART III. CLASSIFICATION OF THE LEECHES OF MINNESOTA
BY
J. PERcY MOORE

ZOOLOGICAL SERIES NO. V

read camer 3)

JANUARY 1912
MINNEAPOLIS MINNESOTA

THE BoARD OF REGENTS OF
THE UNIVERSITY OF MINNESOTA

ilenorable john Lind, Minneapolis: .2 224 o22.022+6+ ee ee eo 1914
The President of the Board.

George Edgar Vincent, LL.D, Minneapolis. .......... 5%: Ex-Officio
The President of the University.

Honorable Adolph QO: Eberhart, Mankato........5..5-+2.4. Ex-Officio
The Governor of the State.

Eenotables ©. Gs schultz, Saint Paul. Jik. .. shee eos Ex-Officio
The State Superintendent of Public Instruction
ElonordiblemWwerleWiayO;, Rochester. ses tert es sere ere 1913
Honorable Milton M: Williams, Little Falls.<.:.2. 2-2-2 =. : 1913
Elonorablerhenny is. 1oviand, Wimath, 2.3 eee. arrester IQ14
Etanorablesne te ice. Willmar. 2.2). so ose ee cba weer IQI5
onotable Charles: .. Sommers, Saint Paul.2.0.)25-5-/7. 3s -- IQI5
Honorable B. F. Nelson, Minneapolis........ wens Abate ee 1916
lonoranic bietce Butler, Saint Pauli: .i2: osc a. eee oe 1916

Honorable Charles A. Smith, Minneapolis......... ates AoE ae 1916

LETTER OF TRANSMITTAL

University of Minnesota,
December, 1910.
To The President of the Board of Regents of the University of Minne-
sota .

Sir:—I herewith submit to the honorable Board of Regents the
manuscript of a report on The Leeches of Minnesota with the recom-
mendation that it be published and distributed.

The general part of the report was written by myself. The
special paper on Placobdella pediculata, a new species parasitic on
one of our food fishes, was prepared by Dr. E. E. Hemingway
while pursuing graduate studies in the Department of Animal
Biology.

The systematic part of the report is based on the material and
notes collected by the Zoological Survey in Minnesota and was pre-
pared by Dr. J. Percy Moore, an American authority on leeches.

The report constitutes “Zoological Series, No. V” of the re-
ports of the Zoologist of the Geological and Natural History Sur-
vey.

Very respectfully,
Henry F. Nachtrieb,
Zoologist of the Survey.

CONTENTS

APA a> oo ARR a ee OP Ie ae aA 7 A I
POAROMOMMRER ENTS: «Sod ce 35 alk elaine o e(shere 2 > ale cyerien ee oo eeiargnmare inal
IMS Che COMMA TISTINICC AL? 5 Merch cian totere Mie loueiers. el eave. seelese ution eras LN
Mable OMmmeontentsS ... i... scauet sane NA ok et AV
SEES AICIEN Poe an a TIE EST OS SAD MEE P VHiMeS cy Tats Wil
Pact [ise LoTR alee Daa eee uO Pea es Os a se oe aoe rte Ie A
GaemetolamatrOd CEO eum ceeaehon Ries etociac «em Bees one ee ohm 3
TELA otis, 0 eee ne ale Nine a en SO ce Artin OMe Rr rE tern 3
Ey COMOnMG LTAPOTLAIICE) 9 2... dyo ele bi eho eieyieit vel saa moe oe goane 5)
escetsaimenMaraclense: cits aekeee peaches sigue! 3.5 ee oeechev eens eyterene 8

Mfistece cat allay TA LOTUNVino:ssr ame s-d une tenses o.8) ok sleyes oy hiss le yegec’ t= Vehe etek af

larcom cick xp lATLALIONS): c2t0 tae tention sis noes © can 23
eeirty Dal ements epee yrs soo cs, si Ans conte aeete weaned s osha acne ene eters 29
introduction and Methods: ...2 se. do ee es + Bee ete ee = 31
iacopdellaspediciulata. «(Habits y.g. 0-1 - cre ee 33
PSSM CLO Me, Sr =~ cuslelagys o/s sekaporolsvede si dneee SteRon a tatoreNsterenen nal 30
Anatomy. Historical Sketch- ...--.'.5.-.22.- sees 36
Central Nervous System, .jc2 4... ae ei eee: 40
[ERE es Sane ne ee er RADIO ea slicre pein Cec OTe 47
INEPEOUUICtIV OLZANS glk qed ae. ook melerse ie a) gat 47
(GlainGIS Ei Eien stenttares GNIAR te eS Sen em PS SSCIS a Cy Coke ec 49
IN| SiDIANGIG TE tee nce cea ene rani cies Gets Magn sorts 50
iecmaiduel xlaiMatiONS a) s..c4e).. 1s. + bs syedseusbersuet ea uae eres 53
iar INCL, OX ESTE Sh Sea enn ROUEN RNC nec rLCpeeit ac wires 0. 63
Hea ONCUCLC HELIN: geese hcie cake al cts ove alas oie aly afhetoe fellan shea lata tare eaten 65
Keyan the SPECleS <<)... ch eeiceie ce ties pn te 69
Descriptions of Families &c.
Glossiphonidzes 22 he. 8 ses See ee oe i ee ae (6
Clossipltomia sce scree a2 = cio ses aan 75
leo De llaor: Ga. shen) ase s ey icf ays eevee ne ee 84
fellemiClePStS 2-5 x sd « «5 oe oe ee ee pile 96
fiehthyobdellida.... 2.4... oe ne 98
INCEMOUCel a. foc curs sd «a iecle cee de se eae ct gie oe ore 99
12 Heyes lola ce Gee eae ore ear erate earecrte sc bo Sr tac 103
TERIAL. Pe Sneatan ciosc sd anthe le Site Ge ene lr reba baat 105
INF AGRO Del ae oavd:c. cuss «csi snereee oy Geeeeongercl= taleetege ncaa 106
BIE Shane) 0) ee ONE nino gee iron DO ciate 110
lerpopdellidces 0. nau: os ses er eee ee 120
Mepobdella © vias ie ein s+ cei alah estes aon a paige 121
NephielOpSiS) sje. ous eee oe oy sete ee 123
TARA ohare cer Sivas Shae ays SNE an ait Satna 125
Plates and Eplanations ....-..--.eseeseeee eset ec eeeaes 129

Tinley SB koe. 147

STATEMENT

The material, notes and models upon which this report is basd
are stord in the Department of Animal Biology of the University of
Minnesota. All of the material was collected in Minnesota by and
under the direction of the Zoologist of the Geological and Natural His-
tory Survey of Minnesota.

The original plan of the report contemplated a full account of
the habits, gross and minute structure, development and relationships
of the leeches in general and a classification of the leeches of Minne-
sota.

Professor Moore’s report on the material sent to him for identifi-
cation and description was receivd several years ago, but the publica-
tion of it could not be undertaken at that time. Shortly afterward
Dr. Hemingway completed his thesis on Placobdella pediculata. It
was then decided to add this thesis as a unit because it treats of a new.
species parasititc on one’ of our food fishes. The comprehensiv bibliog-
rafy prepard by Hemingway in connection with his work has been
omitted and the general account, the anatomy, histology and embryol-
ogy of leeches, has been reducd to very general terms.

This report on the leeches of Minnesota contains:—1l) A gen-
eral part,—the habits, economic importance, anatomy, development
and relationships of leeches; 2) A special part,—an account of the
anatomy of a new species found parasitic on one of our river
fishes: 3) A systematic part,—a key to and descriptions of the
species collected in Minnesota together with an account of their
habits and distribution, so far as these are known. This part will
enable any one to identify representatives of the species here de-
scribd. Specimens that can not be identified with any of the
species describd in this report may be sent to the Department of
Animal Biology, University of Minnesota, Minneapolis, Minnesota,
for identification. Inquiries will receive prompt attention.

The publication of the report has been delayd for various reasons
that have no vital bearing on the value of the report.

The plates were made by the Bureau of Engraving of Minneapo-
lis.

The printing was done by the Index Press of Minneapolis.

PART I

GENERAL ACCOUNT
¢ OF THE
HABITS AND STRUCTURE OF LEECHES
BY
HENRY F. NACHTRIEB

GENERAL INTRODUCTION

The leeches, also cald blood suckers by people in general
and Hirudinea by the scientist, are distributed all over the world.
They are mentioned in the writings of many of the ancients.
Herodotus, who was born about 4280 B. C. wrote about the leech
under the name “bdella”, which still forms the ending of some of
our scientific names of certain leeches and groups of leeches. Galen,
a Greek physician and author born about 130 A. D., recommended
the use of the leech for bloodletting. Other Greek and Roman,
German, French and English writers wrote about the leech and its
habit of sucking blood, so that in a general way leeches became
quite well known centuries ago. The medicinal leech in particular
became well known thru a great many more or less extended writ-
ings on its anatomy and habits and was brought into almost uni-
versal use by physicians. It was continued in quite general use
until about the middle of the 19th century. Altho this leech in
particular was in such general use and it and others frequently
became objects of scientific study, we did not get a correct concep-
tion of some of the most prominent features of leech structure
until 1900. There is still much to be cleared up concerning the
structure and life history of many of our leeches.

Habits.

Most of the leeches live in fresh water, under stones, leaves
and wood, on water plants, in the mud and ooze on the bottom of
ponds, lakes and streams, and attacht to other animals. A few
live in salt water, a few in moist earth, and a few on land in the
forests of tropical and semi-tropical countries. They can crawl
about after the manner of the “measuring worms”, using their
suckers when thus moving about. Those living in the water are
also good swimmers. They swim by graceful undulations of the
body. Land leeches when dropt into the water usually sink to the
bottom and then crawl out.

Many of the leeches feed on the blood of vertebrates. Some
of the bloodsucking leeches remain attacht to their hosts only long
enough to become gorgd with blood, and some apparently spend

4 THE LEECHES OF MINNESOTA

most of their lifetime attacht to their hosts. The latter are con-
firmd parasites. The former are only temporary parasites, they
living free and independent lives most of the time. Both groups
are well represented in the lakes, ponds and streams of Minnesota.
They are frequently found on turtles, fish, frogs and crayfish and
sometimes on freshwater mussels, birds and mammals. Several
species will attach themselves to man, some, especially when
young, showing a preference for the tender regions between the
tOES.

Other leeches, like the common horse leech found in our lakes,
are scavengers and carnivores. They feed on snails, small clams,
worms, insect larvae, smaller leeches, ded fish, &c. They do not,
as a rule, attach themselves to living animals for the purpose of
sucking blood. When, however, the usual food is scarce some of
them will feed on blood suckt from the animals to which they
may become attacht. These are temporary or occasional parasites.
This group is also represented in all parts of the state. It is fully
as widely distributed as the true bloodsuckers.

Of the twenty one, species collected in Minnesota and de-
scribd in this report eight are true bloodsuckers, four are blood
and flesh eaters, six are flesh eaters and scavengers, and of three
the habits are practically unknown. Of these some species are
found in all parts of the state and others are found only in certain
regions. A species may be very abundant in one locality and
rare in another. Undoubtedly species now reported for only cer-
tain localities. will later on be found in others, and species once
abundant in some localities may now be rare or even absent in
those localities. On the other hand, a species reported rare or
wanting in some locality a few years ago may now be found
abundant there. Their wide distribution is largely due to their
habits. They are distributed or carried from one body of water
to another by the migrating animals to which they became attacht
and in the weeds and mud adhering to these animals, particularly
turtels, birds and mammals. The eggs or very young enclosed in
capsules attacht to water plants and other objects may also be
carried from one place to another by birds and mammals and the
wind.

There are, all told, a few more than one hundred species
generally recognizd today. They are distributed all over the world.

THE LEECHES OF MINNESOTA

un

Economic Importance.

In many places leeches are abundant enough to be of economic
importance. They may be of value in so far as they serve as food
for fishes and birds or in so far as they are scavengers. On the
whole, however, the leeches are rather an injurious group. They
may kill fishes and other animals, particularly the young by bleed-
ing them to death or, indirectly, by devouring the snails, worms,
larvae &c. which constitute the principal food of some fishes. They
are also injurious in so far as they serve as intermediate hosts
for various developmental stages of animals that during some pe-
riod of their lifetime are parasitic on fishes, birds and other animals.
There is still a great deal to be learnd about the life histories of
many of our leeches, their relations to other animals, particularly
their relations to fishes, and their influence on the character of
the fauna in particular bodies of water.

The wounds made on man by the bloodsucking leeches very
rarely produce any serious results. Considerable, sometimes in-
tense, itching of the region immediately around the wound is usu-
ally the only noticeable effect. More serious results are probably
due to infection. When, however, the leeches find their way into
internal passages, they may produce serious disturbances. The
young of the bloodsucking horse leech taken in by horses and
cattle while drinking from ponds or lakes have been known to be-
come attacht to the lining of the farynx and the windpipe and cause
more or less serious disturbances. Fortunately the number of
species that in this way practically become internal parasites is
very small, and the chance of their invading human beings exer-
cising some care is very slight. It may. be well to remember, how-
ever, that it was a small inconspicuous leech, not thicker than a
horse hair, that was the cause of considerable trouble to Napoleon
in Egypt. His soldiers in drinking water direct from thg streams
and lakes and pools took in small leeches which attacht themselves
in the back part of the mouth cavity and caused annoying blood
spitting and difficulty in breathing. The small land leeches so
much dreded in the forests of some countries (South America,
Australia, Japan, Ceylon and others) are not found in Minnesota.
What the introduction and acclimatization of such forms in our
forests would mean may be inferd from the following account taken
from Tennent’s book on Ceylon:—Of all the plagues which beset

6 THE LEECHES OF MINNESOTA

the traveler in the rising grounds of Ceylon, the most detested
are the land leeches (Hemadipsa ceylonica). They are not fre-
quent in the plains, which are too hot and dry for them, but
amongst the rank vegetation in the lower ranges of the hill coun-
try, which is kept damp by frequent showers, they are found in
tormenting profusion. They are terrestrial, never visiting ponds
or streams. In size they are about an inch in length and as fine
as a common knitting needle; but they are capable of distension
till they equal a quill in thickness, and attain a length of nearly
two inches. Their structure is so flexible that they can insinuate
themselves through the meshes of the finest stocking, not only
seizing on the feet and ankles, but ascending to the back and
throat, and fastening on the tenderest parts of the body. In order
to exclude them, the coffee planters, who live among these pests,
are obliged to envelop their legs in “leech-gaiters” made of closely
woven cloth. The natives smear their bodies with oil, tobacco,
ashes, or lemon juice, the latter serving not only to stop the flow
of blood, but also to expedite the healing of the wounds. In movy-
ing, the land leeches have the power of planting one extremity
on the earth and raising the other perpendicularly to watch for
their victim. Such is their vigilance and instinct, that, on the ap-
proach of a passer-by to a spot which they infest, they may be
seen amongst the grass and fallen leaves on the edge of a native
path, poised erect, and prepared for their attack on man and horse.

. Their size is so insignificant, and the wound they make is
so skillfully punctured, that both are generally imperceptible, and
the first intimation of their onslaught is the trickling of the blood,
or a chill feeling of the leech when it begins to hang heavily on
the skin from being distended with its repast. Horses are driven
wild by them, and stamp the ground in fury to shake them from
their fetlocks, to which they hang in bloody tassels. The bare
legs of the palankin bearers and coolies are a favorite resort; and
as their hands are too much engaged to be spared to pull them off,
the leeches hang like bunches of grapes around their ankles.”

One of our species, Macrobdella decora, has been used insted
of the medicinal leech for bloodletting, but since bloodletting thru
the leech is no longer considerd a cure for all ills this species can
hardly be clast with animals beneficial to man.

The medicinal leech in the heyday of bloodletting was culti-
vated in great numbers in France, Hungary, Russia and other

THE LEECHES ‘OF MINNESOTA

N

countries. One American leech farm sold as many as 1000 or more
a day. Today leeches are so seldom used that few young people
have seen a medicinal leech, and most physicians of today do not
know how to apply a leech properly. It is difficult to say how
much leeches are still used because the leech industry has ceasd
to be one of commercial importance. That they are, in comparison
with former days, used very seldom is evident from the fact that
where several thousand were employd fifty years ago there is
scarcely one employd today. It has been estimated that France
used about twenty five million in 1846. About 7 million were used
in the London hospitals in 1863 and five to six million in the
hospitals of Paris. Today one can not find a leech in most of our
hospitals. Naturally the price of the medicinal leech has dropt.
About eighty years ago medicinal leeches were worth $50.00-$75.00
per thousand. About fifty years ago they were worth $20.00-$40.00
per thousand and today they are not worth more than $20.00 per
thousand with a very much restricted market.

Hirudo medicinalis, the medicinal leech, included a number of varieties
that up to about the middle of the nineteenth century were almost univer-
sally used by the medical profession. When full grown and extended this
leech is from eight to twelve inches long and about half an inch wide. The
general or ground color is a dull yellowish brown to gray or greenish gray.
On each side there may be an orange stripe borderd with black and, as a
rule, the dorsal side is markt with six rust-red longitudinal lines spotted with
black. The coloring, however, varies so much that at least sixty-four
varieties basd on these minor differences have been describd. Among
the most prominent of these are the socald German and Hungarian medi-
cinal leeches. The German medicinal leech (H. medicinalis) is markt on
the dorsal side with six longitudinal reddish lines and on the ventral side
with black spots. The ventral side, however, varies from the spotted to
an almost uniformly black coloring. This variety is the common one in
the markets of Germany, France, Denmark, Sweden, Russia, England and
America. The Hungarian variety is markt with only four reddish to brown-
ish lines on the dorsal side and an unspotted olive green on the ventral
side. This variety is found most common in southern and southeastern
Europe.

The medicinal leech (of all varieties) prefers lakes and ponds having
a clay bottom and a rich growth of plants. It swims about actively dur-
ing the daytime and during its earlier vears feeds largely on the blood of
some of the socald coldblooded animals, like turtles and fish. When
mature it feeds on the blood of socald warmblooded vertebrates.

The eggs are enclosd in oval coccoons about an inch long. The
coccoons are deposited in the earth near the shore during June, July and
August. The young come out six to eight weeks after the eggs are laid
and do not become fullgrown until five years later. They are not of any
value for bloodletting until three years old. Under favorable conditions
they may live for more than twenty years.

When bloodletting was an almost universal practis various
means were employd to make gorgd leeches disgorge the blood

CO

THE LEECHES OF MINNESOTA

in their digestive tracts so that they could be stimulated to renewd
sucking on the next patient. Such treatment made-every mature
leech available for repeated operations within a short time. The
practis was fraught with danger for the patients (danger of infec-
tion thru the leech’s mouth) ; but it was a natural result. A leech
gorgd with blood might be satisfied for many months. <A _ study
of its physiology and habits disclosd the way to greatly reduce this
period of uselessness. Accordingly the pleasures of the sucker were
multiplied by depriving him of the fruits of his labor for the financial
benefit of his keeper. It is interesting to note that, as stated in
Vol. II of the Cambridge Natural History, “The former extensive
use of the leech has led to the transfer of its name to the doctor
who employs it, the authors of the sixteenth century constantly
terming a physician a leech; it has been suggested, however, that
the term was applied rather by way of analogy.”

Fortunately for humanity the general practis of bloodletting
by means of Hirudo medicinalis is a practis of the past.

External Characters.

The leeches of Minnesota are easily recognizd by their ex-
ternal features. The most prominent of the external characters
are a distinct sucker at the posterior end of the body and a more
or less evident sucker or sucker-like differentiation around the
mouth. When at rest the leech is elongated, more or less flattend
dorso-ventrally, tapering gradually toward the anterior or mouth
end and more abruptly at the posterior end. A fair conception of
the general leech form can be obtaind from the frontispiece and
plate A. The general outline of the leeches is quite uniform, the
external differences being largely differences in color, color pat-
terns, skin papillae and the arrangement of the annuli. The body
is very muscular and can be much shortend, changd in shape or
tightly rold up. Some species, when not swimming or crawling
about, actively change their outlines, often assuming many odd
shapes in comparatively rapid succession or holding some odd form
for several minutes at a time. This is particularly true of some of the
smaller, leaf-like leeches. When kept in aquaria they will often crawl
up the sides of the aquaria until the anterior end is just below or near
the surface of the water and will then begin a series of remarkable mus-
cular exercises. These changes in form may have some pysiological
significance, such as aiding the circulation of the blood and the lymph

THE LEECHES OF MINNESOTA 9

and thus indirectly hastening excretion. The following outlines, Fig. 1,
represent some of the more striking shapes assumd by one of the

Glossiphonidae.
I

dirt

These striking changes of form have not been observd among the
more elongated, ribbon-like leeches. In these the change of form is

Fig.

practically limited to extension or elongation accompanied with a de-
crease in width and to a contraction or shortening in length accompanied
with an increase in width.

Another characteristic external feature is a more or less evi-
dent annulation of the body. Nearly all leeches appear to be made
up of a series of rings technically cald annuli. Such annulation or
segmentation of the body is quite characteristic of a large group of
worms cald annulata. This group includes a large variety of
marine worms, some freshwater worms, the earthworms and the
leeches.

A careful examination of our common earthworm, also cald
angleworm, will disclose the fact that the internal organization is
also segmented and that this internal segmentation corresponds to
the external annulation. In other words, the annulation seen on
the surface of the body represents a condition of the entire organ-
ization. For example, a ring in the middle region of the body is
separated from the ring in front of it and from the ring behind it
by a thin transverse partition at each end. Between these parti-
tions, that is within the ring, there is a nerve centre and certain
nerve fibers, a pair of excretory organs, muscles and so on. The
same 1s true of the ring in front of this and the ring behind it.
Indeed all the annuli, excepting a few modified ones of the anterior
end and a few modified ones of the posterior end, are quite alike in
their make-up. The earthworm, therefore, may be thought of as
an animal made up of a number of similar rings or segments joind

together end to end in a single row. Each ring or segment in such

10 THE LEECHES OF MINNESOTA

an organism is technically cald a somite or metamere, and the
condition of being thus built up is cald metamerism.

The earthworm presents metamerism in a relatively simple
form. In the leeches, however, the external annulation does not
correspond to the real metamerism. Each true somite or metamere
includes several of the externally evident rings or annuli. Conse-
quently the number of annuli in the leech is always greater than
the number of somites or metameres.

Moreover, there are no evident partitions between the somites
to aid in determining the limits of even a typical somite. But
careful study has disclosd the fact that the nerves have definit
relations to the annuli and that other internal structures present
certain definit relationships, so that we now can determin the
limits of the leech somite quite as definitly as we can those of an
earthworm.

It is now generally accepted that the leech body is composd
of thirty three or thirty four somites. The number of annuli varies
considerably in the different species but the number of somites is
always the same. This is one of the features in which the leeches
differ from the other groups of annulata.

The limits of the somite adopted in this report are not those
current prior to 1900. It is not necessary to give more than a brief
discussion of the limits of the leech somite in this report since any
one interested in the question can find a clear and full presentation
of it in Castle’s paper on “The Metamerism of the Hirudinea” in
Vol. XXV, 1900, of the Proceedings of the American Academy of
Arts and Sciences. This paper was reprinted as No. 108 of the
Contributions from the Zoological Laboratory of the Museum of
Comparative Zoology at Harvard College. Also in Moore’s paper
entitled “A Description of Microbdella biannulata with Especial |
Regard to the Constitution of the Leech Somite”, which appeard
in the Proceedings of the Academy of Natural Sciences of Phila-
delphia of 1900.

The earlier writers recognizd only the annuli, which they num-
berd consecutively from the anterior end back. They located
structures by direct reference to the number of the annulus. In
1862 Gratiolet pointed out that the annuli of the medicinal leech
are not all alike but that they are arrangd in similar groups
(somites) within which are always found certain structures. Later
it was generally admitted that the ganglia (groups of nerve cells

THE LEECHES OF MINNESOTA II

and nerve fibers) are definit internal criteria of the somites. Now
in a leech having three annuli to a typical somite each ganglion
gives off three nerves on each side to certain definit parts of the
somite. Prior to 1900 the annulus carrying the dorsal sense organs
of such a leech was considerd the first annulus of the somite. This
annulus also containd the ganglion. The nerves coming from this
ganglion, however, were distributed to the annuli of two somites.

Castle concluded from his observations that if the ganglion 1s
an important element of a somite it is only natural to expect all of
its nerves to be supplied to that somite, and accordingly he decided
that the anterior or first nerve went to the first or anterior annulus,
the second nerve to the second annulus, which contains the gang-
lion and bears the dorsal sense organs, and the third nerve to the
third or posterior annulus. These limits also brought other inter-
nal structures into more satisfactory relationships and presented
the somite in all details of structure as a complete unit in itself.

Moore had reacht the same conclusion independently.

In the accompanying diagram,
Fig. 2, the somite as determind
by Castle and Moore, and adopted
in this report, is indicated on the
right side and the limits according
to the older writers are indicated
on the left.

Not only does the number of
annuli vary in the different species,
while the number of somites 1s
constant, as has already been
stated, but the number of annul1
in different somites of any given

species varies. The anterior and posterior somites always have a
smaller number of annuli than the somites of the middle region of the
body. The typical number of annuli to a somite of any species is de-
termind by the number in the somites of the middle region of the
body. The annuli of a somite may also be equal or unequal in size.
Frequently some annuli are only partially divided, and in some species
certain annuli are always divided only on the dorsal or ventral side.
With regard to the annulation nearly all of the leeches can be

12 THE LEECHES OF MINNESOTA

placed in two groups, one having three primary annuli and one five
primary annuli in a typical somite.

The differences in the number of annuli and the modifications
of them in the anterior and posterior somites of the leeches of
Minnesota are clearly and fully presented in the systematic portion
of this report. It may be well, however, to note that in all leeches
several of the posterior somites (six or seven) are fusd to form the
attaching sucker and the number of annuli is more or less reduced
in the anterior somites.

More precise and accurate descriptions of the various species
and a more satisfactory identification of each species are made pos-
sible by numbering the somites and annuli of each somite from the
anterior end back. The somites are now generally designated with
the Roman numerals and the annuli with the Arabic. A few ex-
amples will make this clearer than can a detaild description. A
structure or marking on the first annulus of the twelfth somite
would be located thus,—XII al; something on the boundary line
between the first annulus and the second of the same somite, thus,
XII al/a2; and something between the twelfth and the thirteenth,
thus, XIJ/XIII. To indicate the relation of the secondary to the
primary annuli the letters a, b,c, &c are used, a indicating a primary
annultis; b, a secondary annulus and‘c, a tertiary annulus. The fol-
lowing diagram, Fig. 3, illustrates the derivation of a typical somite
of five annuli and a typical somite of six annuli from one of three
annul.

Three annuli to a typi- Five annuli to a typi- Six annuli to a typical
cal somite as in Glos- cal somite as in Ma- somite as in Actinob-
siphonia. crobdella. della.

Fig. 3.

The fellowing diagram, Fig. 4, illustrates how annuli become
divided into two, four or six annuli and how a somite of four or
twelve or fourteen annuli may be derivd from a somite of three
annuli.

THE LEECHES OF MINNESOTA 13

a3

Mvacrobdella
€ 2

Fig. 4.

If c2 and c3 in the above diagram had also been divided, ar would
be represented by eight annuli. The diagram represents the annula-
tion of typical somites of the genera selected excepting in the case of
Macrobdella. The typical somite of Macrobdella is quinquiannulate,
a3 being divided into b5 and b6. The diagram represents somite VIII
of Macrobdella decora.

Figures four and five present as
the system of notation adopted by eA or

ae dz
Professor Moore to indicate the re- b1
lationships of the annuli.

The leeches vary considerably 41 Z

in size. The smallest is about an 3 =

be

eighth of an inch long and the

largest (Macrobdella valdiviana of

Chili) reaches a length of a foot ea

and a half or more and a width of bie

about one inch.’ The smallest Min- qa

nesota species is less than half an ie ae ya
4

inch long and the largest is from
seven to ten inches long and less Co-—=
than an inch wide. be

The color markings are varied, me b ah Clie
simple and irregular in some and S o) | en
definit and regular in others. Some Fig. 5.

14 THE LEECHES OF MINNESOTA
are quite dull in color and some are bright and very attractiv. A few
of the color patterns are shown in the frontispiece and plate A.

In most of the leeches one to five pairs of eyes, appearing as
more or less conspicuous pigment spots, are evident on the dorsal
side of a few of the anterior somites. Special sense organs, cald
sensilla, can be recognizd in most leeches on the dorsal surface
of one of the annuli of most of the somites.

The body has no external appendages, such as antennae or
gills, excepting in a few species, not found in Minnesota; two have
external gills on certain somites. But the body is always coverd
with a thin, tough cuticle and more or less mucous. Some species
can secrete a large quantity of mucous in a very short time.

The openings into the digestiv tract, the mouth and anus, usu-
ally are quite evident at or near the anterior and posterior ends
respectively. In the region of somites XI/XII, on the mid-ventral
line, there are two openings one to five annuli apart. The anterior
of these is the external opening of the male reproductiv organs and
the other is the external opening of the female reproductiv organs.
The excretory organs open to the exterior thru inconspicuous pores
on the ventral side of the somites containing them.

When a leech is cut in two the body appears to be practically
a solid mass of tissue, the only conspicuous cavities being those of
the digestiv tract and some other organs. The digestiv tract and
other internal organs do not appear to lie in a distinct cavity as,
for example, do the intestin and some other organs of the chicken
or the frog. The body wall of the leech can be removd so as to
leave a compact mass of supporting tissue and embedded organs,
the whole presenting the general outline of the intact leech. In
other words, the space between the body wall and internal organs
and between the various organs is fild in with supporting tissue and a
characteristic vascular tissue. Consequently, in order to get a view
of the internal organs, this tissue must be carefully dissected away.

In Plate B are reproduced the fotografs of three successiv
stages of the dissection of one of our large leeches. In figure 1 only
the body wall has been loosend and pind out. The figure shows
that the supporting and vascular tissues so completely fill the space
between the various internal organs that none of the organs are very
evident.

In the second stage of the dissection, shown in figure 2, the

THE LEECHES OF MINNESOTA 15

posterior third of the digestiv tract and the supporting and vascular
tissues of the posterior half of the body have been removd, thus
exposing part of the digestiv tract, part of the ventral nerve cord
and part of the reproductivy and excretory organs.

In the third stage, shown in figure 3, the supporting tissues and all
of the digestiv tract have been remoyd, thus exposing the reproductiv
organs, the excretory organs and the central nervous system.

The longitudinal muscles of the body wall are plainly seen in
each of the three figures.

INTERNAL ANATOMY

Digestive Tract.

The digestiv tract is a more or less highly differentiated tube
extending from one end of the body to the other. In most of the
Minnesota leeches several distinct regions can be easily recognizd
in it. But there is no uniformity in the differentiation nor in the
names applied to the several regions by the various writers.

The Mouth

is on the ventral surface at the anterior end in the center of a more
or less well developt sucker. In one group of leeches, cald the
Gnathobdellidae, it is provided with three “jaws” that radiate from
a common point with an angle of about thirty degrees between the
middle jaw and each of the outer of the trio. The free edge of each
jaw is curvd and coverd with a horny (chitinous) band that is
notcht like a saw. When these jaws are workt back and forth on
the skin of the host by the special muscles attacht to them they cut
a ragged wound in the skin, which bleeds much more freely than
would a single clean cut. The mouth opens into a short portion
cald the

Farynx or Esofagus.

This is a muscular region which by the action of its muscles
can create a strong suction thru the mouth. In one group of leeches,
cald the Rhyncobdellidae, it can be protruded and is often spoken of
as the proboscis. In the true bloodsuckers this region has opening
into it a large number of unicellular glands cald salivary glands.
They are located mainly in the two-or three somites immediately
in front of the anterior reproductiv opening. Hemingway has also
describd a multicellular gland he calls the esofageal gland that
opens into this region thru a cellular duct. For the full account
see page 49. These glands produce a secretion which prevents the
coagulation of the blood suckt from the host. The esofagus opens
into the largest portion of the digestiv tract, cald

18 THE LEECHES OF MINNESOTA

Stomach or Crop.

In the true bloodsuckers this region has from two to fourteen
or more lateral diverticula or pouches technically cald gastric ceca.
As arule there is one pair of these ceca to a somite in the region of
the stomach but in some cases there are two pairs to a somite.
They are side pockets which serve as reservoirs for the ingested
blood. When they are full the leech may leave the host and seek
some secluded place where the digestion of the bountiful meal may
be continued in peace. The blood does not clot in this region owing
to the addition of the secretion from the glands noted above. When
all the blood has been digested the leech will actively seek a host
for a new supply. The adults of some species may store enough
blood in this region to last for several months. The medicinal
leech has been known to make one meal last for more than nine
months. Generally there are no digestiv or gastric ceca in the leeches
which do not suck blood. In this group the digestiv tract is a straight
tube markt into the several regions by differences in size and general
structure. The stomach or crop opens into a narrower portion cald
the

Intestin

In the true bloodsuckers this also may have several pairs of
lateral diverticula, cald intestinal ceca. When the blood enters this
region of the digestiv tract it becomes rapidly changd in color and
composition. This indicates that activ digestion takes place in this
region. A short terminal portion of the intestin is sometimes so
modified that it can be recognizd as a distinct region. When
recognizable it is cald the rectum. The intestin or rectum opens
to the exterior thru a small inconspicuous opening cald the

Anus.

The anus is on the mid-dorsal line usually on or near the
-oundary between the body and the posterior sucker.

The general anatomical features briefly noted above are repre-
sented in figure 4 of plate C and in part in plate A.

Circulatory System.

The blood vascular or circulatory system in general consists of
several longitudinal vessels (dorsal, ventral and lateral), connecting
branches in each somite, vessels to the nefridia and other organs,

THE LEECHES OF MINNESOTA 19

and socald sinuses, some of which, if not all, represent portions of
a true body cavity. Portions of this system have contractile walls.
The blood is kept in circulation by the more or less regular pulsa-
tions of these vessels and the irregular contractions of the very
muscular body.

Respiratory System.

None of the leeches found in Minnesota have any special organs
of respiration. That function is performd almost wholly by the
skin. Two marine genera, Branchellion and Ozobranchus, have gills on
certain somites.

The Excretory System.

The excretory system consists of a series of more or less highly
differentiated tubes cald nefridia. Each somite, excepting a few at
the anterior end and a few at the posterior end, contains a pair of
these nefridia, one on each side. Typically the nefridium consists of
a funnel-shapt “mouth” that communicates with a small space rep-
resenting the body cavity, a glandular portion well supplied with
blood-vessels and a non-glandular, bladder-like reservoir which
opens to the exterior thru a small pore (the nefridiopore) on the
ventral side of the body. When a living leech is wipd dry on the
ventral side and is then carefully comprest laterally, small drops of
the secretion of the comprest nefridia may be made to appear at
the nefridiopore and make evident the position of the pore.

The Nervous System.

The central nervous system is essentially a series of paird
ganglia (collections of nerve cells and nerve fibers) connected by
a double nerve. In this chain we recognize a pair of small, some-
what pearshapt ganglia near the mouth on the dorsal side of the
farynx or esofagus. They are connected with each other at their
larger ends and are cald the brain or supra-esofageal ganglia. The
smaller end of each ganglion is continued into a nerve that passes
around the farynx to meet the one from the other side beneath the
farynx on the midventral line in a paird ganglion often cald the sub-
esofageal ganglion.

From the sub-esofageal ganglion the double nerve extends along
the midventral line of the body wall, immediately under the di-
gestive tract, to the posterior end, connecting a series of ganglia,

20 THE LEECHES OF MINNESOTA

one ganglion for each somite. This chain of ganglia and connecting
nerve fibers are collectively cald the ventral nerve cord. From each
ganglion three pairs of lateral nerves radiate out to the various
parts of the somite. One pair of these nerves always goes to certain
sense organs of the somite and the others go to other definit
regions and organs of the somite.

For a more detaild account of the anatomy of the nervous sys-
tem see Hemingway’s account of the anatomy of the nervous system
of Placobdella pediculata, page 40.

Reproductiv System.

The leeches are hermafroditic. That is, both the male and the
female reproductiv organs are present in each individual. But the
two sets of organs are so related in the leech that the eggs of one
individual are fertilizd by the spermatozoa of another.

The male reproductiv organs consist of a series of pairs of
spermaries or testes close to the nefridia in certain somites. The
number varies from five to eleven pairs in the different species. The
series on each side is connected by a common duct, cald the vas
deferens, which opens into a muscular tube in the neighborhood of
somite XI. The terminal portion of the common duct of the two
vasa deferentia is sometimes cald the penis. It can be protruded
thru the male reproductiv pore on the mid-ventral line near to or
on somite XII. The position is constant for a given species but
varies in different species.

The essential female organs consist of only a single pair of
cvaries. The ovaries usually lie in somite XI and the female re-
productiv opening is on the mid-ventral line one to five annuli be-
hind the male opening. For a detaild account of the essential and
~ accessory female organs in one species see Hemingway’s account
of Placobdella pediculata, pages 47 to 49.

Specific anatomical differences are noted in Part III of this re-
port.

In some species fertilization may be accomplisht in a peculiar
way. The spermatozoa are collected in small packets, cald sperma-
tofores. These spermatofores are attacht to any part of the body
of another leech and the spermatozoa escape thru the body wall of
the leech into the underlying connective tissue and thence work
their way to the ova near the uterus, where fertilization takes place.
In others fertilization takes place in the uterus (or in capsules con-

THE LEECHES OF MINNESOTA 21

taining ova, spermatozoa and some albuminous material) by sper-
matozoa introduced into the uterus directly thru the external open-
ing.

Some leeches, like Nephelis, lay a few eggs at a time in small
tough capsules that the leech attaches to the submergd parts of
water plants, stones &c. Others, like Hemopis, enclose a few eggs
in egg-shapt capsules or coccoons that may be half an inch or more
in length. These coccoons are deposited in masses of decaying
vegetation, such as the submergd portions of muskrat houses and
the accumulation of ded roots, leaves and water plants near the
shore or on the bottom of the lakes. Others, like Placobdella
rugosa, carry the eggs and young attacht to the ventral surface of
the body until the young are able to move about actively and find a
host for a meal of blood. In these cases the eggs are laid in small
spherical clusters, each mass surrounded by a delicate membrane of
a mucous-like substance secreted by skin glands. A number of
such groups of eggs are somewhat loosely held together and are
attacht to the ventral surface of the parent by a substance similar
to the membrane around each spherical mass of eggs. When thus
burdend with eggs or young the leech does not travel about very
much but stays in some protected place and by undulatory move-
ments of the body keeps the collection of eggs or young well aerated
until the young are able to shift for themselves. If the egg masses
become dislodgd the parent will make efforts to collect them and
again attach them to her body. Several Placobdella parasiticas with
young in various stages of development are shown in Plate A.

The development and anatomy of the leeches in general and
certain special structures of two or three annulata that appear to’be
on the border-line between the leeches and other groups of annulata
indicate that the leeches are more closely related to the group of
earthworms than to any other group of the annulata.

> | - Vor Ae
_ % ’ ; ' P : 7
i ee vi : c i . 7 a) 2a ye SiS '.*
ry : 7 7 1. 7
‘ r) 7 7 5 -
. :
‘ dis Sead int toe Creer > a
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“ 5 cA n . 7
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aery he 4 h, BY aA ; = : iy ly :
Parco erie mame UN
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ae ORLY Bie egy ae vn Vie ea fe ‘ Rts on +, io rily ue ; z
b4 : vy y oa ‘ 7!
PV re roe he Pr a Le 7 7 “i for fet
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: nee airy ar a | A as :.8's ..
sans | i a ee Rowe |||) ele wel 7 :
et ot Me ee m oe :
ve ths FAs F i TF. Tee, Q), sige? “ij f - _ $3 vi :
‘ J r Ps a @ sf a
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i ij ie hae 13) 9 a eae) ee Pat, uk | ¥ }
> A . ’ i]
Aso r Lee. / ay Pais is : 7 Lae
Saar - oh Oy ane ae ye cy er CT nie ,
Me ‘Wishoet Vs Dea Sm ea TS |
Hl - } A hy i. ? ' : ~~
La m4 ES ee alee om! 7 as j
7 hia a0 Baan 4 or i Pee oe Bh eo ry ""
: higaers ia bag icky Pas on ae Sapa |? RTS Sacia : P ia
er whi j any oe Peet” ay we al : ~ - ii ry a
ee eae! ES A ae es
ae Pee ia Ge LIBS and evs ee AU al (eae Se
- ibe hc Mii A ee wy, : i!
; Padi! Arte, bit} ald Ua teat it i Ae eke tp te ae at
- f ie 4 ; : cd ir a : 7 -
7 A my a) uy ‘ a jm wey ist ee zh a | ¢ ; JAY
On ee 7 re | a fel a ;
Sc AS tk! RE dS Fe Ne Gs Lan ae

Lt 7 ra Py 7
a) rr (‘7 iy 4 Tr man)

PLATES A AND B
AND

EXPLANATIONS

PART I

Explanation of Plate A

Reproductions of fotografs of living leeches.

Several of the upper group show the color patterns of some of
the Glossiphonidae. The six figures to the right of the group
show young leeches in different stages of development attacht
to the ventral surface of the parents.

The lower group of figures shows the gastric and intestinal ceca
more or less fild with blood. The delicate edge of the leech
body is not evident in all cases.

The species represented are Placobdella parasitica and P. rugosa.

Plate A

Explanation of Plate B

Reproduction of fotografs of Heemopis grandis in three stages

of dissection,

Fig. 1. Represents the leech with the body wall cut along the

mid-dorsal line and pind out on each side.

Fig. 2. Represents the same leech with the supporting and vas-
cular tissue of the posterior half and all of the in-
testin removd. A small portion of the dorsal wall of
that part of the digestiv tract shown is cut away.

Represents the same leech with all of the digestiv tract
and surrounding supporting and vascular tissue re-

—

af

me
ae
&

movd. The “brain”, ventral nerve cord, reproductiy
and excretory organs are easily recognizd.
The logitudinal muscles of the body wall are evident in all the
figures.

Plate B

SS ARt

©

paneer

ParRT II

THE ANATOMY
OF

PLACOBDELLA PEDICULATA

BY
ERNEST E. HEMMINGWAY

INTRODUCTION

In the summer of 1899, while at Lake Pepin superintending the
zoological work of the Geological and Natural History Survey of
Minnesota, Professor Nachtrieb found that some of the sheepshead
(Aplodinotus grunniens) which were being seined from the lake in
large numbers by the local fishermen, had a large parasitic leech
fastened to the isthmus or shoulder under the gill cover. Three of
these leeches were collected at that time, with portions of the fish,
showing the place and manner of attachment. One of these speci-
mens was later sent to Professor J. Percy Moore who found it to be
a new species of Placobdella and named it P. pediculata. All the
specimens originally collected were adults, gorged with blood, and
greatly modified in form from the usual Placobdella types by their
close parasitic habit; so that, in some parts, annulation and many
other external features had been entirely obliterated. It was seen
at once that to determine these features, younger and better pre-
served material must be obtained, so during the first part of Septem-
ber 1903, I spent several days with the fishermen around the head
of Lake Pepin examining fish for these leeches. During this time
I examined many hundreds of fish and succeeded in obtaining three
small specimens, none of which were over a centimetre in length.

Methods.

The leeches were removed from their hosts as soon as found
and placed in carbonated water (I used the ordinary bottled “pop”
for this purpose) in which they soon became fully extended and
stupefied. After they had become perfectly quiet (in five to ten
minutes) they were transferred from the carbonated water to Gil-
son’s mercuro-nitric mixture, in which they were left for an hour,
and then put into 80% alcohol and treated with iodine in the usual
way. This method left all well extended and in excellent condition
for study. One was stained in bulk in Mayer’s Paracarmine, im-
bedded in paraffin, cut in transverse series 20/1000 mm. thick, and
mounted without further staining. The second was stained in bulk
in Mayer’s Paracarmine, imbedded in paraffin, cut in sagittal series
5/1000 mm. thick, and counterstained with Lyons blue before

iS)

THE LEECHES OF MINNESOTA

os)

mounting. The third was cleared in cedar oil and examined as a
transparent object. Both external and internal features, as far as
they could be made out, were drawn with the camera lucida. This
specimen was then imbedded in paraffin, cut in transverse series
5/1000 mm. thick and stained with Ehrlich-Biondi stain. The ner-
vous system, (Figs. 17 to 22.), reproductive system, (Figs. 11 to
14), and the oesophageal gland, were worked out by the Born Re-
construction Method from series three, and the wax models thus
made were checked up with similar models made from sagittal
series two. Wax models made from these two series were found
to differ only in minor details, due to slight anatomical variations
and distortions which one would expect to find in any two individu-
als of the same species.

While the method which I have used is essentially the Born
method, I have modified it in several ways. My drawings for this
purpose were all made with a soft Faber pencil, on unsized paper,
from the third series noted above. But instead of drawing every
section, only alternate sections were drawn, and in some cases only
every fourth section was drawn, the sections between being used
to show the relations of parts which had changed too much to have
their relations perfectly clear in the drawn sections. The result
attained is the same as though the series had been cut two or four
times as thick, with the added advantage that one is able to trace
out minute changes which would not appear in the thicker series.
The thickness of the wax plate was made to correspond with the
magnification and the distance between the sections as by Born.
For the models of the central nervous system, I took alternate sec-
tions and drew them with a magnification of 400 diameters, so the
wax plates required were 4 mm. thick.

In making the wax plates I used a method which is quite dif-
ferent from that of Born, and one which I think is in many ways
superior. I first found by mathematical calculation the amount of
melted wax which it would take to produce a plate 1 mm. thick in
pans of a convenient size, and then procured a ladle which, when
filled, would hold exactly that amount. I then got ready a large dish
of melted wax and a quantity of hot water. The pans were, one
by one, filled nearly full of hot water and, according to the thickness
of the plate wanted, one, two, three or four of the ladles full of
hot wax were poured upon the surface of the water and spread over
it evenly with a hot spatula. A little extra wax was always added

THE LEECHES OF MINNESOTA

ios)
Ww

so that the plates would be slightly thicker than they were finally
wanted. As the wax plate congealed, it was cut free from the
edges of the pan to prevent its cracking; and when the plates were
sufficiently hard, they were lifted out by one edge and laid upon
some flat surface until cold, then they were cut into the sizes re-
quired. By having several pans of the required size, a large number
of plates can be made in a short time and kept on hand ready for use.

Two metal strips of the required thickness, as used by Born,
were then placed a short distance apart on a piece of plate-glass.
Between these strips was laid a sheet of tissue paper, and on this
the wax plate of the right size and thickness; and on top of the wax
plate the sheet of paper with the camera-lucida drawing was placed,
drawing side up. The surface was then brushed over with a liberal
amount of turpentine, and a hot roller, long enough for both ends
to rest upon the metal strips was passed over it. The roller which I
used was of hollow brass, filled with hot water, which was easily
kept at the proper temperature by means of a Bunsen burner. As
the temperature of the roller was always slightly above the melting
point of the wax, the superfluous wax was pressed out at the edges
leaving the plate of the exact thickness required. The drawings
were then cut out, superimposed, and the edges trimmed off in the
usual manner.

PLACOBDELLA PEDICULATA n. sp.
Habits.

This leech appears to be a true fish parasite and is found in the
gill chamber of the common sheepshead, Aplodinotus grunniens,
with the posterior sucker deeply imbedded in the side of the isthmus.
In the case of young leeches which have not been long attached, the
hole made by the posterior sucker is comparatively shallow, be-
ing a mere external depression in the inflamed tissue which sur-
rounds it. As the attachment continues the inflamed tissues of the
fish grow up like a collar and close in around the leech’s body in
front of the sucker. This closing up of the inflamed collar presses
upon the body of the leech, narrows it to a mere peduncle, and in-
cidentally crowds the sucker down into the tissues of the fish so
that in time this depression will reach into the underlying mus-
cles to a depth of half an inch or more, and have an opening of
about a quarter (or less) of an inch in diameter. The bottom of the

34 THE LEECHES OF MINNESOTA

depression has a much larger diameter. A look at Plate C will
help toward a clear conception.

Pl. C, Fig. 5, shows the holes in the isthmus of a fish from
which the leeches have been removed, and Fig. 6 represents a
longitudinal section of one of these holes. The surrounding tis-
sue of the fish rolls up to form an inflamed collar about the attenuat-
ed peduncle of the leech. These leeches are capable of becoming
ereatly contracted and when one is disturbed it draws back until it
appears as a mere brownish pyriform knob which entirely covers
the place of attachment. This burying of the posterior segments in
the tissues of the host has brought about an interesting structural
change so that we find the anal opening shifted forward to a posi-'
tion between somites XXIII and XXIV instead of between somites
XXVII and XXVIII as in other members of this genus. It is no-
ticeable that, while the young leeches whose posterior portions are
not yet deeply imbedded, have the characteristic position of the
anus, XXIII/XXIV, the outline of the posterior part of the body
is still a regular curve (Fig. 4), showing none of the pedicular
characteristics so pronounced in the older individuals. The pos-
terior sucker, however, is very strongly developed even in those not
more than a centimetre long.

Practically nothing is known of this leech apart from its host,
but it seems possible that a part of its existence may be spent else-
where. During September 1903, I examined several thousand fish
of this species from Lake Pepin and found only three isolated
leeches, each about a centimetre in length. The posterior sucker,
while imbedded in the tissue, was not sunk in deeply and so had not
produced the characteristic peduncle. They were evidently young
ones which had recently attached themselves to their hosts and were
gradually sinking the posterior sucker into the flesh. As full grown
specimens, deeply attached, were found in the same locality during
August of 1899, at least some of the adults must remain with their
hosts during the summer and probably throughout the year.

THE LEECHES- OF MINNESOTA 35
DESCRIPTION.. *

Plate C, Figs. 1, 2, 3 and 4.

Like Placobdella parasitica and P. rugosa this is a species of large
size, thongh not quite equaling the largest examples of the forms
mentioned. It is more than usually contractile and therefore. dif-
ficult to preserve in suitable condition for study. The very char-
acteristic pyriform outline and strongly convex dorsum are evident
from the figures, but the most striking peculiarity is the attenua-
tion of the posterior somites to form a narrow pedicle just in front
of the caudal sucker, which consequently stands out freely exposed
behind the body in a most characteristic manner. The oral sucker
has the same structure as in P. parasitica,

No trace of cutaneous papillae can be detected, the skin being
perfectly smooth, and the segmental sensillae and scattered sense
organs are very indistinct. Eyes are very difficult to detect in the
mature animals, but appear as small pigment masses at III/IV in
the young. The annulation is essentially like that of P. parasitica
excepting the caudal peduncle and the generally simpler structure
of the corresponding somites of P. parasitica.

Somites I and II contain each but a single annulus. Somites
III and IV are bi-annulate and V is bi-annulate dorsally but ven-
trally the furrow fades away medially; VI is tri-annulate above,
but the furrow al/a2 is incomplete below. Somites VII to XXIV
are tri-annulate but the furrow al/a2 is incomplete medially on the
ventral side of both VII and VIII and in most of the succeeding
somites is less marked than either a2/a3 or the inter-segmental fur-
rows. In the anterior somites, and, to a less degree, in the posterior,
a3 is slightly longer than al or a2. The annulation of the post-anal
somites, constituting the caudal peduncle, is irregular and somewhat
puzzling on the older specimens, but is fairly distinct on the young-
er ones. Somite XXIV, which immediately succeeds the anus, is
tir-annulate. Somites XXV, XXVI and XXVIII are all bi-annulate,

*This description is based upon both young, and large, mature speci-
mens gorged with blood. In view of unavoidable delay in the publication
of Professor Nachtrieb’s projected report on the Leeches of Minnesota,
Piofessor Moore kindly consented to the free use of his description em-
bodied in the systematic portion of this report. I have retained the specific
name suggested by Moore, though his description, being based upon a
single large, gorged and much contracted specimen was of necessity some-
what incomplete.

The original description was published in The American Naturalist,
Vol. XLII, August, 1908.

36 THE LEECHES OF MINNESOTA

but al of Somite XXV is partially divided and al of both XXVI
and XX VII is larger than a2. Neither annulus of XXVII is com-
plete, al reaching only to the sides of the body and a2 not so far.
The disc is composed of somites XXVIII to XXXIV. Fig. 4 rep-
resents the arrangement of the furrows in a young animal. Somite
XXIV is the last segment of the body proper and its posterior
boundary forms in contracted specimens a fold which envelopes the
contiguous portion of the narrowed peduncle. The latter continues
to narrow to the sucker, to the middle portion of which it is strongly
attached for rather more than the posterior half. The posterior
sucker is large, circular and directed strongly ventrad. The nephrid-
iopores are in the sensory annuli of somites VIII to XI, and XIII to
XXIII and are placed similarly to those of P. parasitica.

The mouth is very small and situated far forward near the
anterior rim of the sucker in somite II. As in related species the
proboscis is slender, and the crop provided with seven pairs of large
caeca reaching nearly to the margins of the body. The caeca,
however, are less deeply and finely divided than in P. parasitica,
each of the first six pairs exhibiting only two or three rather short
lobes. The intestine reaches to the posterior part of somite XXIV
or even beyond and then bends abruptly forward toward the
dorsum as an extremely narrow rectum reaching to the minute anus
situated at XXITI/X XIV. The forward curvature of the rectum and
the anterior position of the anus are unique features in the
family. The salivary glands are widely scattered through the an-
terior two thirds of the body. On either side of the oesophagus, in
somites X and XI, lie a pair of compact oesophageal glands which
join the oesophagus by a short duct in somite XI.

The reproductive organs are essentially similar to P. parasitica.
The male and female external orifices are situated at XI/XII and
XIa2/a3 respectively. Six pairs of testes are crowded between the
bases of the gastric caeca. The large sperm sack and ejaculatory
duct of the vas deferens form a compact snarl in somite XII in the
immediate neighborhood of the atrium.

THE ANATOMY OF THE CENTRAL NERVOUS SYSTEM
OF LEECHES.

A brief Historical Sketch.

The first writer to describe in any way the central nervous sys-
tem of the leech was Poupart who, in 1697, spoke of a knotted

THE LERCHES JOR MINNESOTA: 37

nerve cord which extends from the mouth to the posterior end. With
the exception of Haller who claimed that the leech had no nervous
system, no further mention is to be found until 1791 when it was
again described by Bibiena. In 1795 Mangili gave the correct
number of ventral ganglia with a good illustration of the nerve
cord. The supra-oesophageal ganglion, however, seems not to have
been known to him. In 1809 Cuvier described correctly the oe-
sophageal collar and its connection with the sub-oesophageal mass;
he gave the whole number of ganglia as twenty-three but did not
distinguish the posterior ganglion from the others. Like other
early writers he discribed the cord as single. Spix, in 1813, was the
first to discover the double nature of the nerve cord. He also
gave the correct number of nerves arising from the ventral ganglia,
but found only two pairs for the anterior ganglion; the supra-
oesophageal ganglion was not known to him.

Up to this time the surrounding ventral vessel had been consid-
ered as part of the nerve cord, but Johnson, in 1816, described it as
a ventral vessel. Bojanus, in his Anatomy of the Leeches, in 1817,
speaks of the entire independence of the nerve cord and the blood
system; and Joh. Miller, ’28, speaks of the ventral vessel as the
“eigene schwartze Haut des Markstranges.” The monograph of
Moquin-Tandon, ’27, added very little that was new to the knowl-
edge of the nervous system. He found that, toward either end of
the nerve cord, the ganglia became crowded nearer together, that
the two end ganglia were larger than the others, and that the caudal
ganglion was made up of seven or nine ventral ganglia. He con-
cluded from this that the caudal ganglion was not yet completely
formed. Weber, ’28, declared the last ganglion to be a second brain
made up of seven knotted swellings. He writes, “Ich zahle wie
Bojanus, das Gehirn mit gerechnet, 22 Ganglien des Knoten
stranges. Aber des im Saugnapfe des Schwanzes vorhandenen
Ganglienstranges finde ich aus 7 verschmolzenen Knoten bestehend
und also einem zweiten Gehirne ahnlich .... Die 2 Faden des
Ganglienstranges welche die Knoten desselben unter einander
verbinden, verlaufen an den dem Saugnapfe des Schwanzes nahe
liegenden Knoten getrennt von einander. An den 7 verschmolzenen
Knoten dagegen, welche in der Mittelline des Saugnapfes des
Schwanzes befindlich sind, vereinigen sie sich. Jeden von den
7 verschmolzenen Knoten hat wbrigens Aehnlichkeit mit einem
einzelnen Knoten des Ganglienstranges.”

38 THE LEECHES OF MINNESOTA

3randt, 33, found three small ganglia lying behind the jaws
and a nerve running along the digestive tract which he declared to
be the sympathetic nervous system.

Up to this time practically all the work done on the nervous
system had been by surface dissection; only the external appearance,
after the outer tissues had been removed, being considered. The
work on the inner structure then began and we find Ehrenberg,
Valentine, Helmholtz, Hannover, Will Bruch, Leydig, Quatrefages,
Faivre, and Walter contributing to the microscopic anatomy of
leeches:

After Newport had discovered, between the two connecting
commissures in some of the arthropods, a third smaller commissure,
Faivre, 56, described a similar nerve, since known as the Nerve of
Faivre, for Hirudo medicinalis. According to his account, this
third commissure ran from one ganglion to the next, between the
two principal commissures, in many places fusing with these
larger cords. He made the number of nerves springing from the
supraoesophageal mass to be four, from the sub-oesophageal three,
and from the posterior at least seven. Faivre also described the
Leydig’s cells which had been described by Leydig in 1849. He
found five ganglia in the head which he considered to be sympathet-
ic ganglia, but found no nerve connecting them with each other,
or with the central nervous system, or with the visceral nerve.

Leydig, ’49, was the first to understand the follicular nature
of the ganglia and was also the first to describe the cells (Leydig’s
cells) lying between the ganglionic nerves. In “Vom Bau des
Thiereschen Korpers” °64, he describes the head ganglia and the
sympatheticus, and thinks it probable that the sympathetic system
is joined with the central nervous system either through direct
connection with the brain, or through the Leydig’s cells, or perhaps
by means of the central nerve of Faivre.

Herman, ’75, described the sympathetic system of Hirudo medi-
cimalis and found both the head ganglia and the gastric nerve, but
did not find any connection between them. He wrote, ‘‘auch ich habe
nie einen Zusammenhang des Sympatheticus mit den betreffenden
Ganglien oder andern Abschnitten der Bauchganglienkette gefun-
den, und halte, nach ihrem ausseren und inneren Bau dieses acces-
sorischen Gebildes, theils ftir integrirende Bestandtheile des Gehirns,
theils stelle ich sie in das Gebiet des IV. Gehirnnerven.” When we
examine his figure, however, we find that he has figured ten pairs of

THE LEECHES OF MINNESOTA 39

nerves coming from the brain and that these include several
branches of the anterior sympathetic nerve, so his 1V brain nerve
is in reality a branch of the anterior sympathetic nerve coming from
the oesophageal commissure at the base of nerve II. From his
description it would seem that he found both parts of the sympathe-
tic system attached to the brain at the base of the second somatic
nerve although that was not his interpretation. Herman also divid-
ed the anterior nerve packet of the ventral ganglia into “vordere
ventrale” and “mittlere ventrale”’ making the number of packets
seven instead of six,

Gratiolet, ’62, pointed out that the annulation had a definite
relation to the segmentation and made of each ventral ganglion the
brain, situated in the first annulus, of one of the elementary zooids
which go to make up the leech body. Toward the ends the zooids
are more closely crowded together and so the individual annulation
becomes indistinct or lost. Whitrnan, 84, made segmentation de-
pend wholly upon the internal organization, annulation being no
criterion to follow. Born, ’84, based the number of somites upon
the number of ganglia, but did not count the number of ganglia
correctly. SaintLoup, ’85, would go a step further than Gratiolet
and make the leech a colony of annulates bearing a relation to each
other similar to the relation of the trematodes which go to make
up the Tenia series. Apathy, ’88, saw no ground for such a
colony theory, but found definite septa separating the body somites
(the presence of which had been denied by Born, ’84) and a por-
tion of the coelomic cavity and a ganglion in each somite.

Whitman, ‘92, proved that in Clepsine, the whole body is made
up of a series of true segments, each represented by one of the
separate or fused ganglia of the nerve cord. He says, “The meta-
meres of Clepsine show in all the important details of their external
features and internal organization that they represent morpho-
logically individuals, which have undergone internal integration by
which their individualities have been merged in one complex in-
dividuality. Each metamere has its nerve-center composed of like
elements, its nerves essentially identical in number, origin and dis-
tribution ; and its external sense organs similar in structure, position
and function.” Whitman was the first investigator to work out the
relation of annulation to segmentation, in the anterior and posterior
regions, the morphological value of the supra-oesophageal ganglion,
and the relations between ganglia and somites. He, however, made

40 THE LEECHES;j;OF MINNESOTA

the sensory annulus the first annulus of the body somite so that his
neuromere did not correspond with the body metamere.

Bristol, “98, worked out the metamerism similarly for Nephelis,
and, in addition, investigated the sympathetic system. He found the
sympathetic system connecting with the central nervous system at
the collar near nerve roots I and II and forming a nerve circle in
front of the collar, with six capsules containing nerve cells, and a
plexus over the wall of the alimentary tract. In the work of Bristol
as well as the work of Whitman, the sensory annulus is taken as the
first ring of the somite. Castle, 00, and Moore, ’00, working by
entirely independent methods, and without knowledge of each
other’s work, came to the same conclusion with respect to the an-
nulation of the somite, viz—that the sensory annulus is not the
first annulus of the somite, but the middle one in both the three ring
and five ring types. This brings the neuromere and the body somite
into harmony and seems to be supported by all conditions. Liva-
now, ‘03, has worked out the innervation of the body somite for
both the three and the five ringed types much more elaborately than
they have heretofore been studied, and endorses the view of Castle
and Moore.

In this review of the work done upon the anatomy of the central
nervous system of the leech I have omitted such work as Apathy,
97, and Havet, 00, and Retzius, 91, which are of a purely histo-
logical or cytological character. Nor have I attempted to review
the publications of all those who have done valuable work upon the
outer form of the nervous system. Much of this work has been of
a substantiating character and while these writers have added many
minor details which are of value, they have made no decided ad-
vance beyond their predecessors. Some of the works referred to I
have been unable to procure and so have been obliged to depend
upon the quotations of other authors who were more fortunate than
I and who have been able to review them first hand.

Central Nervous System of Placobdella pediculata.
(PRE, Bigs 17 tor.)

The central nervous system may be divided into a cephalic por-
tion, a trunk portion, and a caudal portion. The anterior part con-
sists of the supra-oesophageal mass, the oesophageal collar, and the
sub-oesophageal mass. The trunk portion consists of a ventral

THE LEECHES OF MINNESOTA 41

nerve chain of ganglia, each connected with the ganglion preceding
and with the ganglion following by two large lateral commissures
and a third, smaller, central commissure, the so called Nerve of
Faivre. The caudal portion is the posterior ganglionic mass, situ-
ated in the anterior side of the posterior sucker.

The Ventral Nerve Chain.

The ventral nerve chain is made up of twenty-one somatic
ganglia with their connecting commissures. Throughout the middle
portion of the body these ganglia are about equal distances apart,
but toward the ends they are crowded closer together. The last
three ganglia of the chain are especially close together but are
separated from the posterior ganglion by a much longer space, prob-
ably due to the pressure exerted around this region by the tissues
of the host. The first, central ganglion is closely approximated to
the sub-oesophageal mass and the fifth and sixth (ganglia XI and
XII) are closer together than the others near them.

The typical ventral ganglion, which may be taken as the unit
of structure of the central nervous system, consists primarily of a
fibrous portion and a cellular portion. The fibrous portion is made
up largely of nerve fibres entering from the connecting commissures,
the somatic nerves, and the six cell packets. Fibres continuing
through the ganglion from the lateral commissures form two lateral
fibre tracts and the fibres crossing from one side to the other form
two transverse fibre tracts, one before and one behind the center of
the ganglion. Among the fibres are to be found occasional leuco-
cytes and two large glia cells (mediane Sternzellen of Apathy, ’97).
These glia cells are medially situated beneath the two transverse
fibre tracts, one anterior and one posterior to the centre of the
ganglion. In a few cases I have found the anterior cell divided so
that there were three median glia cells in the ganglion instead of
two. Herman, ’75, described these cells as “mediane Ganglienzel-
len”, Retzius, 91, as “kolossale Ganglionzellen” and ‘“Nervenzellen”’.
Apathy, ’97, was the first to describe them unmistakably as glia
cells.

The cellular portion of the ganglion consists of six cell packets,
each containing nerve and glia cells, and surrounded by a regular
capsule from which emerge the nerve fibres of the enclosed nerve
cells. These packets occupy a definite position in each ventral
ganglion, two being on each side, lateral to the central fibrous mass,

42 THE LEECHES OF MINNESOTA

and two being on the ventral side directly underneath the median
glia cells. The packets are usually ellipsoid in shape, but may be
variously distorted by constricting muscle and nerve fibres, so that
they are, in some cases, completely divided.

The cell packets each contain a number of unipolar nerve cells
which send their fibres directly into the fibrous portion of the
ganglion, and one or more large glia cells (“Stirnzellen” Apathy,
97). Each side packet contains one of these cells, sometimes cen-
trally located, but often lying near the outer margin of the packet.
This condition holds good throughout the nerve cord. The glia
cells are much larger than the ganglion cells, and as the nucleus
stains much more deeply with the ordinary chromatin stains, they
can easily be distinguished from the other cells of the packet. In
each ventral packet a pair of these glia cells are found lying side
by side near the distal end of the packet. This double condition
of the glia cells of the ventral packets is not unique for P. pediculata,
but is found in at least one other Placobdella, viz. P. parasitica,
however, the glia cells in the side packets are also double.

Irom each side of the fibrous portion of the ganglion, midway
between the two lateral packets, arise the three branches of the
somatic nerve; these pass backward and laterally, usually passing
under the posterior lateral packet, and then to the various annuli
of the somite in which the ganglion is situated.

The connecting commissures consist of two large cylindrical
fibrous trunks, the lateral commissures, and a smaller central Nerve
of Faivre, (Plate E. Fav. n.) which takes its origin in the ganglion
between the two lateral commissures, or from one of these com-
missures near the ganglion. This central commissure may continue
its course independently between successive ganglia, occupying a
position between the lateral commissures; or it may, in places,
anastomose with one of the lateral commissures. A lateral commis-
sure, instead of always remaining a single trunk, frequently divides
into two branches which, after a short distance, again unite into
one cylindrical cord. In some cases all three commissures are fused,
for a short distance, into one solid cord. Lying along the central
axis of the commissure are two or more large spindle-shaped inter-
commissural cells. The normal number of these cells seems to be
two, one lying near each end of the commissure; but in many
cases one or both of these cells have divided, forming three, four,
and, in some cases, up to eight cells scattered along the whole

THE LEECHES OF MINNESOTA

Ns
Ge

length of the commissure. Lavinow, ’03, finds this same double
condition of the intercommissural cells in Protoclepsis tessellata,
and thinks there is some relation between the doubling of these
cells and the binucleate condition of the muscle cells. As nearly all
the muscle cells in P. pediculata are also binucleate, the same rela-
tion would seem to exist here. Appearances would seem to indicate
that amitotic division is the prevailing method for all these nuclei.
Lavinow, 92, would make the binucleate condition of the muscle
cells and the presence of two intercommissural cells, characteristic
for a new genus, Protoclepsis, which would separate it from Hem-
iclepsis, on the one hand, and the Glossiphonidae (Glossifhonia,
Placobdella and Haementeria) on the other. The possession of both
of these characteristics by at least two species of Placobdella, viz.
P. pediculata, and P. parasitica, would indicate that there is a much
closer relationship between the genera Protoclepsis and Placobdella
than Lavinow imagined.

The Anterior Ganglionic Mass.
(PIE. Figs..17, 18 andi19:)

In P. pediculata there are no sharply defined supra- and sub-
oesophageal ganglia. The cell packets belonging to the suboesoph-
ageal ganglion of such leeches as C. hollensis Whitman extend in
this species far around toward the dorsal side of the oesophagus,
while the packets of the supra-oesophageal ganglion extend ventrad
beyond the median line, so that some packets belonging to the
former are much farther dorsal than some packets belonging to
the latter. The anterior ganglionic mass consists, as Whitman,
92, has shown for C. hollensis, of six closely joined neuromeres,
each having the parts equivalent to one of the ganglia of the ventral
chain. Lhe commissures are here shortened almost to complete dis-
appearance, leaving the ganglia so closely approximated that only
a small canal, across which runs the central Nerve of Faivre, re-
mains between the adjacent fibre masses. Above each packet is to
be found the usual central glia cell.

The eight ventral packets of neuromeres III, IV, V, and VI are
arranged in a median ventral row, so closely crowded together that
each body of the row, with the exception of the two at the ends
which are about as long as wide, is two or three times as wide as
long. The ventral packets of somite II are somewhat smaller and

44 THE LEECHES OF MINNESOTA

are arranged side by side at the head of this row. The side packets
are not so regularly arranged. The fourteen side packets belonging
to somites VI, V, IV, and the posterior half of III, are arranged
in two irregular rows at either side of the fibrous mass. The
anterior packets of somites IV and V are shoved closer together
and dorsad, while the posterior packet of somite IV is crowded
ventrad. The lateral packets of somite II and the anterior lateral
packet of somite III lie along the posterior side of the oesophageal
collar, which bends sharply dorsad from the suboesophageal portion,
and extends in a wide loop around the digestive tract. An interest-
ing variation is to be noticed in the left posterior lateral packet of
somite II which has been completely divided, retaining only a com-
mon point of attachment. Partial or complete division of cell
packets is rather common in different parts of the nervous system
and is evidently the result of the mechanical pressure of organs
which may be in contact with them. In some cases it is probably
brought about by constricting muscle fibres, while in others it is
clearly the result of a nerve having been crowded against the
packet until it has pinched it completely in two.

The six packets of cells of somite I are situated on the anterior
side of the oesophageal collar, the ventral packets having been
pushed to the extreme dorsal side of the loop, while the lateral
packets lie along the sides of the collar below the outer margins of
these dorsal packets. The posterior pair of lateral packets of somite
I are about as far ventral with respect to the oesophagus as the
anterior pair of somite II are dorsal. There is, then, in this species,
no distinct supraoesophageal ganglion, but a suboesophageal mass
and an oesophageal collar, around which are distributed ganglionic
packets belonging to the first three ganglia. The equivalent, how-
ever, of the supra-oesophageal ganglion is to be found here in the
part anterior to the collar. The oesophageal commissures which go
to form the collar are not the homologues of the lateral commissures
of the ventral chain, but are made up of the ganglionic fibre masses
of several ganglia. This state of affairs is exactly what we should
expect to find if several ventral ganglia had been crawded together
until the ventral commissures were practically eliminated, and then
the oesophagus had been forced between the anterior two, pushing
the median ventral bodies of these two ganglia with their crossing
fibre masses, to the extreme dorsal and ventral sides. The position
of the ganglionic parts would seem to indicate that there had been

THE EE CHES“OE MINNESOTA 45

a concentration of ganglia around a small mouth followed by a
stretching of parts as the collar slipped back over the larger
pharynx, as supposed by Whitman, ’92.

In ganglion VI we have an arrangement similar to the typical
ventral ganglion in all respects except that the packets are more
closely pressed together and the somatic nerves arise nearly op-
posite the anterior bodies. Ganglion V is similar to ganglion VI
except that the central trunk of the somatic nerves (V2) takes a
dorsal course, passing across the inner anterior margin of the
anterior lateral packet of ganglion V, then passing between the
lateral packets of ganglion II and over the lateral dorsal margin of
the oesophageal collar. Ganglion IV is similar to ganglion VI ex-
cept that the somatic nerve of each side is composed of two trunks
instead of three. Ganglion III differs from ganglion IV in that
the anterior lateral packet is attached to the posterior side of the
oesophageal collar directly above the posterior packet. The nerve
of this somite takes its origin just in front of the anterior lateral
packet.

Ganglion II departs widely from the typical somatic ganglion,
the ventral packets being side by side at the anterior ventral side
of the oesophageal collar and the lateral packets being far dorsal on
the posterior side of the collar. The nerves of this somite have each
been reduced to one trunk which takes its origin from the anterior
side of the oesophageal collar just outside and above the ventral
packet of that side. From the inside of the collar at the base of
this nerve, arises the stomatogastric nerve (Plate E, st.n.) which
arches toward the median line and then turns caudad along the
oesophagus. This nerve arises just where we should expect the
anterior “motor” trunk of the somatic nerve, but the part supplied
is very different from that which we should expect the anterior
branch of the somatic nerve to supply. The similarity of this nerve
to the vagus nerve of vertebrates, both in origin and termination,
is rather striking.

Ganglion I is very similar to ganglion II, but the ventral
packets have been pushed to the dorsal side of the collar and the
lateral packets have migrated to the anterior side. The nerve of
somite I has only one trunk and arises from the inside of the collar
a short distance above nerve II, Just outside the origin of this
nerve lies the posterior lateral packet. In the collar, just above the

base of each nerve of somite I, there is a large nucleus which evi-

46 THE LEECHES OF MINNESOTA

dently belongs to the central glia cell of this somite. It will also
be remembered that in the ventral ganglia each lateral packet con-
tains only one large glia cell, while the ventral packets each have
two. A further examination of the packets of somite II reveals
the fact that the four packets at the sides of the collar likewise have
only one glia cell, while the two dorsal packets each contain two.
This must be considered as still farther and more conclusive evi-
dence of the homology of the supraoesophageal ganglion and the
ganglia of the ventral chain, and it also makes the two central
packets at the dorsal side of the collar homologous with the ventral
packets of the ventral ganglia. No trace of the Nerve of Faivre,
which is present in the openings between all other ganglia, could be
found here. It seems to have completely disappeared.

The Posterior Ganglionic Mass.
(PI>E, Pigs. 20,2) and? 22°)

Throughout the posterior portion of the body of the leech, the
nerve cord runs nearly parallel to the ventral surface; but when the
commissures enter the posterior sucker and become united in the
posterior ganglionic mass, they bend sharply dorsad making nearly
a right angle with the line of the ventral cord. The posterior mass
shows unmistakable evidence of being composed of seven somatic
ganglia which have been crowded together in a manner similar to
those of the anterior mass. Each of the original ganglia retains
its six cell packets, two central glia cells, and its pair of somatic
nerves. Each nerve, however, has only two trunks instead of three
as in the ganglia of the ventral chain.

In the anterior ganglion of this mass, neuromere XXVIII, the
packets have retained more nearly their typical arrangement than
in any of the succeeding ganglia. The two ventral packets occupy
practically the same position as in the ganglia of the ventral chain,
but the side packets have been crowded together so that the anterior
one comes to lie nearly above the posterior and the somatic nerves
arise behind the posterior lateral packets. In all succeeding ganglia
the ventral packets lie side by side, making two rather irregular
rows, and the ventral packets of somite XXXIV are attached close
to the bases of the somatic nerves of that segment. In somites
XXIX, XXX, XXXI, XXXII and XXXII, the posterior lateral
packets are attached by a narrow neck close above the bases of the

THE LEECHES OF MINNESOTA 47

somatic nerves, while the distal end of the packet lies some distance
out on the anterior (dorsal) side of the nerve. The anterior lateral
packets occupy a position antero-dorsal to the posterior packets
against which they are closely crowded. The left posterior lateral
packet of ganglion XXIX has been completely divided by the nerve
so that half comes to lie on either side of it; both parts, however,
enter the common fibre tract at the same place (PI. E, Pig At)sabhe
lateral packets of somite XXXIV have been crowded entirely away
from their lateral position so that they have come to occupy a central
position, close together upon the dorsal side of the ganglion. Along
the median line of the fibrous portion of the mass is to be seen the line
of openings which are the remains of the commissural openings. They
are six in number, separating the seven ganglia of the mass, and in the
center of each is to be seen the very short piece of the Nerve of Faivre.
At either side of these openings are the usual central glia cells.

Eyes.

There is a single pair of eyes situated near together at III/IV.
The pigment cup and visual cells are deeply seated and the sensory
cells from the sensillae (sensilla III) are correspondingly long. I
find nothing in my sections of young leeches to suggest the doubling
of the eye as found by Whitman, ’92, for Clepsine hollensis. There
are a few pigment cells below sensilla II and a similar group below
sensilla IV, but there is no arrangement of them which would indi-
cate an optic cup containing visual cells.

Reproductive Organs.
(PI. C, Figs. 3 and 4, and PI. D, Figs. 11 to 16.)

The male genital pore, (¢, Fig. 3, Pl. C and Fig. 11, Pl. D)
lies in a mid-ventral position at XI/XII. The female genital pore,
(@, Fig. 3, Pl. C and Fig. 11 and Fig. 16, Pl. D) lies two rings be-
hind the male opening at XII 2a/3a. There are six pairs of testes,
(Doig. 4)-Pl C and Figs. 11 and 12; Pl. D) situated inter-segmen-
tally from XIII/XIV to XVIII/XIX. They are nearly spherical
in shape and lie in the spaces between the crop diverticula, the
last pair lying behind and median to the last pair of diverticula.
Owing to the pressure of the other organs they are somewhat flat-
tened antero-posteriorly with the exception of the last pair which
are larger than the others, and, as they have no diverticulum be-
hind them, are considerably elongated.

48 THE LEECHES OF MINNESOTA

From each testis there arises, usually from the inner ventral
margin, a vas deferens, (vd. Figs. 4, Pl. C, 11 and 12, Pl. D). The
place of origin of the vas deferens with respect to the testis is not
constant as it may sometimes arise even from the outer margin, as
in the fifth testis of the left side, (Figs. 4 and 11). After leaving
the testis the vas deferens arches dorsally and outward, finally unit-
ing with the vas deferens communis (vdc) for that side. The vas
deferens communis takes its origin in the vas deferens of the sixth
testis, running dorsad and cephalad, dipping slightly to receive the
vas deferens from each testis. After passing into somite XIII it
bends vetrad and medially. In somite XII it turns sharply dorsad,
then cephalad and ventrad; then comes a more or less complete
loop which joins the larger vesicula seminalis, (vs, Figs. 11, 12 and
13, Pl. D). The vesicula seminalis arches dorsad, cephalad and
ventrad, then again turning cephalad becomes continuous with the
smaller ductus ejaculatorius, (d, Figs. 11, 12, 13 and 14, Pl. D) at
about XI/XII. The ductus ejaculatorius winds about in somite
XI with several loops and at the front of the somite becomes
greatly enlarged into the end portion(s) which Whitman, “91, has
shown, in Clepsine plana, to secrete the spermatophore. This en-
larged portion arches dorsad, caudad, and ventrad, and then turns
to the median line where it joins the similar duct from the opposite
side in a common atrium (a, Fig. 15 and Figs. 13 and 14, Pl. D).
This common cavity opens, by a narrow passage with thick muscu-
lar walls, into the enlarged bursa (b) which connects with the out-
side by means of the male genital pore.

The course of the genital duct is very nearly constant in differ-
ent individuals and is often an important factor in determining
species. Barrows, 93, referring to this fact, said, “It is found that
in two species of Aulostoma . . . the relation between the nerve
cord and the sperm duct (vas deferens) is constant:—the right
sperm duct always passing under the nerve cord in one species and
to the left in the other. In some cases where the external specific
differences are so small as to require the closest examination for
their detection the positional relation of the ducts of the repro-
ductive organs to the nerve cord will set aside the difficulty.”

The histology of the male duct corresponds on the whole with
C. plana (Whitman, 91) and the different parts probably perform
the same functions; the enlarged portion of the duct (vs) serving
as a reservoir for mature spermatozoa, and the enlarged terminal

THE LEECHES OF MINNESOTA 49

portion secreting the spermatophore. This must, however, remain
a matter of conjecture until more is learned concerning its habits,
as neither spermatophores nor other methods of reproduction have
been observed. The atrium (a, Fig. 15, Pl. D) is lined dorsally
with long columnar epithelium which is continuous with the glan-
dular epithelium of the vas deferens communis. This epithelium be-
comes very much shorter at the base of the atrium, losing its glan-
dular appearance and in the narrow opening joins the cuboidal,
ectodermal epithelium which lines the bursa. (b, Fig, 15, Pl. D.)
The female reproductive organs consist of the ovaries, (ov,
Figs. 4, Pl. C, 11 and 12, Pl. D) and a pair of simple sacks lying
nearly horizontally in segments XIII and XIV between the two
sperm ducts. Near the anterior end each ovary sends a branch
ventrally which, turning toward the median line, unites with the
branch from the opposite side and opens on the surface by means
of the female pore, (2, Fig. 3, Pl. C and Figs. 11 and 16, Pl. D). At
its anterior end the ovary forms a caecum which extends forward
in front of the female pore nearly to the atrium of the male ducts.
It is entirely probable that the ovaries would be much larger in
older specimens taken when the eggs were approaching maturity.

Glands.

Oesophageal and Salivary Glands.

The oesophageal glands, (oeg. Figs. 4, 9 and 10, Pl. C) are
paired glands lying in somites X and XI which empty by a short
duct into either side of the oesophagus in somite XI. The lumen
of the glands is large and open and sends off numerous short pockets
or alveoli. The whole gland is lined with a columnar epithelium
of striated gland cells. The striation in these cells is very pro-
nounced and extends from the free end of the cell clear through to
the wall resting on the basement membrane. Between these cells
are wedged, here and there, smaller supporting cells (sce. Fig. 10,
Pl. C) containing small, darkly staining nuclei. In the short duct
which joins the oesophagus, the gland-cells gradually become
smaller, at the same time losing their striations, and pass over into
the regular oesophageal epithelium,

These glands are not to be confused with the salivary glands
(“Halsdrtissen” Apathy, 98) which are in all cases unicellular,
and are, in this species, widely distributed among the tissues

50 THE LEECHES OF MINNESOTA

through the anterior two thirds of the body. The ducts from these
cells form two bundles, situated dorsally, inside the longitudinal
muscles, at either side of the median line. These bundles of ducts
enter the proboscis near its base and continue forward among the
muscle bands, finally emerging near its tip.

Although I have hunted through all of the available literature,
I have been unable to find any description of glands similar to what
I have above called oesophageal glands. The only reference I can
find to such glands are in Whitman, "91, for Clepsine plana and
Siegel, 03, for Placobdella catenigra M. T. Whitman’s Fig. 5, PI.
XIV, in the Journal of Morphology, Vol. IV, shows two obscure
bodies in a position which are designated as “oeg.” The explana-
tion of this figure gives ‘‘oeg.—=oesophageal pair of glands.” 1
have looked: through his description carefully and find no other
reference to them. Siegel figures similar glands for Placobdella
catenigra and makes them the temporary abiding place of the
sporocites of Haemogregerina stepanovi, from which they are trans-
ferred to the turtle. No details of structure are shown in his figures
and no description of the glands is given in the text. Castle, ’00,
neither figures nor describes them for Placobdella parasitica al-
though sections of this species in my collection show similar glands
to be present.

Posterior Sucker Glands.

Beginning with about somite XX and:throughout the remain-
ing posterior portion are to be found numerous posterior sucker
elands which, in general, bear a close resemblance to the salivary
glands but stain much more deeply with Ehrlich-Biondi stain. The
ducts from these glands are very small, and form several bundles
among the tissues, finally opening upon the posterior sucker.

Nephridia.

The nephridia are fifteen in number and are found in all the
somites from VIII to XXIII with the exception of somite XII in
which the generative ducts are large and the nephridia are lacking.
The nephridopores are latero-ventral and are to be found a little
anterior to the center of the sensory annulus. The nephridial
funnels open into the coelomic cavity latero-dorsally (n.f. Fig. 7,
Pl. C). The funnel, (Fig. 8, Pl. C), consists of three ciliated crown

THE-LEECHES OF MINNESOTA

un
Ll

cells (“Kronenzellen’, Graf, 99) and a short stile cell which opens
into the larger receptaculum.

In conclusion I wish to acknowledge my great indebtedness to
Professor Nachtrieb, under whose direction this work was done,
for his kindly assistance and many valuable suggestions; and to the
Alumni Association of the University of Minnesota for fellowship
privileges enjoyed during the year 1903-4.

PLATES C TO E
AND

EXPLANATIONS

Parr iI

General Legends of Plates C, D and E.

ae aa aot ot SA UDILIIM- Pelle this etc. ine Fig. 4 ok

ATMs Melaiele ee aus. Plate C refer to the so-

Shs Renee bursa. mites but in all other

(CO ee OC crown cell. figures they refer to so-

COG ante. coelom. matic nerves.

Geapmn at tcresis ductus ejaculatorius. 1, 2, 3, etc.=ganglion packets
Ejaculatory gland of of somatic ganglia I, II, I],
the sperm duct. etc. respectively.

Gree mi ravaeiens eve

PAG eye viake Nerve of Faivre.

Dewan c atte gland cell.

i heer eee intestine.

Thies eee st muscle.

ALLO Ie nie enephridial funnel.

DCA OE aE cecal portion of ovary.

Boe es ee ,oesophagus.

Sots Saks oesophageal collar.

Geeu en «nee oesophageal gland.

GE Yano as ovary

Ove eee co oviduct.

PLOW Gear r: proboscis.

COG ee ae receptaculum.

eas estes enlarged portion of vas
deferens communis.

S@ai4 = at supporting cell.

SiGe raietensh ome = stile cell.

Stn......--- stomato-gastric nerve.

pss aerate he trey testis

(Saari Ae second branch of nerve V.

(0 Saeane SNC Spee vas deferens.

WC een cic vas deferens communis.

iA SR home vesicula seminalis.

ROR aetna an wandering cell.

NS ea eee male genital pore.

So hte female genital pore.

PLATE CG:

Placobdella pediculata.

Figs. 1, 2 and 3. Lateral, dorsal and ventral view respectively.

Fig.

4. Dorsal view of a young specimem, showing the constitution
of the somites and the positions of the organs.

Portion of the isthmus of Aplodinotus grunniens, showing
holes produced by the posterior sucker of P. pediculata.

on

. 6. Longitudinal section of one of the holes shown in figure 5.
. 7. Transverse section thru somite XIX, showing the position

of the nephridial funnel on the left side.
A nephridial funnel.

oo

g. 9. Drawing of a model of the esophageal glands and the posi-

tion of the esophagus into which they empty.

. 10. Section thru three alveoli of the esophageal gland, showing

the striated gland cells. From a specimen hardened in Gil-
son’s mercuro-nitric mixture and stained in paracarmine
and Lyons blue.

Plate C

ig. 11.

PLATE CD,

Placobdella pediculata

Lateral view of the generative organs. Reproduction of a
photograph of a wax model. The ovary and convoluted
portion of the male duct were reconstructed by the Born
method, while the testes and vas deferens commune im-
mediately above them were modeled after careful meas-
urements and then attached to the anterior part.

The same as figure 11, dorsal view.

. Lateral view of the anterior portion of the male duct.

Frontal view of the anterior portion of the male ducts.

5. Sagittal section of the male genital pore, showing the posi-

tion of the atrium (a) and the bursa (b).

. Section thru the female genital pore.

Plate D

PLATE. 4.

Placobdella peliculata

Figs. 17, 18 and 19. Right lateral, ventral and left lateral view re-
spectively of the anterior portion of the central nervous
system with a portion of the proboscis. Reproductions
of photographs of a wax model made by the Born recon-
struction method.

Figs. 20, 21 and 22. Posterior, lateral and frontal view respectively
of the posterior ganglionic mass. Photographs of a wax
model made by the Born reconstruction method.

Plate E

Parr i]

CLASSIFICATION

OF THE

LEECHES OF MINNESOTA

BY
J. Percy Moore

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INTRODUCTION

That the lake region of Wisconsin, Minnesota and Manitoba
abounds in leeches of large size and great variety has long been
known, and has been commented upon frequently by visitors to
that well-watered area. The very first recognizable descriptions
of North American leeches, published by Thomas Say in 1824, were
based upon examples observed in the territory about Lake Vermil-
lion in Minnesota. Since that time a number of additional species
have been described from localities about the western end of Lake
Superior.

The richness of the leech fauna of Minnesota is fully estab-
lished by the splendid collections, gathered by the State Zoological
Survey under the direction of Professor Henry F. Nachtrieb, which
form the chief basis of this report. The entire State is not repre-
sented in the collection, most of which came from the northern
section, chiefly from Lake Vermillion, Leech Lake, Mille Lacs and
their environs. Yet it includes twenty species—a number probably
greater than could be found in an area of equal size elsewhere in
the United States, or, so far as has been recorded, anywhere else in
fresh water. Leeches generally have a wide geographical distribu-
tion and the presence of most of these species in other parts of the
state is to be expected, as many of them range through the entire
northern tier of states or even beyond, several are circumpolar, and
ene, Glossiphonia stagnalis, is almost cosmopolitan. The occur-
rence of a considerable number of the species in the southern por-
tion of Minnesota has been ascertained through material received
from other sources, the most important being a collection sent to
me by Prof. Henry L. Osborn, which, indeed, adds one species,
Placobdella hollensis, not represented in the Survey collections.

The plan of this report is to give descriptions, which are some-
thing of a compromise between the technical and popular, of the
salient features of the entire organization of each species, omitting
altogether those minutiae which require more than a simple micro-
scope or ordinary methods of dissection for their verification.
Fuller descriptions of many of the species will be found in a paper
by Castle, Some North American Fresh-water Rhynchobdellidae,

66 THE LEECHES OF MINNESOTA

in the Bulletin of the Museum of Comparative Zoology, Vol..
XXXVI, (1900) pp. 16 to 64, and one by Moore, The Hirudinea of
Illinois, in the Bulletin of the Illinois State Laboratory of Natural
History, Vol. V (1901) pp. 479-547. The literature lists included
in these two papers will enable one to ascertain the principal papers
in which North American Hirudinea have been discussed.

Characteristic features in the anatomy or exterior have been
figured for all of the species, in most cases from Minnesota repre-
sentatives, but new species or those which have not been figured
previously are treated in greater detail.

Of the biological relations of leeches to other animals much
remains to be learned and this field affords a rich opportunity for
exact observation. Likewise the breeding and other habits of many
species are unknown or known only imperfectly. The remarks on
this side of the subject which follow the descriptions are based on
observations made chiefly in the vicinity of Philadelphia.

The drawings of the frontispiece are colored from living ex-
amples taken, with the exception of Hemopis grandis, near Phila-
delphia.

KEY TO THE SPECIES

OF

MINNESOTA LEECHES

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KEY TO THE SPECIES DESCRIBED IN THIS PAPER

The bold-faced numbers refer to the page.

I. Mouth a small pore-like opening in the disk of the anterior
sucker, through which a muscular pharyngeal proboscis may
be protruded.

A. Complete somites formed of three annuli. ;
a. Genital orifices separated by a single annulus; eyes one
pair, distinct.
b. A dark brown cuticular plate and underlying gland
on the dorsum of somite VIII.
1. Body capable of great extension; color pale—
pink, gray or brownish.
Glossiphonia stagnalis, 77
bb. No nuchal plate or gland in the adult.
.2. Body very. slender, elongated and little flat-
‘tened; very transparent owing to the nearly
complete absence of pigment; no cutaneous
papillae. Glossiphonia nepheloidea, 76
3. Body relatively broad and flat: more or less
heavily pigmented with brown arranged in
linear pattern, annulus a2 marked by white
spots usually arranged in transverse rows:
three longitudinal series of conspicuous black
papillae. Glossiphonia fusca, 80
aa. Genital orifices separated by two annuli; eyes in sev-
eral pairs.
4. Three pairs of eyes; gastric ceca six or seven
pairs; a pair of dark longitudinal lines both
above and below.
Glossiphonia complanata, 82
9. Four pairs of sub-equal eyes, all simple; gastric
ceeca nine pairs. Hemiclepsis occidentalis, 96

6. One pair of compound eyes followed by three
or more pairs of much smaller simple eyes;
gastric caca seven pairs.

Plocabdello hollensis, 94

70 THE LEECHES OF MINNESOTA

aaa. Genital orifices separated by two annuli; a single pair

of compound eyes; gastric ca&ca, seven pairs,
branched.

b. Somites I to V much widened to form a distinct

head. ;

7.. Somites I and II biannulate; the dorsum marked

by three strong papillated keels; gastric ceca
much branched. Placobdella montifera, 88
bb. Anterior somites not especially widened.
c. Posterior sucker very free and supported ona
slender peduncle; anus at XXIII/XXIV;
gastric czeca little branched.

8. Body rather high, very contractile; dorsal papil-

lae wanting. Placobdella pediculata, 90
cc. Posterior sucker not supported on a specially
slender peduncle; anus at XX VII/XX VIII;
gastric ceca much branched.

9. Body very much depressed; dorsal papille few,
low and smooth; integuments rather opaque.

Placobdella parasitica, 84

10. Body very much depressed; dorsal papille
numerous, rough and usually high; integu-
ments translucent. Placobdella rugosa, 86

AA. Complete somites composed of more than three annulii.

11. Complete somites consisting of six unequal
annuli; posterior sucker very large and pro-
vided with a marginal circle of contractile
papille; eyes one pair contiguous in middle
line. Actinobdella inequiannulata, 99

12. Complete somites consisting of twelve or four-
teen approximately equal annuli; body divid-
ed into two regions; posterior sucker without
marginal papillae; eyes widely separated on
posterior part of head.

Piscicola punctata, 103

Mouth large, the sucker appearing as its bounding lips; the

pharynx not forming a protrusible proboscis.

A. Eyes five pairs, arranged in a regular arch on somites II to
VI; genital ducts with complex copulatory apparatus;
testes strictly paired, their number moderate; at least
one pair of gastric czeca present.

IT:

THE EEECHES* OF MINNESOTA Fil

a. Jaws prominent, bearing many small teeth arranged in
one series; accessory copulatory glands present and
opening in. pores behind the female genital orifice.

13. Teeth about sixty-five in each jaw; genital
pores separated by five annuli; the dorsum
marked with median red and marginal black
spots, both metameric.

Macrobdella decora, 106
aa. rene prominent, bearing a few coarse teeth arranged
in paired series; no accessory copulatory glands.

14. Teeth twelve to sixteen pairs on each jaw; the

primary annuli VIIa3 and VIIIar enlarged,

but only partially divided into secondary

annuli; color variable but marked more or

less thickly with mnon-metameric black

blotches. Hezmopis marmoratis, 110

15. Teeth twenty to twenty-five on each jaw; the

secondary annuli VIIb5 and 66 and VIIIbr

and b2 completely formed; color nearly uni-

form, usually with a median dorsal dark
stripe and few or no blotches.

Hemopis lateralis, 113

aaa. Jaws absent or rudimentary ; no teeth; no accessory

copulatory glands.

16. Male genital orifice at XI b5/b6; the female at
XIIb5/b6; color pattern consisting in part
of close or distant blotches of dark pigment
ventral ground color lighter than dorsal.

Hemopis grandis, oe

17. Male and female genital orifices constantly a
the middle of X16 and XII b6 respectively ;
a few distant dorsal blotches or none; no
ventral blotches, ventral ground color not
paler, usually darker than dorsal, the rufous
or orange marginal stripe conspicuous.

Hzmopis plumbeus, 115

AA. Eyes three or four pairs, not arranged ina regular arch,
two pairs situated on somite IV: genital ducts rela-

tively simple, without complex copulatory apparatus;

testes numerous, not regularly paired; no gastric czeca.

>

N

te

THE LEECHES ‘OF MINNESODTA

a. Annulus b6 not obviously enlarged and subdivided.

18. Eyes three pairs; male orifice at XI1b2/a2, fe-
male at XIIb5/b6; atrial horns simply
curved and vas deferens reaching forward
to the level of ganglion XI.

Erpobdella punctata, 121
aa. Annulus b6 obviously enlarged and subdivided.

19. Eyes four pairs; male orifices at XIIb2/a2, fe-
male at XII 05/b6; atrial horns spirally
turned, vas deferens reaching forward to the
level of ganglion XI.

Nephelopsis obscura, 123

20. Eyes four pairs; male orifice at XII Dr/a2 or
occassionally XII a2/b5, the female at XIII
br/b2
ens reaching forward to ganglion XI.

Dina parva, 125

JI

atrial horns simply curved, vas defer-

21. Eyes three or four pairs; male orifice at XII
b2/a2, female at XII 05/b6; atrial horns
simply curved, vas deferens not reaching
anterior to atrium. Dina fervida, 127

DESCRIPTIONS
OF

FAMILIES, GENERA AND SPECIES

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DESCRIPTIONS OF FAMILIES, GENERA
AND SPECIES

Family Glossiphonide.

Leeches of medium or small size; generally rather short, broad
and much flattened, rarely slender and elongated. No distinct clitel-
lum. Caudal sucker usually large and flat; oral sucker rather small
and, except in a few cases, scarcely expanded. Complete somites
of middle region usually of three rings, rarely of 2;.0 or Oy Eyes
1-4 pairs, situated in a longitudinal row close to the median line;
the first pair often compound, the others simple. Dorsum often
studded with cutaneous papillae in addition to metameric sensillae.
Mouth a small pore in the oral sucker. Pharynx a slender, pro-
trusible proboscis without jaws or teeth. Salivary glands present.
Stomach with from one to ten pairs of lateral, simple or branched
ceca. Intestine with four pairs of ceca. Genital orifices separated
by one to four rings, the @ in somite XII and the ¢ in XII or be-
tween XI and XII. Testes sacs usually six, rarely nine pairs; sperm
ducts divided into a very slender vas deferens and a large epididimis
and ductus ejaculatorius, the latter of which opens into a small
median atrium without a penis. Ovisacs a pair of slender con-
yoluted tubules opening together at the female orifice without a
vagina. Fertilization by means of horny spermatophores attaches
to the integument from which the spermatozoa penetrate the, tis-
sues to the ovisacs. Eggs and young borne on the ventral surface
of the parent. Strictly fresh water. Tortoise and snail leeches,
which feed on snails, small worms, etc. or suck the blood of tor-
toises, frogs or fishes, rarely fixed parasites of the latter. Creepers,
mostly poor swimmers.

Genus Glossiphonia Johnston.

Moderately depressed or elongated and nearly terete. Eves
1-3 pairs, all simple. Cutaneous papillae few or none, never strictly
median. Pharyngeal salivary glands diffuse; eastric caeca 1-7 pairs,
simple or slightly branched. Sperm ducts forming a pair of long,
open loops extending through several segments. Chiefly free-living
or attached to invertebrates. |

76 THE LEECHES OF MINNESOTA

Glossiphonia nepheloidea (Graf).
(Plate I, fig. 2)

Clepsine nepheloidea Graf (1899).
Glossiphonia elongata Castle (1900).

Description—This species, which may be called the worm
leech, is readily distinguished from any other member of its family
belonging to this fauna by its slender, elongate, and sub-terete form.
Slightly smaller and much narrower than G. stagnalis its great
power of extension permits full grown individuals to exceed that
species in length. Both the head and caudal sucker are very small
and weak, and the axis of the latter nearly coincides with the
axis of the body. A single pair of widely separated eyes show their
faintly pigmented cups within the anterior part of somite IV. The
skin is smooth and lacks integumental papille altogether; the muchal
gland and plate are also lacking in the adult.

For the most part the annuli are very distinct, regular, smoothly
rounded and simple, but the furrows of the head region are mostly
faint and usually require special preparation to make them visible.
Somites I and II are united into a single annulus or are separated
only by a faint furrow; III, IV, and V are biannulate, the first an-
nulus being the larger in each case; VI to XXIV, inclusive, are
triannulate, and XXV, XXVI and XXVII each uniannulate but
distinct. e

The relatively large mouth is located in somite III. In correla-
tion with the narrowness of the body the stomach is a nearly simple
Straight tube bearing the last pair of reflexed ceca only, and even
these are shorter than in allied species. The salivary glands are
small and of the diffuse type.

As is the condition in many of the smaller species of Glossi-
phonia the genital orifices are separated by only one annulus, the
male being in the furrow XII ar/a2, the female XII a2/a3. There
are six pairs of testes occupying the customary positions, and the
vas deferens is folded into a long post-atrial loop, the terminal limb
of which is an enlarged sperm sac. The longitudinal musculature is
weak and diffuse.

The body of the species, particularly in its anterior part,
is remarkable for its transparency and is almost totally devoid of
superficial pigment. The walls of the stomach and intestine exhibit

more or less of a yellow or pale orange color which is the prevailing
tint of the posterior region of the body.

THE LEECHES OF MINNESOTA 77

Habits—Glossiphonia nepheloidea is by no means an abundant
leech and has been until recently generally overlooked, a result
no doubt in large part due to its inconspicuous coloring and se-
clusive habits rather than its scarcity. Only four specimens, all
taken from Lake Pepin by means of a pump, represent the species
in the Minnesota collections. Whitman, Graf and Castle have found
it only in ponds in Massachusetts. In my experiences it occurs
much more numerously in running water among plants, particularly
along the muddy flats exposed at low water along the Delaware
River, associating with G. stagnalis, G. complanata and sometimes
other species.

In appearance and movements it is much more worm-like than
any other species of Glossiphonia. Its weak suckers and deficient
musculature ill fit it for active creeping and, being incapable of
swimming and of a manifestly sluggish disposition, it moves about
but little and chiefly in the very unleechlike manner of crawling
through the ooze. When exposed in its place of concealment it
writhes and twists in a peculiarly helpless fashion, often for a long
time not even attempting to attach the suckers and never exhibit-
ing that decision of movement and promptitude to seek conceal-
ment which is shown by G. stagnalis. Its means of protection con-
sist largely in the very copious mucous secretion which envelopes
the body when irritated.

Although, like G. stagnalis, this leech will feed on snails and
worms and even suck blood when the opportunity offers, it is es-
sentially a scavenger and feeds largely on the substance of dead ani-
mals and on ooze.

Glossiphonia stagnalis (Linn.) Johnston.
(Plate I. fig. 1.)

Hirudo bioculata Bergmann (
Hirudo stagnalis Linnaeus (1
Clepsine modesta Verrill (1872)

Helobdella stagnalis Blanchard (1896)

Description—Glossiphonia stagnalis is a small leech some-
what larger and decidedly stouter than G. nepheloidea. Large
individuals may reach a length of an inch when fully extended and
in that state would be fully twice the width of a G. nepheloidea of
the same length. When contracted to one-half that length, which
is about the ordinary resting condition, they would be about three

1
Wh

78 THE, LEECHES OF MINNESOTA

times the width of G. nepheloidea and much more flattened, but
still decidedly convex above. The head is small but moderately
distinct, less elongated and more strongly annulated than in G.
nepheloidea. The caudal sucker is well developed, strongly directed
ventrad, and but little exposed posteriorly; its axis ordinarily at
about right angles to the body axis. While only one pair, situated
as in G. nepheloidea, the eyes are much more conspicuous owing to
the greater amount of their pigment. A conspicuous feature is the
more or less deep brown chitinoid plate and underlying gland situ-
ated on the dorsum of VIII az and a2.

There are no distinct integumental papillae though the surface
may be somewhat roughened with scattered sense organs. The
metameric sensillae are inconspicuous as in G. nepheloidea.

The annulation is distinct throughout, especially at the caudal
end, where the annuli are angulated at the margins. Somites I and
II are usually completely united in the short prostomium; III is
uniannulate or occassionally faintly subdivided; IV and V are bian-
nulate, the latter more completely and sometimes showing indica-
tions on the dorsum of the furrow az/a2; VI to XXIV are triannu-
late, and XXV and XXVI biannulate, the latter occassionally being
united with XX VII, which is commonly represented by a pair of
wedged-shaped halves nearly sundered by the anus.

The mouth is smaller but otherwise similar in form and position
to that of G. nepheloidea. Diffuse salivary glands extend through
somites XII to XIV or sometimes farther. Never more than six
pairs of gastric czeca are present, but the number is variable and
may be reduced to three pairs by the obliteration of the first three.
All are simple and unbranched and increase in size from the first
to the sixth pair, the last being much the largest and reflexed caudad
through three or four somites (XIX to XXII).

The external genital orifices and the reproductive organs gen-
erally are essentially like those of G. nefheloidea. The longitudinal
muscle cells are arranged diffusely but are strongly developed.

Pale gray, pink, brownish or greenish tints, which are much
affected by the contents of the alimentary canal seen through the
more or less translucent tissues, are the colors of this species.
Young specimens and some adults are almost colorless and trans-
lucent, but commonly the tissues of the larger ones are rendered
opaque by the presence of numerous reserve and pigment cells.

THE LEECHES OF MINNESOTA =9

Habits—Judging by the material which represents it in this
collection this nearly cosmopolitan species must be much less
abundant in the lakes of Minnesota than in many other sections
of this country and especially the northeastern portion from Illinois to
Maine. It is found everywhere but abounds especially in warm
shallow waters of streams, pools and ponds and along the shores of
lakes and rivers; it is the common pond leech. In all suitable
localities it gathers in numbers on the under sides of stones, sticks
and fallen leaves or conceals itself between the ensheathing leaf
stalks of rushes and other aquatic plants. Less often it attaches
itself to the bodies of larger leeches, such as Macrobdella and
Haemopis, to fresh water snails, mussels, fishes, turtles and more
rarely to frogs. It is perhaps transported on the legs of aquatic
birds. Like most of the Glossiphonie it does not swim, but when
disturbed creeps with considerable activity to a place of conceal-
ment, when, if still further disturbed, it rolls into a ball in the man-
ner of a “pill bug” and falls to the bottom, then quickly unrolls and
creeps away to a dark shelter.

Ordinarily its food consists of small annelids, insect larve,
snails, and small bivalves like Pisidiwm and its allies. Numbers also
congregate and feed upon dead bodies of larger animals, such as
crustaceans, fishes and frogs; and when occasion offers blood will be
drawn from injured fishes, frogs and other vertebrates, including
the feet of wading boys. Vast numbers frequent the fishing stations
along the Delaware River, attracted no doubt by the quantities of
bloody offal thrown into the water at such places. Under such con-
ditions the stomach of every individual will be distended with blood,
and, comparing Castle’s description of the alimentary canal with my
own observations, I am led to suspect that the capacity of the
gastric caeca may be increased in individuals which habitually sub-
sist upon such diet.

On the other hand this little leech is frequently devoured by
the large predaceous leeches, sunfish, perch and other small carniv-
orous fishes. Along the shores of tidal rivers, like the Delaware,
various species of snipe and sandpipers, which feed on the flats ex-
posed at low water, pick them from the shingle and gravel.

Breeding begins in early spring and extends into the early sum-
mer. During the latter part of April and early May almost every
individual bears its burden of eggs or young. In streams and ponds
of cold water ovi-position occurs later than in warmer waters. In

80 THE LEECHES OF MINNESOTA

some localities a second brood is raised in late summer. As in most
closely related forms the eggs are not attached directly to the body
but are contained several together in small mucoid sacs, of which
mature individuals bear from eight to twelve or fifteen attached to
the posterior ventral surface. When bearing eggs or young the
rhythmic oscillating respiratory movements become much more
frequent and vigorous than at other times. When disturbed the
brood is protected by enveloping it in the margins of the body folded
toward the middle line and by rolling into a ball.

Glossiphonia fusca Castle.
(Plate I, fig: 3)
Clepsine papillifera var. lineata Verr. (1874)
not Hirudo lineata Muller (1774)
Glossiphonia lineata Moore (1898)
Glossiphonia fusca Castle (1900)

Description—The form is rather short and thick and relatively
broader than the other small Glossiphonie described in this paper.
In size it is about equal to G. stagnalis but lacks the great power of
extension of that species. Typically the back bears three longitu-
dinal series of small but prominent sharp conical papilla, an irregu-
lar median series, really formed of a pair of closely approximated
series reduced to one by fusion or loss of some of the members,
and two dorso-lateral series situated half-way between the middle
and the margins. Sometimes two more are added external to the
latter, one on each side, but these latter are always very incomplete.
There is a single pair of remarkably large eyes situated as in G.
stagnalis. No nuchal gland is present.

Somites I and II are uniannulate or completely united; III and
IV are biannulate, the larger annulus of the latter partly divided
by an incomplete furrow az/a2; V is generally triannulate dorsally,
but biannulate ventrally. Somites VI to XXIV are fully trian-
nulate, XXV and XXVI biannulate, the latter incompletely in most
cases, and XXVII uniannulate. The postanal annulus is very large.

The mouth is situated as in G. stagnalis but is rather larger and
the proboscis wider than in that species. There are six pairs of
gastric ceca, strictly simple or slightly lobed, and the first is some-
times wanting; the last reflexed as usual. The salivary glands are

diffuse but much more extensively developed than in the preceeding
species.

THE LEECHES OF MINNESOTA 81

The testes are present in the same number and occupy the same
positions as usual, each lying just anterior to the base of one of the
gastric ceca. A long posterior loop of the vas deferens, partly
enlarged as a sperm sac, is developed and extends through the
ventral sinus to somite XV or beyond.

The colors are plain but very pretty and exhibit a considerable
range of variation. The ground is ash or grayish brown, plain be-
low, but on the dorsal side generally marked by numerous narrow
longitudinal lines of brown pigment cells which give to that sur--
face a generally brown effect. The entire preocular region is per-
fectly white, and the neural annuli, for most of the length of
the body, are marked with two, four or six white spots arranged in
regular longitudinal series and flanking the three or five rows of
cutaneous papillae which, owing to their black color, are by contrast
very conspicuous. Sometimes the white spots fuse into metameric
transverse bars and more rarely they are absent.

Habits—This handsome little leech is much less common than
G. stagnalis, though in some localities it occurs in abundance along
with that species and G. complanata. It seems to be more partial
to colder waters than either of these species and is sometimes
found in springs where they do not occur. In ponds it frequently
fastens itself upon the shells of the larger species of Lymnza and
other snails and more rarely to the larger leeches. Less active
than G. complanata it feeds less frequently upon active worms and
larve but confines its attacks almost exclusively to the smaller snails.
snails.

In placing its eggs in a small number of large capsules this
species resembles G. complanata, but it breeds later than that species,
continuing far into the summer (as late as Aug. 6th) to carry newly
laid eggs. ;

Cencerning the name of this species it should be said that
Verrill’s name lineata, although the earliest, must be discarded on
account of Mullers earlier use of Hirudo lineata which is clearly a
Glossiphonia and probably G. complanata, though so far as I know
it has been definitely determined. Glossiphonia triserialis E.
Blanchard (1849) bears a remarkably close resemblance to our
species and was at one time regarded by me as identical with it,
but R. Blanchard has recently repeated (1900) his earlier statement
(1896) that the genital orifices are separated by two annuli in this
species and not by one as in G. fusca.

82 THE LEECHES OF MINNESOTA

Glossiphonia complanata (Linnzus) Johnston.
(Plate I, fig. 4)

Hirudo complanata Linneus (1758)
Clepsine elegans Verrill (1874)

Description—Although not much exceeding the species previ-
ously described in length when extended this leech is considerably
larger and more bulky than any of them. The body is rather broad
and flat with thicker margins, though G. fusca approaches it in this
respect, and like that species it is incapable of great extension. In
this connection it is interesting to note that both of these species
have remarkably well developed longitudinal muscles. The head
is not distinctly widened and the posterior sucker is small but pow-
erful and less strongly directed ventrad than in the large species of
Placobdella. There are at least four series of low, rounded but
rather large cutaneous papillze on which the dorso-median and
dorso-lateral sensilla are borne. There is no median series.
Numerous small sense organs roughen the integument, which is
rather opaque. A character which is quite unique among the
Glossiphonide herein described is the presence of three distinct
pairs of eyes situated on somites IJ, III and IV respectively. They
are close together near the middle line and the pigment cups of the
first are sometimes in contact, while the second are farthest apart
and the largest.in size. There is no nuchal gland.

Somites I and II are uniannulate, sometimes indistinctly sep-
arated; III is uniannulate or indistinctly biannulate; IV is biannu-
late, divided by a rather faint furrow into a larger anterior and a
smaller posterior annulus. The next somite (V) is biannulate or
more usually triannulate by the separation of ar by a shallow fur-
row from a2. Somites VI to XXIV inclusive are fully triannulate;
XXV is biannulate and XXVI and XXVII usually uniannulate,
the former frequently exhibiting some marginal division.

The mouth is of relatively large size and placed at the boundary
between the second and the third somites. Like the closely related
species the salivary glands are diffuse. Six or seven pairs of simple
or slightly branched gastric ceca are present, the last reflected but
relatively shorter than in the blood-sucking species of Placobdella.
The longitudinal muscles of this species are remarkably powerful.

Unlike the three species of Glossiphonia described above the
genital orifices of this species are separated by two annuli, the male

THE LEECHES OF MINNESOTA 8

io)

being situated at XI/XII, the female XII a2/a3. The vasa defer-
entia have the customary long posterior loops and enlarged sperm
sacs. A very remarkable feature and one that is peculiar to this
and a few very closely allied species is the presence of nine or ten
pairs of testes in place of the six pairs usually present. The addi-
tional pairs are added at the caudal end of the series in somites XX
topo TEE:

A more or less obvious narrowly striped pattern results from
the more superficial pigments showing through the rather opaque
integuments along the lines of the longitudinal muscles. The gen-
eral effect is a somewhat heavy green or brown ground color
marked dorsally and ventrally by a pair of very conspicuous longi-
tudinal brown lines which above begin just behind the eyes while
below they are slightly farther apart. The dorsal lines are broken
into a series of short dashes by small metameric white or sulphur
yellow spots corresponding with the dorso-medial papillae on the
neural annuli. Four or five additional series of similar spots occur
on the neural annuli, making six or seven in all. Of these the
median series is the least constant, the others including the four
constant papillz, to which two marginal series must be added.

Habits—The snail leech, as this species is named in England,
abounds in certain localities in the shallows of rivers and large
ponds, where it is found concealed beneath stones. It is remarkable
among the small glossiphonids for its great muscular strength,
which enables it to overcome its prey and to adhere to stones with
great tenacity. While more tardy in seeking to escape when dis-
turbed than its most usual associate, G. stagnalis, it is more active
in its movements when once aroused. It is more prone than most
species to roll into a ball and may remain quiescent in this condi-
tion for a considerable period.

Although occasionally found attached to turtles the snail leech
has not been observed to suck blood, but so far as my observations
extend feeds exclusively in its natural habitat on small snails, worms
etc., which its strength enable it to quickly overcome.

As usual the eggs are carried on the ventral side of the body
and their large number, as well as the great length of the breeding
season, render this one of the most satisfactory species for embryo-
logical study. It is one of the earliest as well as one of the latest
of the Glossiphonias to bear eggs, which are contained in a small
number of unusually large capsules.

84 THE LEECHES OF MINNESOTA

Genus Placobdella R. Blanchard.

Body widened and moderately or excessively depressed. Suck-
ers variable, the caudal sometimes with minute marginal serrations.
Eyes usually one pair, compound, on somite III, rarely followed
by several pairs of imperfect simple eyes. Cutaneous papillae vari-
able, but usually numerous and some median. Pharyngeal salivary
elands large and compact; gastric ceca seven pairs, very large and
much branched in the flatter species. Sperm ducts without loops,
compacted and much convoluted. Parasitic on turtles, fishes and
batrachians, or free-living.

Placobdella parasitica (Say) Moore.
(Plate I, figs: 7,8)

Hirudo parasitica Say (1824)
Glossiphonia parasitica Castle (1900)
Placobdella parasitica Moore (1901)

Description—Of all of our numerous species of glossiphonids
this attains the largest dimensions. Ordinarily examples are about
two inches in length when extended, the giants upwards of four
inches in the same condition. The form is broad, very flat and
foliaceous particularly when food is absent from the ceca. In ex-
tension the head is somewhat expanded, but in contraction partakes
of the general ovate pyriform outline of the body. The posterior
sucker is of large size and considerably exposed behind the body,
the plane of its adhesive surface being parallel with the ventral
surface of the body. Cutaneous papillae are numerous but incon-
spicuous, low and smooth; sometimes they are obsolete. The most
constant are disposed in three longitudinal series on the neural
annuli and two longitudinal series on the post-neural annuli. Those
of the median series are not enlarged but on the contrary are usually
smaller than those of the paired series.

The annuli and the somite limits are well defined, the furrows
exhibiting certain constant differences in depth. Somites I and II
are united in the reduced prostomial lobe, which may, but usually
does not present a faint cross furrow; III and IV are triannulate, the
anterior annulus in each case being much the larger. Somite V is trian-
nulate dorsally but the furrow ar/a2 is faint and becomes obsolete on
the ventral side. There is a very gradual deepening of the furrow
ar/a2 on the succeeding somites, but VI to XXIII or sometimes

THE LEECHES OF MINNESOTA

[o7e)
ou

XXIV may be considered to be fully triannulate, as this furrow,
though not so deep as the others, is complete. The first annulus
(ar) is always more closely united with the second (a2) than is
the third (a3). The furrows correspond closely on the dorsal and
ventral surfaces. Somite XXIV is usually simpler, owing to the
incompleteness of the furrow a2/a3 toward the mid dorsal region.
XXV is biannulate at the margins only, the furrows disappearing
mesiad; XXVI and XXVII are normally uniannulate.

The small, pore-like mouth is in II]. The salivary glands are
compact and with a median lobe. As usual in this genus there are
seven pairs of large spreading gastric czeca, in this species exten-
sively developed and reaching almost to the margins of the body
as fine lobes more numerous than in any other Minnesota species.
The last pair is the largest and reflexed as far as somite XXII.

Small male and female orifices are located in the furrows
XI/XII and XII a2/a3 respectively. The testes are six pairs, the
sperm sacs long but closely and complexly folded in somites XI
and XII by the sides of the atrium.

The coloration is very rich and striking but extremely variable.
The ground color of the dorsum is dull green, olive green or brown,
marked with bright yellow which may replace the ground color very
extensively. Usually the yellow is confined to the following regions:
—A continuous or interrupted longitudinal median band which
widens and narrows alternately at intervals of about three somites,
regular marginal spots covering the intervals between the successive
neural annuli, and large irregular blotches constituting an inter-
mediate series which often become confluent with one another or
with the marginal spots or both. The ventral surface is longitu-
dinally striped with light and dark the whole having a peculiar blu-
ish or purplish reflection. Dorsal integuments rather opaque.

Habits—Living chiefly as a parasite upon the snapping turtle
on whose blood it feeds voraciously. The geographical range of
this species is largely determined by that of its principal host. As
the snapping turtle is an important article of commerce this leech
is very well known and is reported from all parts of the United
States. Its habits are too familiar to require description though it
is not so widely known that the species also lives a free life par-
ticularly when carrying eggs or young and feeds on aquatic worms
etc.

&6 THE LEECHES OF MINNESOTA

Placobdella rugosa (Verrill) Moore.
(Plate. 1, 20.29)

Clepsine ornata var. rugosa Verrill (1874)
Placobdella rugosa Moore (1901)

Description—Placobdella rugosa is a large leech, nearly or
quite equalling P. parasitica, although the great majority of ex-
amples met with average considerably smaller than that species.
In form it is even more depressed, starving individuals being
scarcely thicker than a card, very broad and leaf-like. The head
is essentially similar to that of P. parasitica but as this leech does
not extend itself as fully as that it is seldom seen in the distinctly
expanded state. The caudal sucker is large and elliptical rather
than circular, the antero-posterior diameter being slightly greater
than the transverse. An important characteristic is the presence
of numerous large rough cutaneous papillae on the dorsum. The
principal ones are constant in arrangement but the number of
smaller ones is quite variable. Most characteristic and conspicuous
are five on each neural annulus, median, supra-marginal and inter-
mediate in position and forming five longitudinal series as far
caudad as somite XXIII, posterior to which the median papillz
become greatly reduced in size and overshadowed by paramedian
papilla in line with the dorso-median sensille. On ar the papille
are all relatively small while a3 bears some of large size inferior
cnly to the largest on a2. The integument is translucent.

Scemites I and IT are uniannulate and always distinctly sepa-
rated; II] is biannulate with a faint furrow usually discernible
across the larger anterior annulus, on the posterior division of which
are seen the small compound eyes, often included in a common
pigment mass. Somite IV is triannulate dorsally but az/a2 is less
distinct than the other furrows; V is triannulate dorsally, biannu-
late ventrally. The fully triannulate somites are VI to XXIII in-
clusive, and this species shows in a much less convincing way the
transitional steps between biannulate and triannulate somites. In
all of the complete somites a noteworthy feature is the lack of
alignment between the dorsal and ventral furrows, as a result of
which a2 is the longest annulus dorsally but the shortest ventrally.
Of the posterior simpler somites, XXIV is triannulate dorsally with
a3 of very much smaller relative size and incompletely separated

THE LEE CHEStOR MINNESOTA 87

from a2 on the ventral side, XXV and XXVI are wholly or partially
biannulate and XXVII uniannulate.

The alimentary canal is nearly as in P. parasitica but the
compact salivary glands have no median lobe and the divisions of
the gastric czca, although long, are less numerous. The repro-
ductive organs are essentially similar in the two species, with the
sperm sac, epididymis and ductus ejaculatorius compactly folded in
somites XI and XII.

Owing to the numerous papillz and the translucency of the
skin the colors are a somewhat confused mixture of light and dark
browns, yellows and greens, based upon a fundamental pattern
similar to P. parasitica and consisting of a variegated brown ground
with light intermetameric marginal spots, a median dorsal light
stripe interrupted by short dark brown or brownish green longi-
tudinal lines, which sometimes unite into a continuous dark line,
and numerous small light yellow or green spots corresponding to
the papillz and sensillz. The ventral surface is plain gray or light
brown without longitudinal stripes.

Habits—Placobdella rugosa, the rough leech, is a very frequent
inhabitant of streams and ponds, where it may be found clinging
to the under side of stones and floating wood, especially during the
late spring and early summer. At other seasons they are some-
times found upon aquatic turtles upon whose blood they in part
subsist. Leeches of this species are sluggish and when exposed in
their resting places press the flat body closely to the stone or log,
whose colors they so closely simulate, and trust to this protective
resemblance to escape detection, rather than creep actively away in
the manner of many other species of allied leeches. The close
resemblance to surroundings is much enhanced by the fact that
particles of mud adhere to the mucous and rough papillae. Further-
more the leeches may partially bury themselves in the bottom sedi-
ments. They seldom swim and when thrown into the water roll
up and sink passively to the bottom, upon reaching which, they
creep to a place of concealment in a most deliberate fashion.

So far as has been actually observed no other food than blood
is taken though it seems probable that the juices and even the solid
parts of small aquatic invertebrates may serve the same purpose,
as is certainly the case in the nearest ally of this species.

The large chitimoid spermatophores may be observed as fre-
quently and easily as those of P. parasitica which they closely re-

88 THE LEECHES OF MINNESOTA

semble in form and mode of fixation. The eggs are very numerous
and are fixed lightly to the ventral surface of the body covered by
a delicate mucoid membrane. During the period of incubation the
parent leech attaches itself firmly and is very loath to leave its
resting place. If, under such circumstances, force be used the
leech holds tenaciously by both suckers to its support and curls
the lateral margins of the body in such a manner as to enclose the
eggs or young. As a result of a struggle to remove the brooding
leech the eggs are generally detached and are then sometimes found
to be adherant to the stone or glass of the aquarium against which
they have been pressed. When forcibly removed from the eggs the
leech will usually seek and return to them.

Placobdella montifera nom. noy.
(Plate J, fie: 5, Plated, fe. 10)

Clepsine papillifera var. carinata Verrill (1874)
Not Clepsine carinata Diesing (1858)
Hemiclepsis carinata Moore (1901)

Description—The size is moderate, never approaching the
maximum of the two species of the genus already described. In
addition to the widely expanded discoid head, which is quite char-
acteristic, the form is more slender and less flattened and foliacious
than usual in the genus. The posterior sucker is large, circular,
rather freely pedicillate and minutely denticulated about the mar-
gins. The oral sucker also possesses unusual mobility, has a promi-
nent free margin all around and a narrow unsegmented border. The
capacity for extension and contraction exceeds that of either P.
parasitica or P. rugosa. The dorsum bears three rows of very large
conical papillae situated on the second and third annuli of each
somite for the greater part of the body as far as somite XXI. These
are borne on the crests of three prominent nearly continuous ridges.
On somites XXII to XX VI the three tuberculated keels cease and
are replaced by a pair of large paramedian papillae on each somite.

The anterior somites are better developed than in the closely
related species, no doubt in correlation to the formation of the
distinct head, into which the first five enter. The first two are each
faintly biannulate, III is distinctly biannulate, with az obscurely sepa-
rated as a small anterior ring, behind which is situated the pair of small
eyes. There are seventeen completely triannulate somites (VI to

THE LEECHES OF MINNESOTA 89

XXII inclusive). In the neck-like constriction between the head and
body is a peculiar double annulus which is interpreted as V az. In the
complete somites the three annuli increase in length caudad and a3 is
partly cut into two by marginal furrows. Somites XXIII and XXIV
are triannulate at the margins only, the third annulus of each being
the least developed, and the furrow XXIV arz/a2 deficient mesially.
The two following somites (XXV and XXVI) are further simplified
in the direction indicated in XXIII and XXIV. They are incom-
pletely biannulate with only traces of a2/a3; XXVII is uniannulate.
Three well marked post-anal annuli form the narrow portion of the
sucker pedicle.

The mouth is small in somite Il; The proboscis is long and slender
and the cesophagus of about equal length. There are the usual
seven pairs of capacious gastric ceca divided into numerous lobes
which reach almost to the margins of the body; the first sends a
long anterior lobe forward into somite XI and the last reaches from
XIX to XXIII. The salivary glands are compact and rather small.

While conforming in every important feature to the general
plan characterizing the other members of this genus, the repro-
ductive organs are somewhat peculiar in the shorter and more
loosely folded sperm sacs.

The color is generally a dull greenish gray or pale olive brown
with an interrupted dark green or brown median dorsal line, a
series of obscure light yellow marginal spots or a marginal yellow
border, more or less interrupted on the neural annuli, and spots
of the same color, often including green flecks on the papillae. A
deeply pigmented green and brown spot marks the otherwise pale
colored head. The ventral surface is plain.

Habits—This very interesting keeled leech exhibits little of
that marked gregariousness which is common to most other mem-
bers of the family. It is met with far more frequently singly than
in company. As a parasite it devotes itself especially to frogs and,
when they frequent the water during the breeding season, to toads.

It also habitually enters the shells of living mussels, though
it is not known definitely that it feeds upon their soft tissues.
Meadow brooks and swamps adjacent to the shores of lakes and
ponds are its favorite haunts, where it lives among water plants and
beneath stones as well as upon the bodies of frogs. Nothing is
known of the breeding habits beyond the bare facts that spermato-
pores are deposited in early spring and that the young are carried.

90 THE LEECHES OF MINNESOTA

Although Verrill was the first to describe this species, his
name, which I used in a former connection when the species was
erroneously referred to Hemiclepsis, is preoccupied by Clepsine
carinata Diesing (1858) which is unquestionably a Placobdella.
The name montifera is therefore proposed as suggestive of the resem-
blance of the carinz to conventional mountain ranges.

Placobdella Pediculata Hemingway.
Plate II, Figs. 13-18.

Placobdella pediculata Hemingway, American Naturalist, Vol.
XLII, 1908, pp. 527-532, figs. 1-3.

Description*—Like Placobdella parasitica and P. rugosa this
species reaches a large size, though no specimens quite equal-
ling the largest examples of these, its allies, have been seen.
Judged by the poor state of preservation of the few adults that I
have examined it is in life soft-bodied and more than usually
contractile. All of these specimens—numbering six—are gorged
with blood and in this state are thick and hard in the region of
the body occupied by the gastric ceca. All are strongly con-
tracted and have the very characteristic pyriform outline and
strongly convex dorsum evident in the figures, but the most strik-
ing peculiarity is the abrupt contraction and attenuation of the
posterior segments to form a narrow pedicle supporting the cau-
dal sucker, which, consequently, stands out freely exposed be-
hind the wide posterior part of the body in a most characteris-
tic manner. Hemingway has made the interesting discovery that
this condition arises in the course of individual development and
does not exist in young leeches one centimeter long, which con-
sequently differ less obviously than do the adults from related
members of the genus. The oral sucker, as far as can be de-
termined in its contracted state with the lip inrolled, has the same
structure as in P. parasitica.

The skin is perfectly smooth, without a trace of cutaneous
papilla; and only a few obscure segmental sensilla and Bayer’s
scattered sense organs, the latter chiefly near the margins of the

*This description is printed substantially as originally prepared for
this repert but several important additions and corrections, for which I am
indebted to Hemingway’s paper, are either bracketed or specifically cred-
ited to that source.

THE LEECHES OF MINNESOTA gl

body, were detected. Undoubtedly suitably preserved material
would exhibit the sensille typically distributed and essentially as
they occur in related species. Eyes are very difficult to detect in
surface views of preserved adults but small pigment masses occur
at III/IV in the same position as in P. parasitica and (distinct
eyes appear at III/IV inthe young). However, it has not been
determined whether the eyes are simple or aggregated.

In spite of the obscurity due to great and often unequal con-
traction of the annuli a careful analysis of the external mor-
phology shows that, except for the caudal peduncle and an appat-
ently greater simplicity of corresponding anterior segments of P.
pediculata, the structure is essentially as in P. parasitica. In respect
to the annulation the condition existing in young leeches must be
accepted with some caution as the somites become increasingly
complex with growth and age. The annulation of somites I to
IV of adults is unknown but in the young (I and II contain each
but a single annulus and III and IV are biannulate). Somite V
is biannulate dorsally but ventrally the furrow fades away to-
ward the median line; VI is triannulate at the margins but the fur-
row al/a2 is incomplete above and even more so below. Somites
VII to XXIII (or XXIV) are triannulate but the furrow al/a2 is
incomplete medially on the venter of both VII and VIII and on
most of the succeeding somites is less marked than either a2/a3 or
the intersegmental furrows. On anterior somites, and, to a less de-
gree on the posterior a3 is slightly longer than al or a2.

The annulation of the post-anal somites, constituting the
caudal peduncle, is irregular and somewhat puzzling on the adult
specimens, but here also most of the somites, while very short,
appear each to be made up of three small annuli of varying size
and incompletely defined limits. Figure 16 represents accurate-
ly the exact arrangement of the furrows. On young specimens
(somite XXIV is triannulate, XXV, XXVI and XXVII are all
biannulate but al of somite XXV is partially divided and al of
both XXVI and XXVII is larger than a2). Somite XXIV, which
immediately succeeds the anus, is the last segment of the body
proper and on the contracted specimens its posterior border forms
a fold which envelopes the contiguous portions of the narrow ped-
uncle. The latter continues to taper to the sucker, to the middle
portion of which it is strongly attached for rather more than the
posterior half. The posterior sucker is large, circular and directed

92 THE LEECHES OF MINNESOTA

strongly ventrad. (The disc is composed of somites XXVIII to
XXXIV.) The few nephridopores that are visible.are situated as
in P. parasitica.

The mouth is very small and is situated far forward near
the anterior rim of the sucker in somite II. As in related species
the proboscis is slender, the cesophageal glands compact and the
stomach provided with seven pairs of large ceca reaching nearly
to the margins of the body. The ceca are less deeply divided and
simpler than those of P. parasitica, each of the first six pairs present-
ing only two or three rather short lobes. The intestine reaches to the
posterior part of somite XXIV or even beyond and then bends ab-
ruptly forward toward the dorsum as an extremely narrow rectum
to the’anus situated at XXIII/XXIV. The forward curvature of the
rectum and the anterior position of the anus are unique features in the
family.

The reproductive organs are essentially similar to those of
P. parasitica. The male and female external orifices are situated
respectively at XI/XII and XII a2/a3. Six pairs of testes are
crowded between the bases of the gastric ceca. The large sperm
sac and ejaculatory duct of the vas deferens form a compact snarl in
somite XII in the immediate neighborhood of the atrium.

In addition to the type specimen taken by Professor Nachtrieb
from the isthmus of a sheepshead at Lake Pepin, the writer has
also examined specimens in the collection of the Illinois State Lab-
oratory of Natural History taken from the same host at Henry and
Peoria, Illinois.

Habits—Hemingway gives the following account of what is
known concerning the interesting habits of this leech :—

Placobdella pediculata appears to be a true fish parasite, having
been found only in the gill chamber of the freshwater sheepshead
(Aplodinotus grunniens), the posterior sucker of the leech being
deeply imbedded in the side of the isthmus or shoulder. In the
case of young leeches which have not been long attached, the de-
pression caused by the posterior sucker is comparatively shallow,
being a mere external depression in the inflamed tissues of the
fish. As the attachment continues the inflamed tissues of the host
grow up like a collar and close in around the leech’s body in front of
the sucker. This closing in of the inflamed collar pregses upon the
body of the leech, narrows it to a slender peduncle in front of the
sucker and incidentally crowds the sucker down into the tissues of

THE LEECHES OF MINNESOTA 93

the fish, so that, in time, this depression may reach into the underlying
muscles of the host to a depth of half an inch or more and have an
opening of about a quarter of an inch or less in diameter. The bot-
tom of the depression has a larger diameter. Figure 5 of plate C repre-
sents the positions of three depressions from which the leeches have
been removed, and figure 6 represents one of the depressions cut in
two lengthwise.

These leeches are capable of becoming greatly contracted and
when one is disturbed it draws back until it appears as a mere
brownish pyriform knob which entirely covers the place of attach-
ment.

The burying of the posterior segments in the tissues of the
host has brought about an interesting structural change, so that
we find the anal opening shifted forward to a position between
somites XXIII and XXIV instead of between somites XX VII and
XXVIII as in the other members of the genus. It is noticeable
that, while the young leeches whose posterior portions are not yet
deeply imbedded have the characteristic position of the anus
(XXIII/XXIV), the outline of the posterior part of the body is
still a regular curve showing none of the pedicular characteristics
so pronounced in the older individuals. The posterior sucker, how-
ever, is very strongly developed even in those not more than a
centimeter long.

Practically nothing is known of this leech separate from its
host, but it seems possible that a part of its existence may be spent
elsewhere. During September, 1903, I examined several thousand
specimens of the sheepshead from Lake Pepin and found only three
isolated leeches, each about a centimeter in length., The posterior
sucker, while imbedded in the tissue, was not sunk in deeply and
so had not produced the characteristic peduncel. They were evi-
dently young ones which had recently attached themselves to their
hosts and were gradually sinking the posterior sucker into the
host’s flesh. As full grown specimens, deeply imbedded, were
found in the same locality during August of 1899, at least some of
the adults must remain with their hosts during the summer and
probably thruout the year.

>

04 THE LEECHES OF MINNESOTA

Placobdella hollensis (\Whitman)
(Plate Tl, fie. 11)

Clepsine hollensis Whitman (1892)

Description. This very distinct species will retain a perma-
nent interest for zoologists because of its having furnished the
material for Whitman’s classical analysis of the nervous system
of the leech. Its place in the fauna of Minnesota ts established by
several examples taken in Poplar Lake near St. Paul and sent to
me with other leeches by Prof. Henry L. Osborn.

The form is very similar to P. parasitica but the present
species is a very much smaller leech, a length of from one to one
and one-half inches being about the usual size, though individuals
reaching two inches in extension have been observed. The. most
obvious external characteristic is found in the eyes. As in other
species of Placobdella a pair of large contiguous compound eyes
exists in somite III with their bases resting in a conspicuous pig-
ment mass and their principal visual component directed forward.
But unlike the other species described this pair is succeeded by an
indefinite number of pairs of much smaller eye-like organs which
Whitman has shown to be the modified dorso-median sensillz,
which possess a diminishing number of visual cells in each succes-
Sive pair toward the caudal end, and gradually pass into the ordi-
nary sensilla. Superficially each appears as a small clear or whitish
area anterior to which more or less black pigment is accumulated
in the form of an irregular cup. The first pair (on IV) is decidedly
prominent and those on V and VI are also quite conspicuous and
eye-like. At first sight, therefore, this might be described as an
eight-eyed leech, with the first pair of eyes directed forward, the
remaining three, which are smaller and simple, backward. More
careful examination shows that the same features exist in a lessen-
ing degree in several additional pairs of the dorso-median and some
of the dorso-lateral sensillz as well, making it quite impossible to de-
termine just where the visual possibilities of the sensillze cease. All
of the sensillz are very distinct, rendering this a very favorable object
for study on this subject.

The back is more or less roughened with small sense organs
and a few larger round smooth papillae. The latter correspond to
the largest papilla of P. rugosa and are most prominent posteriorly.
In the Minnesota specimens they begin on the neural annulus of

THE LEECHES OF MINNESOTA 95

VIII and by somite X present the following typical arrangement:
The neural annulus bears a median one and a pair just mediad of
the dorso-lateral sensilla. 43 bears a pair directly in line with the
dorso-median sensillz and az a smaller median one.

This species exhibits the same gradual development of the bian-
nulate and triannulate somite as P. parasitica and consequently pre-
sents the same difficulties in the application of a formal descriptive
terminology. Somites I and II may be considered as uniannulate, ITI,
IV and V as biannulate, VI as transitional and VII to XXIV or, XXV
as triannulate; XXVI and XXVII exhibit partial subdivision only at
the margins. The complete somites of the middle region of the body
show the same tendency of the sub-division of az and a3 into secondary
annuli that is exhibited by P. rugosa. In the internal anatomy a con-
siderable number of minute differences between this species and
P. parasitica have been observed, but the general and obvious structure
of the alimentary canal and reproductive organs of the two species is
essentially alike.

The colors as described from living eastern representatives of
the species are rather characteristic. The dorsum is generally a light
olive green varigated with brown, pale yellow, and colorless areas.
The head end lacks pigment almost entirely except what -is concen-
trated about the eyes and in the transverse bands on the neural annuli.
This light area extends caudad for some distance as a median vitta
between the pairs of small eyes. On the neural annuli it is usually
interrupted by the transverse bands of interocular pigment between
which it is flanked by dark cloudings which more posteriorly takes
the form of a pair of dark longitudinal bands just mediad of the dorso-
median sensille. At about somite X and thence caudad, the median
vitta and its dark flanking bands are transformed into a chain-like
pattern consisting of alternate dark bars and elliptical rings with light
centers, the former extending over about two somites and the latter
one somite, there being about five of each. Posteriorly an elongated
light median area represents several of the rings coallesced.

The larger cutaneous papillae are of a light yellow or cream color
and those of the most medial neural series interrupt the dark bands
described above. A similar yellow color occurs along the margins,
alternating in blocks with the green ground color. In many speci-
mens narrow bands of dark pigment extend across the entire dorsum
of the anterior neural annuli and less frequently all or nearly all of
the sensilla are flanked on the medial side by brown or black pig-
ment. The ventral surface is nearly plain.

96 THE LEECHES OF MINNESOTA

Habits. This very interesting leech bears the same relation to the
smaller fresh water tortoises that P. parasitica does to the snapping
turtles and other large species. Not every tortoise is parasitized but
as a rule several of the leeches are found associated together on each
one so affected. The species also frequently occurs on the under side
of floating wood in ponds inhabited by tortoises. In its movements
it is more active than other species of Placobdella and swims with
much greater facility than any other, not excepting P. montifera. The
spermatophores and breeding habits are very similar to those of P.
parasitica and P. rugosa.

Genus Hemiclepsis Vejdovsky.

Form variable, usually rather wide and moderately depressed;
tissues soft and almost cedemous, translucent. Suckers as in Glossi-
phonia. Eyes usually four pairs, in longitudinal series near the median
line. Cutaneous papilla few and low. Pharyngeal salivary glands
diffuse; gastric czeca nine or ten pairs, branched. Genital pores as in
Glossiphonia, but sometimes farther apart. Chiefly free-living.

*“Hemiclepsis occidentalis (Verrill)
(Plate: ll, fig: 5122)

Clepsine occidentalis Verrill (1874).

Description—This rare and very interesting leech is represented
in the Minnesota collection only by a batch of young, evidently re-
moved from the parent which carried them, and is consequently
described from specimens received from other localities, though the
anterior end of one of these young is represented in the figure. The
leech is of moderate size, about one and one-half inches being the limit
in extension. In life it is of a rather slender form, broadly rounded
anteriorly where there is no definitely expanded head, moderately de-
pressed but rather thick at the margins posteriorly and with a very
large caudal sucker. A noteworthy feature which separates this from
every other species described in this paper is the peculiar transparency
and gelatinous consistency of the body.

There are four pairs of large conspicuous eyes, which cannot be
mistaken for the much smaller ones of .Placobdella hollensis. They
are situated on somites II to V respectively; the first pair is the

*The name Protoclepsis Livanow (1902) proposed for this group is pre-
occupied by Protoclepsine Moore 1808.

THE LEECHES OF MINNESOTA O7

smallest and very close together or even in actual contact, the others
are successively more distant and the third pair is the largest. The
first and second are directed forward and outward, the third and
fourth backwards and outward.

The upper lip is very mobile and in preserved examples is almost
invariably curled into the cavity of the sucker. The small mouth is
far forward in somite II. Genital orifices occur at the positions so
frequent in the Glossiphonide, the male at XI/XII, the female at
XII a2/a3. In one specimen the male bursa is everted in the form
of a short conical penis, this being the only species of the family de-
scribed in this paper in which such an organ is present.

Besides the numerous scattered sense organs which roughen the
skin there are three pairs of low dome-shaped papille on each neural
annulus except at the anterior end of the body. Apparently these
bear the dorso-median, dorso-lateral and dorso-marginal sensille, the
first of which are separated by about one-fourth of the width of the
body.

With the exception of somites X, XI and XII, on which they can-
not be detected nephridiopores occur on a2 of every somite from
VIII to XXV. Very little is known of the internal anatomy of this
species but quite enough to establish its position as a member of the
genus. The proboscis is very short and is succeeded immediately by
a very short cesophagus and a long stomach which bears nine pairs
of branched ceca, two of which are anterior to the reproductive
orifices and the last reflected in the usual manner. The muscular
system is very peculiar in the wide intervals which exist between the
bundles of muscle fibers.

The color of preserved specimens is a translucent grayish green,
the dorsum being rather thickly spotted with cream yellow, the largest
spots corresponding with the six series of papilla described above.

The annulation presented in figure 12 should not be taken as
fully characteristic of the species as it exhibits the somites in the un-
developed biannulate or nearly biannulate condition which is observed
in the young of all species. With a more pronounced development of
the furrows between ar and a2 it would, however, be diagnostic. In
the adult somite I is a distinct but small preocular lobe, IT nearly and
IV fully biannulate. A very interesting feature, which is found in
all of these young and in the few adults which I have studied, is that
somite V is shorter and much less elaborate than IV. Somite VI ap-
proaches the triannulate type very closely and VII to XXIV inclusive

98 THE LEECHES OF MINNESOTA

are completely triannulate ; their annuli and furrows are all equal.
Finally XXV is biannulate, XXVI biannulate or uniannulate and
XXVII_ uniannulate.

It is not at all certain that this is really Verrill’s Clepsine occi-
dentalis as at least two and perhaps three other species of eight-eyed
glossiphonids are found in this country.

Habits—An eastern species of Hemiclepsis has been observed in
the living state and it is probable that the habits of the form described
will not depart much from this. The most striking peculiarity is its
remarkable activity. No other members of the family creep with
anything approaching its speed. In creeping the caudal sucker is
brought forward into actual contact with the oral sucker and the move-
ment is repeated with great rapidity. So far as has been observed the
species is entirely sanguivorous, the blood of frogs being taken while
worms and snails are refused. The European H. tessellata is known to
attack water fowl and to be transported while attached to their legs or
within the nasal chamber which it occasionally enters. Fertilization
takes place by means of spermatophores attached to the skin, but egg
laying has not been observed.

Family Ichthyobdellide.

Leeches of small, medium or large size. Form much varied;
short and stout or elongated and slender, terete or depressed, usually
more or less divided into a narrower anterior and an expanded pos-
terior region. No distinct clitellum, but diffuse clitellar glands abun-
dant. Segments smooth, or more rarely papillated, often provided
with lateral pulsating vesicles or gills on a certain number of segments.
Complete somites with from 2 to 14 annuli, greatly varied in pro-
portions. Both oral and caudal suckers usually large and deep and
more or less prominently set off on pedicles. Eyes 1 to 3 pairs widely
separated on posterior part of head, often absent. Eye spots often
on caudal sucker. Mouth and proboscis as in Glossiphonid@e; stomach
straight and usually simple, only rarely with lateral ceca, one pair of
large posterior gastric czca, variously and sometimes completely
united. Genital orifices much varied in position according to the num-
ber of rings per segment. Testes usually five or six pairs, the sperm
ducts relatively short, the epididymis and ejaculatory duct not much
convoluted, ending in an atrium that may be simple or more or less
complex ; no filiform penis. Ovisacs paired or united into one, pyri-
form or globular, their ducts simple. Eggs laid in usually stalked

THE LEECHES OF MINNESOTA 99

cocoons. Chiefly semi-permanent parasites on fishes, sometimes on
crustaceans. Nearly all are marine. Piscicola and closely related
genera only are found on fresh water fishes.

Genus Actinobdella Moore.

Rather slender and elongated, moderately depressed or half
round. Oral sucker slightly developed; caudal sucker large, deep,
and provided with a circle of numerous marginal papillae and glands.
A few dorsal papillz, some median. Complete somites of six unequal
rings. Eyes, one pair on III, united. Pharyngeal salivary glands
diffuse ; gastric caeca seven pairs, branched. Genital orifices separated
by four rings; sperm ducts lacking long loops, moderately compact.
Small blood-sucking leeches, probably parasitic on fishes.

Actinobdella inequiannulata Moore.
(Plate III, fig. 19, 20.)

Actinobdella inequiannulata Moore (1901)

Description—The collections from Lake Pepin included an ex-
ample of this very interesting species, the second one known, which
enables me to confirm and extend, and in some particulars to correct,
the original description. This additional knowledge renders more
evident than before the position which Actinobdella occupies on the
border between the two families of Ichthyobdellide and Glossi-
phonide, in fact the mere numerical weight of its characters as now
known point rather toward an alliance with the latter. As I hope soon
to have sufficient material to permit a thorough anatomical study the
discussion of its zoological position can best be postponed. The Lake
Pepin specimen measures 12 mm. in length and has nearly the form
of the type except that the middle region of the body is somewhat
widened. The following description is nearly a transcript from the
original with such changes and additions as further knowledge neces-
sitates.

The form is slender and depressed throughout, with the dorsal
surface convex, the ventral flat and the margins sharp. The breadth
is nearly equal or somewhat greater in the middle region, but con-
tracts suddenly at the posterior end to constitute the narrow pedicle
of the conspicuous caudal sucker, and at the anterior end tapers gently
to the broadly rounded upper lip.

There is no conspicuously expanded anterior sucker or head as
in typical ichthyobdellids, but this end of the body is formed exactly

fob THE LEECHES OF MINNESOTA

in the fashion of a glossiphonid. Four somites of simple structure
enter into its composition, the posterior ventral rim being formed by
the fourth and fifth somites in that region largely coalesced. On the
middle of-somite III is situated the single pair of small eyes conjoined
in a single median pigment mass and looking forward and outward.
Some detached pigment cells occur caudad and lateral of this position.

Most remarkable of all of the external features of this leech is
the posterior sucker. It is much wider than any part of the body,
largely free around its entire circumference and supported by a narrow
central pedicle. The ventral surface is very deeply cupped and the
rim somewhat contracted, making the diameter of the opening some-
what less than that of the internal cavity. From the internal face of
the sucker, a short distance back from the sharp margin, spring about
thirty (thirty in one, twenty-nine in the other, specimen) slender
finger-like papille which project more or less freely beyond the
margin. Owing to their contractile nature they vary in length and
diameter but when extended the longest are about .4 to .5 mm. in
length and about .1 mm. in diameter. Each one contains an axial
gland duct or group of ducts surrounded by a sheath of muscle fibres
which spring from the muscular ridges passing radially down the
inner face of the sucker. The gland ducts arise from a circle of glands
which appear as a circle of whitish spots arranged around the sucker
about midway between the margin and the pedicle and which raise the
outer surface into a slightly marked encircling ridge.

A median series of rather prominent conical papille with the
long diameter of their elliptical bases directed in the longitudinal axis
of the leech occur on the large annuli b3? and b5. In the Lake Pepin
specimen these papillae begin on VIII 65 and continue to XXVI b3;
in the type they are distinctly developed only on the somites XI to
XXV inclusive. In the new example also traces of supra-marginal
and intermediate series of papillze are found on the somites of the
middle region. Segmental sensille are very beautiful and regularly
shown in this specimen on all of the somites and both dorsally and
ventrally. The position of those found in the type and shown in the
figure of that specimen is confirmed and in addition the presence
of supra-marginals and of six ventral series is established. Thus it
will be seen that the sensilla have the arrangement characteristic of
the Glossiphonide. Well developed rings of small sense organs are
visible on annuli b2, b3 and b5 of each of the complete somites and
are more or less discernible on all primary annuli and more compre-
hensive divisions throughout the body.

THE LEECHESYOFr MINNESOTA IOI

Somites I, II and III are each uniannulate; IV is also practically
uniannulate but shows some signs of division above in the Pepin ex-
ample and below is largely united with V. The latter, together with
VI and in the type, VII also, is biannulate, an interesting feature be-
ing the rather larger size of second annulus. Somite VIII is quadrian-
nulate, being composed of az/a2/b5/b6, the latter two being very nar-
row.

Somites IX to XXV inclusive may be regarded as complete, but
some individual variations are exhibited and especially the first two
and the last are transitional. In the original specimen the complete
somites are sexannulate, the full number of secondary annuli being
developed, but of very unequal size. Two annuli, (b3 and D5)
are enlarged, the latter most so, and bear the dorsal cutaneous
papillz, and the former the metameric sensille as well; br, b2 and b6
are about equal and by is the smallest of all. The small annuli b7, b+
and b6 appear to be entirely unadorned, while b2 like the large papil-
lated annuli exhibits a circle of sense organs.

The conditions in the new specimen are essentially similar, but
the somites are somewhat further elaborated. Somite VII is triannu-
late rather than biannulate, VIII has the small annuli br and bf
rather distinctly separated and there is a very strong tendency in the
anterior part of the post-clitellial region toward the splitting off of
small additional annuli from the anterior margins of the enlarged an-
nuli b3 and b5 which leads toward the production of octannulate
somites. A trace of this is indicated in some of the somites of the
type specimen as is shown in the figures.

The remaining pre-anal somites XX VI and XXVII are typically
triannulate. Two post-anal annuli are present in the type and four
in the new specimen.

A few anatomical facts gleaned from the Lake Pepin specimen,
though very fragmentary, are nevertheless of great interest; for it
will be seen that in all essentials the alimentary canal is constructed
on the plan prevalent in the Glossiphonide. The position of the
mouth at the extreme anterior margin of the oral sucker in somite II,
or perhaps even in I, is paralleled in the Ichthyobdellide only in Not-
ostomum (Levinsen 1881). The probscis is long and slender, reach-
ing when retracted, from VI to X, at its posterior and receiving ap-
parently three pairs of slender ducts from the salivary glands. The
latter consist of very numerous small gland cells scattered diffusely
all through the preclitellal somites as far as the head. The cesophagus

102 - THE LEECHES OF MINNESOTA

is slender and distinctly differentiated from the stomach. At least six
pairs of well marked, long and slender gastric ceca are developed,
arising in somites XIV to XIX inclusive. Unfortunately they are
empty and shrunken and on account of the numerous gland cells which
fill the region difficult to see clearly, but they are certainly somewhat
branched and extend far toward the margins of the body. Those of
the last pair are long and reflected and extend as far as XXII,
lateral branches arising in each intervening somite in the characteristic
glossiphonid fashion. The intestine is a narrow tube which gradually
tapers to the anus and shows the differentiations usual in the higher
glossiphonids, including four pairs of prominent slender caca which
arise in somites XX to XXII and lie dorsad of the last pair of gastric
ceca. The first two are bent forward, enlarged at the end and some-
what subdivided, the third is bent backward and slightly lobulated and
the last is simple and directed rather strongly caudad from its origin.
The anus is situated at the posterior margin of XXVII, in this case
within the limits of that somite.

Very little of value can be made of the internal genital organs.
The testes are not certainly discernible. There is a pair of short wide
sperm sacs crowded with spermatozoa extending from the posterior
limit of somite XIII to a point just abreast of the male bursa, where
they pass into the narrower ejaculatory ducts which curve around the
anterior face of the bursa toward the median plane and then bend dor-
sad and caudad to the summits of the prominent nearly spherical
prostate.cornua. The latter open on each side into the dorsum of the
small bursa. The ovaries are enlarged pyriform bodies which lie
rather widely separated just caudad of the sperm sacs; from their
anterior enlarged ends narrow oriducts pass mesiad and _ slightly
cephalad to the female orifice. The external genital orifices are sit-
uated in the positions usual in the higher Glossiphonide, the male
at XI/XIJ, the female approximately at XII a2/a3. Nephridiopores
are quite easily distinguishable on the post-clitellal complete somites
just anterior to the sensillze line on annulus b3 and well mesiad of
the margins.

According to the label the Minnesota specimen was colored green
during life. It was pumped from the bottom of Lake Pepin. Nothing
is known of the habits of this leech.

THE LEECHES OF MINNESOTA 103

Genus Piscicola Blainville.

Size small; form slender and elongated, terete or subterete. Both
suckers large and- explanate, the posterior usually deeply cupped.
Complete somites of 12-14 very short tertiary annuli. Sensille and
-cutaneous papille very inconspicuous or absent. Eyes one or two
pairs widely separated on base of “head”. Atrium simple and in-
testinal ceca nearly completely coalesced. Parasitic on fishes, but
often found free.

Piscicola punctata (Verrill).
(Plate IIT, figs. 21, 22

Ichthyobdella punctata Verrill (1871)

Description—The usual size of this species is from 15 to 25 mm.
long and 2 to 3 mm. in greatest diameter, but the largest examples
are capable of extending to a greater length. In extension the body
is circular in cross section and very slender, widest at the beginning
of the posterior third. When contracted the distinction between
anterior and posterior regions of the body is much emphasized and
the latter becomes distinctly flattened. Although it has the form
characteristic of the genus the head is much smaller than in the well
known P. geometra.

Only one pair of eyes has been detected in a large number of
specimens which have been received from various localities. These
have conspicuous pigment cups situated in somite four and conse-
quently correspond to the posterior eyes of P. geometra which they
resemble also in the fact that they look caudad instead of cephalad
‘as do the first pair in that species. The smaller posterior pair de-
scribed by Verrill I have been unable to find either in entire mounts
or in sections and it is possible that some of the conspicuous pigment
cells which are scattered through the head may have simulated eyes in
his living specimens.

During life the posterior sucker is widely expanded and hemi-
spherical, but in preserved specimens it is always much contracted and
directed caudad. Just anterior to it is the minute anus among a group
of small wrinkled annuli.

The genital region (clitellum) is more or less distinctly limited by
anterior and posterior constrictions at the furrows IX/X and
XII/XIII respectively. In contraction XII may be more or less re-
tracted within the anterior border of XIII and all three of the somites

104 THE LEECHES OF MINNESOTA

of this region are of simpler structure than the typical complete ones
adjoining. Clitellar glands are greatly developed and form a thick
layer just within the longitudinal muscle layer and extending from the
clitellum nearly to the anus. They are arranged in four longitudinal
bands on each side leaving narrow neural, median dorsal, and lateral
spaces clear. The latter are occupied by the lateral vessels which ex-
hibit metameric enlargements in the somites of the posterior region.

Ten pairs of large nephridiopores are present on the latero-ventral
region of somites XIV to XXIII inclusive. They lie in annulus c6.
No especially metameric sensilla have been certainly distinguished but
numerous small sense organs arranged in transverse rows in many
of the annuli are present.

Owing perhaps to the different methods by which my material
has been prepared the annulation varies in a manner which, combined
with its complexity, is very confusing, and a complete analysis has
not been reached. Figure 21 Plate III exhibits a case which approxi-
mates the most frequently occurring condition, together with the in-
terpretation of somite limits which has been based upon a study of
the annuli themselves, the nephridiopores, nerve ganglia and partially
of the peripheral nerves.

Complete somites have the full number of tertiary annuli (cr to
c12) developed and in many one or two of these, usually in the
cephalic third of the somite, are divided into two, making in the latter
case fourteen annuli; but it is in connection with this feature and the
simpler somites at the ends of the body that the variability occurs.

Unlike Actinobdella the mouth is situated far back in the oral
sucker at III/IV or possibly within the limits of IV. The rather short
proboscis ends in VIII where it receives the several ducts of the
diffuse salivary glands occupying the pre-clitellial region. The
stomach is moniliform, constricted into six spheroid chambers occupy-
ing somites XIV to XIX inclusive and entirely without lateral czeca.
The last one passes into a long capacious unpaired cecum which
shows no apparent traces of its dual origin and extends with slight
sacculations to a point immediately beneath the anus. The stomach
and cecum, as might be expected, have a precisely similar histological
structure and both have a green color owing to the presence of numer-
cus branched pigment cells in their walls. The intestine arises from
the dorsum of the last gastric chamber in XIX by a constricted open-
ing and lies dorsad of the cecum throughout its length. At its com-
mencement it bears a pair of short wide pouches which project for-

THE LEECHES OF MINNESOTA 105

ward. About its middle is a constriction and caudad of this an en-
largement bearing another pair of ceca. Smaller ceca may occur
between.

There are but five pairs of testes alternating with the gastric
sacculations. Very delicate vasa efferentia start at the dorso-mesial
side of the testes and then pass forward and outward among the ventral
clitellar glands to the vas deferens, a very delicate tube resting on the
ventral body walls. Passing ganglion XIV the vas deferens becomes
larger and its course wavy and just in front of ganglion XIII expands
into a short, wide sperm sac which is looped caudad and, after a con-
striction passes into a ductus ejaculatoruis of half its diameter and
twice its length. The latter becomes very narrow as it enters the
thick loose layer of unicellular glands which conceal the median ever-
sible bursa from view. The male orifice is located at XI/XII. The
paired ovaries are large elongated simple sacs which even in their
much folded condition reach as far caudad as somite XVI. They
open at or about XII a2/a3.

Verrill describes the colors during life as ‘‘translucent greenish,
with a pale median dorsal line and with minute black specks arranged
in transverse bands; along each side are eight light spots, alternating
with the dark punctate bands.” The black specks are branched pig-
ment cells which are scattered through the integument with singular
regularity. Large individuals become more opaque owing to the
great development of clitellar glands.

Habits—This is our commonest fresh water fish leech. It is com-
mon in the ponds and lakes of the northern states and the Mississippi
Valley and is especially abundant along the Ohio shore of Lake Erie.
It lives upon the exterior of the body of various species of small fishes
feeding upon the mucous which covers the surface as well as upon
their blood. It appears to be in no way injurious to its hosts. Many
examples may also be found living among water plants to the stems
of which there is good reason to believe its stalked cocoons are at-
tached.

Family Hirudinide.

Leeches mostly of large size, more or less elongated, with thick,
little depressed bodies. A well-developed zonary clitellum in most
species during the breeding season. Oral sucker forming lips sur-
rounding the large mouth; caudal sucker rather small or well de-
veloped, discoid. Complete somites usually of 5, rarely of 3 or 7, an-

106 THE LEECHES OF MINNESOTA

nuli. Eyes usually 5 pairs, forming a marginal arch on somites II to
VI. Metameric sense organs usually conspicuous colorless spots on the
neural annuli, 6-8 above and 4-6 below. Cutaneous papilla small or
absent. Mouth large, occupying entire oral sucker; pharynx not pro-
trusible, usually preceded by three compressed, muscular, toothed jaws,
one dorsal and two ventro-lateral, the former alone, or all three
sometimes absent. Stomach with a single posterior pair of simple
ceca, or provided with one or two pairs of ceca in each segment; no
intestinal czeca. Genital pores variable, the male usually on XII, female
on XIII and usually separated by 5 annuli; associated copulatory
glands may be present. Testes sacs usually 10 pairs belonging to
somites XIV-XXIII. Genital ducts complex, the male terminating in
an unpaired atrium with prostate gland and a usually filiform penis.
Ovisacs 1 pair, small pyriform, opening into an unpaired oviduct
terminating in a long vagina. Copulation occurs, during which the
penis of one individual implants spermatophores in the vagina of the
other. Eggs enclosed in vesicular or spongy chitinoid cocoons de-
posited in damp earth. Fresh water or more rarely terrestrial leeches.
which are voracious blood suckers or predatory destroyers of weaker
invertebrates. Mostly active swimmers.

Genus Macrobdella Verrill.

Size large. Dorsum marked by metameric red and black spots.
Jaws prominent each bearing numerous small teeth in a single series;
gastric ceca very spacious, two pairs to each somite from X to XVIII.
Genital orifices separated by from 2% to 5 rings, followed by the
two pairs of copulatory gland pores, which form a quadrate figure
opening in the furrows XIII/XIV and XIV br/b2; penis short and
conical; atrium and vagina both short, globoid. Active blood-suckers,
attacking vertebrates.

Macrobdella decora (Say) Verrill.
(Plate IV, figs. 24, 25; Plate V, fig. 38)

Hirudo decora Say (1824)
Hirudo decora Leidy (1868)
Macrebdella decora Verrill (1872)

Description. Jfacrobdella decora, the American medicinal leech,
reaches a length of eight to ten inches and a breadth of three-quarters
of an inch, but the examples most frequently met with are much
smaller than this, while the largest may occassionally exceed this size.

THE LEECHES OF MINNESOTA 107

The body is depressed throughout, more so than in any native species
of the family and the margins are sharp. During life, however, the
body is very soft and assumes a great variety of attitudes and shapes.

The oral sucker is a powerful organ provided with a rather wide
tnsegmented and very mobile border which very materially tmcreases
its extent. Anteriorly a distinct median emargination corresponds
with a deep ventral sulcus which divides the upper lip and is flanked
by a pair of somewhat shallower sulci. The upper lip can be folded
into the buccal chamber and almost concealed by the lateral lobes
which close beneath it. As usual in the family there are five pairs
of eyes, larger in this species than in the species of Hemopis. Their
arrangement is sufficiently indicated in the figure. The posterior
sucker is large, broadly attached and circular.

When fully developed the clitellum is firm and thick and extends
over eighteen annuli, from X b5 to XIV b2, but it is seldom so well
marked nor. so extensive. In the ordinary condition the male pore
appears as an. opening of considerable size in the furrow XI/XII,
into which the surrounding regosities converge. When these inflected
parts are everted they form a more or less prominent conical penis
which reaches a length of about three millimeters when fully pro-
truded. In this condition it is supported almost entirely on annulus
XII br which has greatly encroached on the preceeding annulus in
the middle region. The female orifice is a small opening with rugous
margins situated at XII/XIII or XIII br.

Very characteristic of the genus are the copulatory glands, which
form conspicuous masses occupying a large part of the middle region
of the floor of somites XIII and XIV. Their external openings are
four in number, arranged at the four angles of a nearly square figure,
the first pair opening in the furrow XIII/XIV and the second in the
furrow line XIV b1/b2. Surrounding each of the pores is a slightly
tumid region extending over the contiguous halves of the two annuli
between which the pore lies. When fully developed the four tumo-
sities are separated only by shallow furrows and together form a con-
Spicuous rugous quadrate area extending over the posterior half of
XIII 66, the anterior half of XIV b2 and all of the intervening an-
nulus. Jongitudinal and transverse diametral furrows divide it into
quarters.

The surface of the body of this species is quite smooth and free
from papill, although more or less roughened in some preparations
by the scattered sense organs. Nephridiopores and sensillze have the

108 THE LEECHES OF MINNESOTA

customary disposition. The latter can be very favorably studied on
the dorsal surface but are difficult to distinguish on the generally light
background of the ventral surface.

Somites I, I] and III are uniannulate, IV and V biannulate, and
VI triannulate on the dorsal side. Somites VII and VIII are re-
spectively triannulate and quadriannulate but VII a? and VIII ar are
enlarged and quite distinctly subdivided dorsally. Then follow sixteen
complete quinquiannulate somites, IX to XXIV inclusive, in which
the neural annulus is typically shorter than any of the others. At
the posterior end XXY is again quadriannulate, there being only one
post-neural annulus (a3) instead of two, XXVI is biannulate with az
more or less distinctly separated from a2. The large anus cuts into
the posterior margin of XXVII.

As in all of the predatory leeches of this family the mouth is of
large size and may be considered to be coextensive with the opening
of the oral sucker. The three jaws exhibit the usual relations, but
their form is characteristic of the species among the leeches of the
northern United States. They are about twice as long as high and
each bears about sixty-five fine conical, slightly .retrorse, uniserial
teeth. A very short pharynx with several longitudinal folds reaches
to about IX, within which segment it is succeeded by a still shorter
cesophagus which can scarcely be distinguished from the stomach, as
sacculations begin to be evident immediately. From X to XVIII in-
clusive each somite includes two pairs of gastric ceeca of which those
from XIII backward are of large size. The last pair, which originate
from the stomach in the anterior part of somite XIX, are of very great
extent, reaching XXIV or XXV, and bear two wide lateral branches
in each of the intervening somites. The straight narrow intestine pre-
sents no noteworthy features.

Ten pairs of testes are situated, intermetamerically, as most usual
in the leeches, at XIII/XIV to XXII/XXIII inclusive. The vasa
deferentia are enveloped in crowded unicellular glands and follow
somewhat sinuous courses. In somite XI they lose their glandular
covering and appear as delicate ducts, which opposite to ganglion XI
pass abruptly into the anterior end of the compact massive epididymes.
From the. posterior end of the latter wide somewhat folded ducti
ejaculatorii lead to the terminal organ. Just before entering the outer
glandular covering of the bursa or atrium the ducti become constricted
and then rise as a pair of slightly enlarged sacs which open into the
summit of the invaginated bursa to which they stand in the relation

THE LEECHES OF. MINNESOTA 109

of cornua. This median organ which evaginates to form the penis is
in its retracted condition spherical or inverted pyriform and has thick
muscular and glandular coats.

The colors during life are very showy. Above the ground varies
from a light sage green to a rich olive green with obscure longitudinal
stripes or short lines in the median areas. The median metameric
spots are cadmium orange or light red and the marginal spots black.
The ventral surface is a rich orange sometimes plain, sometimes spot-
ted with black. The colors fade very quickly in alcohol.

Habits—This species, the native American medicinal leech, ap-
proaches closer to the European Hirudo medicinalis, both in structure
and habits, than any other indigenous American species, and, when
the use of leeches for blood-letting was more general than now, was
largely employed by physicians. To a limited extent it is still gathered
in the swamps below Philadelphia and sold for this purpose. It 1s
widely distributed throughout the northern half of the United States
and in Canada and is an inhabitant of standing water rather than of
streams or rapidly flowing rivers. Great numbers often occur in small
ponds and lakes. Altogether it is the best known of the American
leeches and has been frequently written about since its discovery by
Say in 1824, but its exterior has not hitherto been figured although
Whitman has published drawings of the annulation of a closely allied
species.

Macrobdella is more strictly aquatic than the species of Hemopis
and probably does not leave the water voluntarily though it will live
for weeks buried in the mud left by the drying up of small ponds and
pools in dry summers. It is an active predacious creature and swims
actively at the surface at night or during the day if attracted by the
presence of food. It is well known to the American boy who fre-
quently comes from his plunge in the brickyard or meadow pond with
several of these leeches firmly attached to his skin, an experience so
frequent as to have gained for it the general name of blood-sucker.

It also attacks cattle which enter its domain to drink or cool but
its natural food is the blood of fishes, frogs and turtles which it attacks
and frequently kills. Small aquatic annelids in large numbers and
occasionally larval insects have been found in the stomach. In the
spring frogs eggs are devoured in large numbers, the ege’s being sucked
out after the gelatinous envelopes have been cut by the sharp saw-
like teeth of the leech.

In coitus the leeches cohere by means of the secretion of the copu-

110 THE LEECHES OF MINNESOTA

latory glands at the same time coiling somewhat about each other.
Cocoons are formed and deposited in the mud by the side of the pond,
and there left to hatch.

Genus Hemopis Savigny.

Size large to very large. Dorsum plain or marked by a median
stripe or by irregular non-metameric spots and blotches. Jaws small
and bearing a few large double teeth, or absent; one pair of posterior
gastric ceca only. Genital pores separated by five rings; no copulatory
glands; penis filiform; atrium and vagina both much elongated. Food
chiefly worms, insect larvae, etc., not normally blood-suckers.

Hzmopis marmoratis (Say) Moore.
(Plate TVs fig..32)

Hirudo marmorata Say (1824)
Aulastomum lacustre Leidy (1868)
Haemopis marmoratis Moore (1901).

Description—The size is medium, seldom exceeding six inches in
length and one-third of an inch in diameter, though larger specimens
are sometimes met with. Owing to the extensive development of
botryoidal tissue the body is exceedingly soft and limp and conse-
quently varies greatly in shape. Compared with the other species of
Hemopis described in this paper the form is rounder and less flattened
than they, except in swimming, when this specics also becomes flat-
tened. ;

Although the anterior sucker is relatively large and the lips broad,
the unsegmented margin is very narrow and there are no distinct in-
ferior sulci as in Macrobdella. Of the five pairs of eyes the first three
pairs are conspicuous and are arranged in a regular arc on the first
three annuli; the fourth and fifth are on the sixth and ninth annuli
respectively and are much more obscure, being deeply placed. All
of the eyes are smaller than the corresponding ones of Macrobdella.
In mature individuals the clitellum is very distinct and equally well
developed dorsally and ventrally and often is the widest region of
the body. It extends over fifteen annuli, from X 05 to XIII a2 in-
clusive. The posterior sucker is relatively small, circular and broadly
attached; about one-third of it projects beyond the body posteriorly
and its anterior margin reaches to XXV a2.

Somite I can seldom be distinguished from II which again is im-
perfectly separated from III; IV is biannulate, as is V also, but the

THE LEE GHES OFeMiINNES ODA: 1G

latter is more fully elaborated dorsally. On the typically biannulate
somite VI, az and a2 are more or less separated by a furrow confined
to more or less of the middle dorsal region. Somite VII is fully
triannulate but is peculiar in the large size of a3, which, moreover, may
exhibit a faint dividing furrow; VIII is quadriannulate and ar re-
sembles VII a3 in being enlarged and partly subdivided. There are
fifteen (IX to XXIII) quinquiannulate somites, in which all of the
annuli are approximately equal. Somite XXIV is quadriannulate and
sometimes the last annulus (a3) is faintly subdivided, usually on the
ventral surface; XXV is triannulate, but ar, which is normally of
larger size than the remaining annuli, is subject to much variation.

The following two somites, XXVI and XXVII, are variable and

difficult to interpret, but the uniannulate condition is probably the

most usual. .

! Just anterior to the jaws and separating them from the buccal
is a slight circular sulcus and fold. The jaws are low and
acd, not at all compressed on the free edge. As usual they may

be retracted into little pockets so that the entire toothbearing surface
is concealed. Each jaw bears a double file of large, coarse teeth ar-
ranged in from twelve to sixteen pairs. The pharynx reaches to X and
has from nine to twelve or more longitudinal folds, three of which
unite into a strong ridge behind each jaw. The long narrow stomach
reaches to XIX, and is provided along its entire length with numerous
small pockets ; at its posterior end a pair of large ceca arise and reach
caudad to XXII or XXIII. The intestine is also straight and bears
two or three pairs of quite large, short, globular czeca which lie dorsad
of the large posterior gastric ceca. The anus is very large.

The customary ten pairs of testes are present in the anterior
end of somites XIV to XXIII each reaching into the preceding somite.
The collecting portion of the vasa efferenta and vas deferens are es-
sentially similar to those of Macrobdella. The epididymis is a rather
narrow tube, much convoluted, rather open and not at all massive.
The epididymis opens into the small fusiform sperm sac in the
posterior part of XIII and the latter is continued as the ductus ejacu-
latorius. This canal reaches forward to the level of the male pore
and then bends back to join the closed end of the atrium, sometimes
the right, sometimes the left one, passing beneath the nerve cord. The
atrium or penis sheath is very long and slender, with a sharp bend
at ganglion XVII, from which point one limb reaches to the male
pore, the other to the anterior end of somite X\; the ratio of the

112 THE LEECHES OF MINNESOTA

short and long limb is about as one to two and one-third. The penis
is a slender filiform organ with a slightly bulbous extremity and is
frequently extruded to a length of three times the width of the leeches
body. ‘The male orifice is on the anterior part of XI D6 or, less fre-
quently, between this and the preceeding annulus.

The paired ovaries are situated in the posterior part of XIV dor-
sad of the nerve cord and in contact with the second pair of testes.
There is a large albumen gland and a long narrow common oviduct
which opens into the narrow anterior end of the pyriform ovisac lying
in somite XVI. From the posterior end of the latter a long, slender,
much convoluted vagina reaches to the female orifice at XII b6 or XII
b5/b0.

Hemopis marmoratis includes many color varieties. The ground
is usually some shade of green, olive green or greenish brown, some-
times nearly plain, sometimes remotely spotted, but usually thickly
and confluently blotched with irregular or intermixed spots of lighter
grays and darker browns or black. The lighter kinds tend to pre-
dominate on the ventral side, from which the darker pigments may be
altogether absent. The darker markings are sometimes so close on
the dorsal surface as to produce an almost black color.

Habits—The horse leech, as this species is called, is found in
practically all parts of North America, where it has a known wider
range than any of its near allies. It is semi-aquatic, living in the
mud by the sides of ponds, pools, and lakes rather than actually in
the water, although it of course moves freely about in the water and
is often found in the mud at the bottom. Along tidal rivers the species
is most abundant beneath stones on the flats exposed at low water
where it lives with several species of true earthworms. At times it
wanders some distance away from the waters edge, burrowing in
the soil in search of the earthworms on which it feeds; but it is not
terrestrial in the sense in which H. lateralis is, never leaving, so far
as has been observed, the near vicinity of water. Besides earthworms,
various kinds of aquatic insects and their larvae, aquatic oligochaetes,
gastropods and pelecypods are pursued and eaten and large quantities
of mud containing organic matter are swallowed. The species is also,
like many other leeches, a scavenger and great numbers will collect
on the body of a recently killed animal thrown into their haunts.
Blood is also taken when the opportunity is afforded of attaching it-
self to drinking cattle or the legs of boys wading in its haunts. It
would be interesting to know if it ever enters the pharynx of cattle,

THE LEECHES OF MINNESOTA 113

as is well known to be the habit of the Limmnatis so common in some
of the countries bordering on the Mediterranean.

Hemopis lateralis (Say) Moore.
(Plate III, fig. 23)

Hirudo lateralis Say (1824).

2 Macrobdella valdiviana et gigas Philippi (1872)
Semicolex terrestris Forbes (1890)

Hemopis lateralis Moore (1901)

Although there are some minor differences I am

Description
unable to separate the aquatic leech originally described by Say from
specimens procured in Minnesota from the interesting terrestrial form
which Forbes has described and which was found by him in consider-
able numbers in garden soil in Illinois. So far only the aquatic variety
has been found in Minnesota and was represented in the Survey
collections by two living examples which unfortunately escaped from
me and were lost.

Compared with the terrestrial variety, of which even Prof. Forbes’
contracted alcoholic specimens reach a length of eight inches, a large
number of the aquatic form, chiefly from Ohio and Maryland, average
much smaller, about five inches long and one-half inch wide being the
usual size. This species is much more slender than //. marmoratis
and the greatest width lies farther caudad. The body is rather more
muscular and as a consequence firmer, but during life exhibits the
same variety of shapes and postures.

The mouth is somewhat smaller and the oral sucker narrower
than is H. marmoratis, while a further slight distinction is found in
the better developed longitudinal grooves beneath the lips of this
species. The eyes have the same number and position as in the
species last described.

In the few cases in which a clitellum has been observed it differs
in no respect from H. marmoratis. Although not differing in any way
from the typical arrangement in the family, the seventeen pairs of
nephridropores on the posterior margin of b2 of somites VIII to
XXIV inclusive are unusually distinct and lie just behind a sort of
slight spout-like projection. The posterior sucker is noticeably small.

Throughout the entire length of the body the annulation is very
distinct, and at the margins most of the annuli are rather sharply
angulated. In most respects the somites are constituted just as in

IT4 THE LEECHES OF MINNESOTA

H. marmoratis but the following features are diagnostic: Somite VII
is fully quadriannulate and VIII quinquiannulate, owing to the com-
plete subdivision of VII a3 and VIII ar each into two annuli; as a
consequence this species has two more annuli in the anterior region;
VI a3 and VII az are always relatively wider and may exhibit an
incipient furrow ; on the complete somites the annuli are not equal but
bear the following relation :—a2<bi=b2<b5=b6, except at the
posterior end of the series; finally XXVI and XXVII are typically
biannulate.

Including the rudimentary denticles at the posterior end each jaw
bears from twenty to twenty-five pairs of teeth, of smaller size and
more irregular form than in H. marmoratis. In other respects the
digestive organs are essentially similar in the two species.

The sperm sacs and epididymes do not reach beyond ganglion XI
anteriorly, or ganglion XII posteriorly; the latter are massive and
compact and partly envelope the sperm sacs to which they are closely
moulded. The posterior bend of the atrium is at ganglion XIV and
the relative length of the two limbs is as one to one and seven-tenths
in three examples measured. Although the genital pores are in the
homologous annulus they lie two annuli farther from the mouth than
in H. marmoratis. The ovaries are always within somite XII, and
the vagina never extends posterior to ganglion XIV.

Forbes thus describes the colors of living examples of the ter-
restrial variety—‘“sooty drab, varying to plumbeous black, somewhat
lighter beneath, uniform in tint and quite without spots or mottlings
of any sort. A darker median longitudinal stripe, very conspicuous
and well defined, is almost invariably present; a paler marginal stripe
often approaching buff, little less constantly so; and a ventral sub-
marginal stripe of the same color as the median dorsal one likewise
quite frequent.” The ground color of the aquatic variety is similar,
but while the dorsal black stripe is less constant it may be very con-
spicuous; more frequently it is faint and obscure, broken into small
spots or totally wanting. A few small dark spots are sometimes scat-
tered over the dorsum. Sensilla are much more distinct in the aquatic
than in the terrestrial variety; indeed Forbes failed to find them in the
living specimens of the latter.

Habits—In habitat, food, movements, resting attitudes etc. the
aquatic variety is essentially like H. marmoratis. It is capable of a
greater degree of extension and appears to be a more active swimmer
than that species. Two examples sent to me by Prof. Nachrtieb and

THE LEECHES OF MINNESOTA 115

the only ones included in his collections were placed in an aquarium
with H. grandis. One night the cover was accidentally left displaced
and on my arrival the following morning both were gone, but none of
the other species were missing. A shining track of dried mucous on
the polished floor showed the course of their wanderings. One quickly
disappeared beneath a wall case. The other was tracked for a meas-
ured distance of more than fifteen yards, when it too disappeared be-
neath the wash-board. Neither was recovered, but the circumstance
is mentioned as showing the tendency of this species to wander and its
ability to live in a perfectly dry situation, and as further confirmation
of my opinion of the identity of this with the land leech of Illinois.
Under the same circumstances Hemopis marmoratis or Erpobdella
punctata would have quickly died before having crawled nearly so
great a distance, as I know from experience. Concerning the ter-
restrial form Prof. Forbes writes of having obtained fifty-six speci-
mens, all from the earth in central Illinois and some of them half a
mile or more from the nearest water, while none occurred in the
course of a large amount of aquatic work done in the same regions
during the same period. Its only known food is earthworms which
it swallows entire. From the fact that his specimens were all obtained
from March to June, Prof. Forbes suggests that it is probable that this
species penetrates the soil to considerable depths during the midsummer
draughts. So far as I know the terrestrial form has been taken by no
one else in this country, but a very large terrestrial leech found by
Philippi in Chile is indistinguishable in the description and excellent
figure from Forbes species.

Hzmopis plumbeus sp. noy.
GRlatewVihigs.295 30,2310)
? Hirudo lateralis Say (1824) in part.

Description—Though resembling H. lateralis quite closely in color
this hitherto unnamed form stands much nearer to H. grandis, to be
next described, in respect to both internal and external structure. The
features in which it differs from the latter are rather slight but have
proved quite constant in all of the specimens examined. Probably this
species does not equal H. grandis in size, the available specimens vary-
ing between two and six inches in length. The form is heavy like that
species, and the oral sucker larger and lips much broader. A rather
wider unsegmented rim borders the sucker. Except that they are rather
larger the eyes are like those of H. grandis in structure and arrange-

116 THE LEECHES OF MINNESOTA

ment. The sensille, nephridiopores and anus present no distinctive
features. None of the specimens examined has the clitellum de-
veloped.

The annulation is essentially like that of 7. grandis but a few
differences occur, which may disappear when a larger series of speci-
mens comes to be compared. The furrows are well marked but pre-
sent little of that zigzag character and secondary wrinkling which is so-
conspicuous in the larger species. This difference is very marked in
specimens of the two species of equal size and preserved together, so
that it may prove not to be accidental. The furrow V az/a2 is quite
incipient and the annuli VII a3 and VIII az are relatively much
smaller and very much less distinctly subdivided than in H. grandis.

The mouth is very large and the ventral surface of the lip shows
no trace of longitudinal sulci. Jaws are absent and the capacious
pharynx bears twelve very low longitudinal folds. The remainder of
the alimentary canal appears to differ in no way from that of H.
grandis.

The external genital orifices are constantly in the middle of annuli
XI b6 and XII b6 respectively, while in H. grandis the male pore is
almost invariably at XI b5/b6 and the female in the anterior part of
XII b6. The penis is filiform and may protrude to a length of two and
one-half times the width of the body at the male orifice. It is in the
structure of the internal reproductive organs that the most evident
differences between this species and H. grandis are found. In fact
the resemblance is much closer to H. marmoratis in respect to these
crgans. The atrium extends caudad far beyond the vagina to the
neighborhood of ganglion XVI where the usual sharp bend occurs.
The short limb is about one-half as long as the long one. Relatively
small sperm sacs, which are not more than one-fourth or one-fifth of
the length of the atrium, lie far forward in the region of the male
orifice. The coils of the epididymes lie chiefly by the side of the sperm
sacs and not heaped up at their caudal end as in H. grandis. Unlike
any other species of the genus described in this paper the vagina is
very much shorter than the atrium, reaching only to the caudal end
of the somite XIV. The common oviduct lies on the dorsal side of
the vagina; the albumen gland is large and nearly spherical and the
ovaries are just in advance of the female pore.

The color is a remarkably uniform leaden or slaty gray, usually
purer and sometimes darker below, and often showing a slight olive
or yellowish tinge above. Along the entire lateral margins from the

THE LEECHES OF MINNESOTA 117

caudal sucker to the lips is a broad, dull but conspicuous rufous or
orange band which broadens and encroaches on the dorsal surface as
it approaches close to the head, but contracts again on the lip to a nar-
row marginal line. The ventral margin of this band is, owing to the pur-
er ground color below, more sharply defined. Small irregular spots of
black are scattered more or less remotely over the dorsum, being usu-
ally most numerous toward the margins and ends of the body, especial-
ly in the specimen figured. Sometimes they are almost absent and
are never numerous. Except for a few along the lateral rufous band
the ventral surface is free from spots. The caudal sucker is of the
ground color both above and below, with a narrow rufous border.

Nothing distinctive concerning the habits of this leech is known
to me and I have seen no examples except those in this collection from
northern Minnesota.

It seems very probable that the presence of spots which Say
attributes to his H. lateralis may have applied to this species rather
than the one which is represented by Say’s supposed type. The spots
are much more conspicuous and constant in this than in that species
and as the coloring is otherwise almost identical and both species
occur in the precise region from which his types came Say might
easily have confused them.

Hemopis grandis (Verrill).
(Plate IV, figs. 26, 27, 28; Plate Ve hgy SA)

Semiscolex grandis Verrill (1874).

Description—As Prof. Verrill indicated in his original description
this is a monster among American leeches, exceeding the North Amer-
ican representatives of the terrestrial variety of H. lateralis and at
least equaling the larger representatives of that species which Philippi
has described from Chile under the names of Macrobdella valdiwiana
and M. gigas. Living examples not infrequently exceed a foot in
length and specimens of fifteen ore even eighteen inches have been
reported from the lakes of Minnesota. However, this is an unusual
size and smaller individuals having a length of from five to eight
inches are much more common.

The body is very robust and heavy posteriorly, but rather slender
anterior to the clitellum. While seldom much depressed the body does
not assume the quite rounded form frequent in H. marmoratis, which
some varieties of this leech closely resemble in general aspect. In

118 THE LEECHES OF MINNESOTA

life the body is soft and limp and possesses a great facility for con-
traction and elongation and other changes of form.

While large, the mouth is more contracted than in H. plwimbeus
and the lip narrower and more prolonged. The five pairs of eyes have
the arrangement usual in the family; they are all of relatively small
size and the fourth and fifth pairs quite inconspicuous.

The clitellum is a thick and prominent glandular girdle extending
over fifteen annuli from X b5 to XIII b2, often rather within the latter
but apparently never as far as its middle. The female orifice is similar
but drawn out laterally to a slit-like form and usually well within an-
nulus XII b5, sometimes as far back as its middle or so far forward
as to lie in the furrow XII a2/b5.

Seventeen pairs of nephridiopores can be readily distinguished
on the posterior margins of the first annulus (az) of VIII and the
second annulus’ (b2) of somites IX to XXIV inclusive. They, to-
gether with the metameric sensilla, have the positions usual in the
genus and the marginal sensille show the same tendency to become
subdivided. There are no cutaneous papilla, the skin being smooth.
However, the short shallow wrinkles seen in many large leeches are
remarkably conspicuous in preserved specimens of this species and give
to the interannular furrows a peculiar zigzag course which is especially
pronounced toward the ends of the body. The usual non-metameric
sense organs are present in abundance and are especially numerous
on the lips. The annulation differs in no essential feature from that
already described for Haemopis marmoratis.

While retaining all of the characteristics of the genus the repro-
ductive organs differ considerably in the proportions of the several
regions of the complicated ducts from all of the other species found
in Minnesota. The epididymis is remarkably massive and lies chiefly
caudad of the corresponding sperm sac which is consequently not so
largely enclosed in its coils as in H. lateralis. The sperm sac is re-
markably large, being much wider than and about half as long as the
atrium when fully distended, as jn the specimen figured. Its anterior
end is just behind ganglion XII and tapers into the ductus ejaculatori-
us whichis noteworthy for its shortness. . In almost every instance the
atrium is doubled on itself at about the middle, so that the two limbs
are approximately equal and the blind glandular end is usually a little
anterior to the male pore. Either the right or left ductus ejaculatorius
may pass beneath the nerve cord.

The ovaries are situated in the anterior part of XIII immediately

THE LEECHES OF MINNESOTA 119

behind the female pore, and both may lie dorsad of the nerve cord or
ene pass beneath it. There is a large pyriform albumen gland, a short
common. oviduct and a relatively short, thick vagina.

A median and one or two pairs of lateral longitudinal furrows,
together with some less constant and minor ones, mark the ventral
surface of the lip. The transverse sulcus dividing the buccal chamber
from the pharynx is deeper than usual, which is perhaps correlated
with the entire absence of dentigerous jaws in this as in the last de-
scribed species. Although somewhat variable and irregular there are
typically about twelve prominent longitudinal pharyngeal folds. Nine
of these are in three groups of three each coalescing anteriorly at what
would be the position of the jaws in other species. Three, unusually
simple and frequently incomplete folds, alternate with these. The
stomach scarcely shows any indication of lateral pouches and the
posterior pair of ceca are remarkably short, scarcely one-half the
length of the intestine.

On the dorsal surface the ground color varies from tawny olive
through olive and olive green to oil green, the green colors being nearly
pure in some examples, especially in those which are least spotted. In
others they are impure from the suffusion of brown or dusky pigments
in the deeper tissues, in extreme cases imparting to the entire dorsum
a brownish hue. The lighter greens appear most frequently toward
the anterior end and on the caudal sucker, but in many examples these
regions become dusky. Frequently a marginal rufous or orange stripe
is present, especially toward the posterior end, but it is seldom or
never so clearly defined as in H. plumbeus. The ventral surface is
gray, yellowish or light brown but always paler than the dorsum.

There is a great range in the degree of maculation which, as com-
pared with H. marmoratis, is characterized by a greater boldness and
distinctness in this species. Perhaps the most typical condition is that
in which the dorsum of each complete somite is marked by eight or ten
irregular but somewhat quadrate black spots, most of which are con-
fined to the limits of one annulus, but a few, especially toward the
margins, are larger and more irregular. In other cases the spots are
much more numerous and confluent so that the real ground color ap-
pears as lighter areas on the dark field. Still others are as nearly free
from spots as some examples of H. plumbeus. The ventral surface
bears fewer spots than the dorsal and not infrequently is quite immacu-
late.

120 THE LEECHES OF MINNESOTA

Habits—This great leech is found on the shores of the Great
Lakes and abounds in the numerous lakes and ponds of Wisconsin,
Minnesota and Michigan. Eastwardly it extends its range through
New York into New England but is rare in the Middle States and I
have had but little opportunity to study its habits under natural con-
ditions.

It appears to live chiefly about the borders of the bodies of water
which it affects, concealing itself beneath stones. According to Bar-
rows it secretes an unusual abundance of mucous and I suspect from
this fact and the large size of the nephridial bladders that it may upon
occasion leave the water. Stomach examinations show that its food
consists of earthworms and allied aquatic worms, smaller leeches,
particularly the nephelids, snails, insect larvae and organic mud. In
captivity several individuals fed voraciously on earthworms but could
not be induced to attack fishes, frogs or turtles even when the skin was
abraded so that the blood flowed, from which behavior it would appear
that the accounts of this species habitually attacking -fish require to be
verified.

Family Herpobdellide.

Leeches of mostly moderate size and slender elongated form, usu-
ally terete anteriorly, often much depressed posteriorly. Clitellum as
in Hirudinide. Oral sucker small, forming lips; caudal sucker also
small, discoid. Complete somites fundamentally of five rings, but one
or more often subdivided, forming six to eleven rings. Eyes usually
four pairs, two pairs on somite II often coalesced, two pairs of smaller
size on IV; but sometimes eyeless. Cutaneous sense organs and papil-
lz numerous, not obviously metameric. Mouth and pharynx as in
Hirudinide, but the latter with three longitudinal muscular ridges and
no jaws. Stomach and intestine straight, simple and without divertic-
ula. Genital orifices variable in position, the male usually on XII, the fe-
male on XIII. Testes sacs small and very numerous, extending through
about segments XVIII to XXIII. Sperm ducts very long and much
convoluted, paired until they empty by means. of the short prostate
cornua into the small median atrium. No protrusible penis. Ovisacs
long and slender as in Glossiphonide but each doubled on itself,
united only at the external orifice. Copulation takes place and
spermatophores are implanted on the iftegument. Eggs enclosed in
flat, pouch-like chitinoid cocoons fastened by one side to stones, sticks,
plants, etc. Fresh water predaceous leeches, feeding on insect larve,
worms, etc., occasionally suck the blood of vertebrates.

THE LEECHES OF MINNESOTA 121

Genus Erpobdella Blainville.

Size moderate ;, posterior region not greatly depressed. Sperm
duct forming a long loop (reaching to ganglion XI) anterior to atrium,
which is provided with a pair of simply curved horns. None of the five
annuli of complete segments distinctly enlarged and subdivided.

Erpobdelia punctata (Leidy) Moore.
( Plate PVs figs 32s)

Nephelis punctata Leidy (1870)
Nephelis lateralis Bristol (1898) in part.
Erpobdella punctata Moore (1901)

Description—The form is elongated with the sides nearly parallel,
tapering anteriorly to the clitellum but very little at the posterior end.
Anteriorly it becomes almost circular in section and posteriorly, al-
though margins are sharp and prominent, is little depressed and
widened. The size is large for the family, reaching a length of about
five inches. The body is very firm, hard and muscular.

The oral sucker 1s very small, being little more than a short lip
overhanging the nearly terminal mouth. Normally there are three
pairs of eyes, the first decidedly the largest and situated close together
on somite II and directed forward; the others more widely separated
on the sides of 1V and looking somewhat backward. The clitellum
is frequently seen in full development, in which condition it is a wide,
thick complete girdle covering the fifteen annuli from X b5 to XIII a2
inclusive. The male pore is a rather conspicuous opening at XII
b2/a2, the female a much smaller one at XII 05/b6 or two annuli
farther caudad.

Somites I, II and III are uniannulate; IV and V are biannulate,
VI is triannulate, VII quadriannulate; and VIII to XXIV inclusive,
or seventeen somites, are quinquiannulate. At the posterior end somite
XXV is quadriannulate, though the last annulus (a3) may be more
or less distinctly subdivided on the dorsum; XXVI is either biannulate
or triannulate and X XVII is usually uniannulate.

In the complete somites the annuli are of approximately equal
length and D6 is not obviously enlarged or more completely subdivided
than the others. Numerous small cutaneous papillz bearing sense
crgans appear arranged in an irregular transverse row on each an-'
nulus. They are largest dorsally and on the neural annulus. The
annuli of the simpler somites frequéntly exhibit two such rows, indicat-
ing their composite character.

122 THE LEECHES OF MINNESOTA

The testes are numerous, about fifty to sixty on each side of
somites XVIII to XXIV, mostly with separate vasa efferentia. The
enlarged and much convoluted epididymis or sperm sac reaches from
XVIII to XIV. There is a long pre-atrial loop to the ejaculatory
duct reaching to ganglion XI. The atrium consists of a small eversible
bursa and a pair of elongated semi-erect, curved prostate cornua, the
bases of which are enveloped by a thick layer of prostate glands. The
ovaries are elongated sacs each doubled on itself and reaching for
a variable distance through the ventral sinus.

In this species the color varies extremely. Young individuals us-
ually contain little or no pigment, permitting the red color of the blood
to appear through the translucent tissues. The adult pigmentation is
assumed gradually with increase in age and size. When full grown
the ground color may be plumbeous, slate color, brownish gray, olive
brown, fuscous, light brown or chocolate, always somewhat lighter
ventrally and in the furrows and enlivened on the margins by the red
tint of the lateral blood vessel. Sometimes a beautiful golden green
hue overspreads the entire dorsum. The browns are most usual and
may be plain or more usually more or less marked with irregular black
spots with light centers, arranged in two or four longitudinal lines
leaving the middle of the back and the margins clear.

Habits—Within the area of its distribution, which is extensive,
this leech occurs under a great variety of conditions. Almost every
spring, brook and river, ditch, pond and lake, no matter how pure and
cold or how warm and foul, is its home. And in most situations it
is by far the most common species of leech present, exceeding in num-
bers even the omnipresent Glossiphonia stagnalis. The size varies
greatly with the extent of the body of water and the richness of the
food supply. Small clear brooks and ditches almost invariably yield
only small individuals, while by far the largest individuals which I
have seen come from large rivers and ponds and the Great Lakes.
Bristol has pointed out that in any particular pond they congregate
on the shore which receives the richest food supply and my own ex-
perience substantiates this.

Like many other species of leeches this one conceals itself during
the day beneath stones, logs, leaves or whatever happens to be con-
_venient for the purpose, but leaves its shelter at night and searches
actively for food. In aquaria the rhythmic respiratory movement,
which takes place while either both or only the posterior sucker is at-
tached, may be frequently observed. It is so muscular and the body so

THE LEECHES OF MINNESOTA 123

hard, wiry and slippery that it is really quite difficult to hold a living
cne between the fingers. When picked up it struggles and writhes
violently and when disturbed creeps rapidly. It is also the most expert
and active swimmer of any of our common leeches. When swimming
it turns edgewise and undulates the body in eel-like fashion, sometimes
elevating the head above the surface. |

Although somewhat of a scavenger, it subsists chiefly on aquatic
insects and their larve, and aquatic oligochaetes, but will attack fishes
and frogs or draw blood from the legs of wading boys. Not in-
frequently cannibalistic tendencies appear, large individuals devouring
the smaller ones of their own species. It is very active in seeking food
and will pursue its prey with considerable tenacity.

Breeding continues over a long period—most of the spring and
summer. Spermatophores are formed and attached to any part of the
body except the anterior end which seems to be avoided. In copula-
tion the two leeches wind about each other and adhere by means of
their suckers and the exchange of spermatophores may be mutual.
The small, flat, amber-colored egg cases are familiar objects to stu-
dents of fresh water life and are often found in great numbers attached
to the underside of stones etc. in the water.

Genus Nephelopsis Verrill.

Size large; much depressed posteriorly. Sperm duct forms a
loop as in Erfobdella; atrial cornua prominent and with a complete
spiral turn. All annuli of complete somites more or less distinctly
subdivided.

Nephelopsis obscura Verrill.
(Plate V. figs. 35, 36; Plate VI. fig. 40)

Nephelopsis obscura Verrill (1872).

Description—Like the species last described this is a rather large
leech, attaining a length nearly equal to Erpobdella punctata and con-
siderably exceeding it in the breadth of the posterior region of the
body. Compared with other species of the family belonging to the
Minnesota fauna the body is more depressed and in its posterior part
very much broader than they. The margins are sharp and prominent.
The region anterior to the clitellum is relatively slender and sub-
depressed with rounded margins. Texture hard and firm.

Nothing characteristic appears in connection with the mouth and
lip which is rather broad. There are four pairs of eyes of about equal

124 THE LEECHES OF MINNESOTA

size; the anterior two pairs are situated nearly side by side in somite
II, or the more lateral pair in a slightly more caudal position on the
furrow II/III. Both are directed forward and slightly lateral. The
remaining two pairs are situated farther back but similarly close to-
gether on the sides of the oral annulus IV. Usually they are on the
posterior part of the larger annulus but their pigment cups may lie be-
neath the furrow a2/a3. Both are directed caudad and laterad.

Fifteen annuli, X b5 to XIII a2 inclusive, are occupied by the
prominent clitellum. The external genital orifices are separated by
two annuli situated as in E. punctata at the furrows XII b2/a2 and
XII b5/b6 respectively. In individuals which are in active sexual
condition, the male orifice is a conspicuous opening more or less ele-
vated on pouted lips marked by radiating furrows. Occasionally the
genital bursa is everted as an elliptical disc with a central platform-
like elevation perforated by a single median pore or a pair of pores, de-
pendent on the more or less complete protrusion of the organ. In small
individuals and those not sexually active the male pore is minute, as
the female invariably is.

The anus is a rather large transverse slit with wrinkled margins
situated in XXVI and succeeded by several rather ill defined annuli
belonging to XX VII. The caudal sucker is a thin, flat, expansive and
largely exposed disc. Its dorsal surface is marked as in E. punctata
by six or eight radiating ridges. .

In one respect the reproductive organs are very characteristic.
While in general resembling E. punctata the atrial cornua are larger
and coiled in a complete spiral turn, which is invariably present in a
large number of individuals of all sizes and conditions which have
been dissected. The pre-atrial loops reach to ganglion XT.

The ground color is generally gray, clay color or brownish, the lat-
ter occurring most frequently on plain unspotted examples. By far the
greater number of specimens are thickly spotted over the entire dorsal
surface with black. These blotches are not coarse and heavy as in
Hemopis marmoratis to which the species exhibits some resemblance
in color, but are finely branched and ramifying, with frequently anas-
tomosed terminal branches, thus affecting a more or less evident and
continuous network. Sometimes the black spots are quite few and
remote, again they become so predominant that the ground color is
very largely obliterated and the dorsum presents a generally slate
black color spotted more or less remotely with the lighter ground.

In any case, whether the spots be few or many, there is no evident

THE LEECHES OF MINNESOTA 125

metamerism in its pattern and no tendency toward the formation of
longitudinal stripes, the pigment being quite as continuous across the
middle line as elsewhere. Except in the very heavily blotched speci-
mens, in which a few spots occur, especially toward the margins, the
ventral surface is immaculate.

Habits—The exact geographical range of this species is not yet
known but it is especially characteristic of the Mississippi Valley and
the lake region drained by the headwaters and tributaries of that river.
It is exceedingly abundant in Wyoming, Wisconsin and Minnesota,
but is known to extend as far south as Alabama. The stomachs con-
tain large numbers of insect larvee, which appear to furnish the chief
sustenance, but also various species of Oligocheta, aquatic snails etc.
No opportunity has been afforded me to study the habits of this species
but there is no reason to believe that they differ materially from those
of E. punctata. Verrill has described the egg cases as “broad oval or
elliptical, terminating in a point or mucro at each end, flat below,
smooth and slightly convex above, with a thin margin. They were 5.5
mm. to 8 mm. long by 3.5 mm. to 4 mm. broad.”

Genus Dina R. Blanchard.

Size rather small; not greatly depressed posteriorly. Sperm
duct not forming a long anterior loop reaching to ganglion XI; atrial
cornua small. Last annulus of each complete somite obviously en-
larged and subdivided.

Dina parva. sp. nov.
(Plate V. figs. 33, 34; Plate VI, figs. 41, 43.)

Description—A number of small and imperfectly preserved leech-
es from Gull Lake show characters which readily distinguish them
from any species of Dina previously described. The species exhibits
certain resemblances to Nephelis fervida Verrill, and may indeed prove
to be that species instead of the one which was so identified in my
paper on the leeches of Illinois. There is nothing in the original
description of N. fervida except the size which will permit one to
discriminate between the two.

None of the specimens at hand exeed an inch in length in the
partly contracted state and if alive and extended would not be more
than one and one-half inches., Posteriorly the body is relatively wide
and flat but anteriorly becomes nearly circular behind the mouth. The
mouth and lips have the customary form. Unlike most of our Amer-

126 THE LEECHES OF MINNESOTA

ican species there are four pairs of conspicuous black eyes, though
variations in which one or both of the anterior lateral ones are absent
occur in about ten per cent of those studied. The anterior eyes are
larger than the posterior, those of the two pairs almost in contact and
their pigment cups situated well within somite III. The posterior
eyes are smaller, looking outwards and backwards from the lateral
faces of the posterior part of IV.

The genital orifices are separated by a greater distance (normally
three and one-half annuli) than is the case in any other known Ameri-
can species. The male pore is a conspicuous transverse opening ele-
vated on a broad low papilla in the middle of XII a2, and the female
a very minute opening between the annuli XIII b7/b2. Considerable
variation, in the posterior direction, occurs in the position of the
male pore. In about five per cent of the cases it has been found at
the posterior part of its annulus, in the succeeding furrow (XII
a2/b5) or even within the annulus XII b5. No variations in the posi-
tion of the female opening have been observed. Nothing of im-
portance can be noted with regard to the nephridiopores, anus or
posterior sucker.

Concerning the annulation reference may be made to figures 33
and 34 on Plate V and figure 43 on Plate VI. Both somites II and
IIT appear to be biannulate and at least the outermost pair of eyes of
the anterior group are well within the latter. Somite V is also biannu-
late, VI triannulate and VII quadriannulate. Beginning with VII annu-
lus b6 shows its larger size and by IX is fully subdivided. In most of
the complete quinquiannulate somites, of which there are seventeen
(VIII to XXIV), this large size of b6 and its subdivision is very clear-
ly manifested. Toward the caudal end XXV is quadriannulate, XX VI
triannulate and X XVII two or three small rings behind the anus.

Owing to maceration the characters of the testes cannot be ‘satis-
factorily determined but apparently they are even smaller and more
numerous than usual in the family. The specialized anterior portion
of the vasa deferentia extends through a smaller number of somites
than usual, the sperm sac reaching from ganglion XVI only to XIV or
thereabout, within which region it is of large size and much folded.
The pre-atrial loop of the ejaculatory canal reaches to ganglion XI and
just before entering the atrial cornua the duct is folded laterally sev-
eral times. The atrium itself has simply curved horns. Its median

part crowds the twelfth ganglion somewhat caudad out of its usual
position.

THE LEECHES OF MINNESOTA 127

Whatever pigment may have been present has faded out com-
pletely in the preserved material. Nothing is known concerning the
habits of this species.

Dina fervida (Verrill) Moore.
(Plate VI, fig. 42)

Nephelis fervida Verrill (1874).
Dina fervida Moore (1901)

Description—The length of this species is not known to exceed
three inches and more often reaches but two. The body is depressed
posteriorly but rounded anteriorly. The mouth is of relatively large
size and the lips broadly rounded. More characteristic is the large
size of the caudal sucker which has a greater expanse than in most
small nephelids, the anterior margin being more widely free and reach-
ing as far forward as XXV a2. If one may judge from the prepara-
tions the body is not of particularly firm consistency ; certain it is that
the muscular system is less well developed than in the hard species.
The usual thick prominent clitellum reaches from X b5 to XIII a2
covering fifteen annuli. The external genital orifices are separated
by two annuli, the male being situated at XII b2/a2, the female at
XII b5/b6. Three pairs of eyes are more usual than four. They re-
semble those of E. punctata except that the pigment cups of the first
pair lie chiefly within somite III.

There is little of diagnostic value in the annulation. Some
features of the sense organs are peculiar but have no considerable
value in defining species. The‘last annulus (b6) of each somite is
much longer and more fully and constantly subdivided than any of
the others, as in other members of the genus.

The species is very readily distinguished from D. parva by the
character of the reproductive organs. The testes occupy the lateral
portions of somites XVIII to XXIV, and average in the one in-
dividual in which they were all counted thirty-two on each side of
a somite. The several regions of the sperm ducts exhibit no peculiari-
ties until the atrium is reached. Here the entire absence of a pre-
atrial loop is noted, the ejaculatory canals stopping abruptly at the
apices of the atrial cornua into which they enter. When the copu-
latory organ is fully retracted the ducti form no loop whatever anterior
to the atrium but when, in protrusion, the cornua are drawn somewhat
- caudad, they sweep somewhat anterior to it in a broad curve. The
atrium itself is characterized by the relatively large size and quite un-

THE LEECHES OF MINNESOTA

|
to
5

divided form of the median portion and the widely divergent short
cornua. In these respects and also in the fact that the prostate gland
covers the dorsum of the median chamber as well as the bases of the
cornua, this species resembles D. microstoma most closely.

Two distinct color varieties occur, both of which have a dusky
red color, during life, due to the blood. In one, pigment appears to be
nearly or quite absent, a condition which characterizes all of the
young and a few of the adults. The other and more usual variety
has the dorsum marked with more or less numerous minute black
flecks which vary greatly in number and somewhat in arrangement.
Many specimens are so little pigmented as to appear quite light col-
cred; such are usually marked with a pair of dark longitudinal stripes
one on each side of a clear median area, in others these stripes become
very broad and in still others the whole dorsum except the margins
is deeply pigmented.

Habits—So far as now known Dina fervida belongs to the fauna
of the Great Lakes and the immediately surrounding region, where it
is quite common. The food contents of the stomach consist largely
of tubificid worms and some insect larve. Verrill has described the
egg capsules which are attached to the leaves of Nuphar as “broad-
oval or elliptical, above smooth and convex, translucent yellowish
brown, with a thin, flat lighter border, each end prolonged into a short
tubular neck, with a terminal orifice. Lower surface flat.” They meas-
ure from 9.5 to 11.5 mm. long which seems remarkably large for a
species of the size of this.

PLATES I-VI
AND

EXPLANATIONS

Part III

GENERAL EXPLANATIONS

Roman numerals I to XXXIV refer to somites.
The letters a, b, c and d with Arabic numerals refer to the annulli.
For a full explanation see pages 17 to 19.

The cutaneous papillz are designated as follows:

dM name cast ajs nines 6 2 dorso-lateral
(G08 6 cept onary Ae dorso-marginal
19010) Dich aa AI aera dorso-median
1010) =e a a ee Pe median

STM Pee Mien tees Pees supra-marginal

The metameric sensillz are designated as follows :—

Ga hc a ai ee dorso-lateral

Aitilegerew ss Noten cider sr dorso-marginal

TINGE apap ss Betula Bhctanael 5 dorso-median

Sibitleparce sacs teed saci et sub-marginal

Silents ss sn 2 eSUpra-maremal

Ni iis telah ee Karen ventro-marginal

(VAUMS PERM ote ah egos c e ventro-median

Sree ee: Male, or the external opening of the male genital organs

or its position.
Ohi Cees Female, or the external opening of the female genital
organs or its position.

Special legends will be found in the explanations of the respective
plates.

Loe |
oa

Fig.

Fig.

Fig.

bo

N

PEATE AL

Glossiphonia stagnalis. x 20.

_ Dorsal view of the first twelve somites. The positions of the

genital pores on the ventral side are also indicated.
a a a nuchal gland.
Glossiphonia nepheloidea. x 56.

. Dorsal view of the first ten somites.

Glossiphonia fusca. x 30.

. Dorsal view of the first ten somites of a young example,

showing the metameric sensillz and papille.

Glossiphonia complanata. x 18.

. Dorsal view of the first ten somites. The paramedian stripes

are shown but the papille and sensillz are omitted.
Placobdella montifera. x 13.

. Outlines of part of the reproductive organs, dissected. The

folds of the epididymis and ejaculatory canal are drawn
aside to show their length. A portion of the ventral nerve
cord is included to show the segmental position of the parts.

Abs aoe ssi Atrium

Mem Wnt Ejaculatory canal of the spermduct
CDingreuis Epididymis

OVieco2at Ovary or ovarian sac

CD seoaeass First testis

5 | eer Vas deferens

Placobdella rugosa. x 5.

. Dorsal view of the first ten somites. All of the papillae and

most of the metameric sensilla are shown but not the color
pattern.

Placobdella parasitica. x 5.

. Dorsal view of the first twelve somites. The dark colored

background is shown by stippling, the yellow vitta and spot

being plain. The papille are omitted but the positions of

the genital orifices on the ventral side are indicated.
Papille and sensilla of the right half of the dorsal surface

of somite XIX of a medium-sized example. The lines to

the right indicate the relative positions of the furrows on the

ventral side.

Placobdella rugosa. x 5.

Papille and sensille of the dorsal surface of the right half
of somite XIX of a large example. The lines to the right

indicate the relative positions of the furrows on the ventral
side.

Plate I

mi wip tndp aa re : FY

Glossiphonia. Placobdella.

Fig.
Fig.

o
o
fo)
Fig.
Oo

10.

mp Oe

Loe
14.
15:

PEALE Tt.

Placobdella montifera. x 4.5.

The principal features of the external morphology of the
dorsum of somites I-XII. Very slightly diagrammatic.

Placobdella hollensis. x 8.
Dorsal view of the first ten somites.

Hemiclepsis occidentalis. x 50.

2. Dorsal view of the first ten somites of a young example still

remaining with the parent, showing the annuli and the
eyes.

Placobdella pediculata. x 3.5.

Ventral view of the anterior thirteen somites.
Dorsal view of the anterior thirteen somites.
The head end as seen from in front.

Figs. 16, 17 and 18. Dorsal, ventral and lateral view respectively of

the posterior end, showing the annulation and the peculiar-
ities of the caudal sucker and its peduncle.

Plate II

Cu
mp md dlp dl a
CS aa

Placobdella. Hemiclepsis.

PLATELET:

Actinobdella inequiannulata.

Fig. 19. The external morphology of the dorsal surface. Somites
XIJI-XXI are omitted as they are precisely similar to those
immediately preceding and following them. The furrows
are drawn more regularly than they are in nature. x 35.

Fig. 20. A small portion of the margin of the caudal sucker, viewed
from within, showing four of the papilla. The gland
ducts are stippled and the muscles are represented by lines.
x 130;

Piscicola punctata.

Fig. 21. The first twelve and one half somites seen from the left side,
showing the annulation as it appears in a well extended
example. The limits of the somites anterior to VII and of
X and XI are open to some doubt. x 35.

Fig. 22. The dissected reproductive organs seen from the dorsal side.
The testes of the right side and the ovary of the left side
are omitted. The left spermduct is drawn forward to dis-
play its parts more fully.

cles a oi: Ejaculatory canal of the spermduct.
(24 0 eee Prostate gland.

OME ae Ovary

SS 42 eerp Sperm sac.

Vide cas Vas deferens

Vet eee Vas efferens

tl-t5 ....Testes of the left side
Hemopis lateralis. x 5.

Fig. 23. Lateral view of the first eight somites, showing the annulation
and eyes of the left side.

Plate III

Piscicola. Haemopis.

Actinobdella.

bo
on

PEATE Ly:

Macrobdella decora. x 5.

. Dorsal view of the anterior nine somites showing the annula-

tion, sensilla and metameric color features. The lightly
stippled blotches are red and the heavily stippled ones are
black.

Dorsal view of the posterior four trunk somites and sucker.

Hemopis grandis.

. Dorsal view of the anterior eight somites. X 5.
. Ventral view of the anterior eight somites. X 5.
. Dorsal view of several posterior somites. X 3.

Hemopis plumbeus. x 3.3.

Dorsal view of the anterior eight somites, showing metameric
sensilla and black blotches.
Ventral view of the anterior eight somites.

. Dorsal view of several of the posterior somites.

Hemopis marmoratus. x 5.

Lateral view of the anterior end, showing the annulation and
metameric sensillz.

Plate IV

Macrobdella. Heemopis.

PLATE V-.

Dina parva. x 22.5.

Fig. 33. Dorsal view of the first nine somites, showing the annulation.
Fig. 34. Dorsal view of several posterior somites, showing the annula-
tion.

Nephelopsis obscura. x 5.

Fig. 35. Dorsal view of the first nine somites, showing the annulation.
Fig. 36. Ventral view of the first nine somites.

Hemopis grandis. x 3.

Fig. 37. Dorsal view of the characteristic portions of the reproductive
organs dissected out. The right sperm sac and the epi-
didymis have been somewhat displaced to better expose the

vagina &c.
die cmnec et Atrium
dees cre, Ejaculatory canal of the spermduct
Dae ese Albumen gland
a 0 i aa Prostate gland
(otal cbae Navarre Common oviduct
OV Sie aha Ovary
SS..hiac os... perm: sac
8 ly og Testes
Vast otek Vagina
Wi eR ei Vas deferns

Macrobdella decora. x 4.

Fig. 38. Dorsal view of the reproductive organs somewhat dissected

out.
Cole Sota iee Copulatory glands
Os AS oe: Oviduct
OSPR nee «Ege sac

Other letters as for figure 37.

Plate V

Hemopis. Macrobdella.

Dina. Nephelopsis.

Fig.

ro eon

see

43.

PRATE Vi.

At Ste. ited Atrium
(0 ea eae Ejaculatory canal of the spermduct
Olea ey Closed end of ovarian sac
OV. seeds Ovary or ovarian sac
Pave Right prostate horn of the atrium
Sica Sperm sac
tPaeaee Testis or testes sac
Valeo aes Vas deferens
ole ee en female genital orifice

Erpobdella punctata. x 7.5.

Dorsal view of the dissected reproductive organs. All the
testes, the spermduct on the right side and the ovary on
the left side have been omitted.

Nephelopsis obscura. x 5.

Dorsal view of the reproductive organs. Only about one
half of the testes of the left side of somite XVIII is shown.
The ovary of the left side and all of the testes and most of
the vas deferens of the right side have been omitted.

Dina parva. x 10.5.
Dorsal view of part of the reproductive organs.

Dina fervida. x 7.5.

. Dorsal view of the reproductive organs. The testes and

collecting portions of the vasa deferentia are not shown.
Dina parva. x 22.5.

The annulation of the anterior nine somites as seen from the
ventral side.

Plate VI

Dina.

Erpobdella. Nephelopsis.

INDEX

The figures in boldface refer to the pages on which the descriptions are
begun.
The Roman numerals in parentheses refer to the plates.

PMCGAMLENG) IDOL LAMM TRACT eRe ee atils, Son Shc, auh, Patel a MA ORNS eae erp Nae 99, 104
AcuinoapCellacinequiannulata. «0.5 chee. 5 es See ee eae 99; =(11TE)
[ial OTT Sa (Gy cae acer een ale eI a EAN Ratti Cosh Ta 102
ENT LASE OMT ACU Sti ee ad cba al sslenctes a cn Beye Reed ao oy cheno ee By et eee eae I10
ECU Se MAMMA ON oe) S catiat Shar id Ste oe fa cds: eye RA Ee Lt eee eae 48
EA Hatonmly Ol leeches Extermale ws koe: yamine otart oe Me one ecw ae 8
INRA COE) le RO earn i A ere Ser Se RR oe Nee to yy Wn Tol UP. ey REED 17
PNOEUEV TUL Epa as vais see Sis ia EUS ah sore Elna Dn ers ah eMM Ate or ev Ne ae hens ea cees 9
PMID IML CBO TIME ete ceo ad, acces oe niieeeacd Peck he OME NER Coe Nea al ek ee cto 9
JANA AY RIE CLA ie ears eo Ee Ge, AA SR Se od OM LOY Gee ROE RSS ec eke 9
AUCEUMID CHAO Ie y Meech teas at slate See he ane iter Ue ae ce 10
GESTIOMAMONM OLE eturea sates SE za ats he OBS, aS ane 12
JAVANBIS 18-2, CGP ee eae OO Re a eR SL PME eM a ts Aur Sacra cob 18
Hell OOM IES SEIS! = SOME a ear Malas, sie gs eae ave noe eee ee 18
Nem Sp ON OR eins tt NE ee afi Shes ts el hiachea eae sy oA rear cr ees eee eee 19
eater Sarena che 22) este i/o los ici fae ack, Saye hers head Bes oa 19
Ceca OasthiC atid: (MteStitials.. Wee sek, 23/4 Suadt Sane eae eae 18
(Orca tome SVSECIM: ye acy a ..0xS 2 doer ee manne Gls eran eee 18
(CHET OS TANG ay i a ra rE MSSM 8 A oj dye 39
(CADTPGTEI EG) Aa eies a Ra mE RON eer Ie NEED ec 88, 99
CIITA CIS eas. ee a ROR ROU Cen RRO OME weet! oS, ak, 82
Moy rts nae eee hehe cate ese SER PA ecogls ea ne A saat ak a 43, 47, 94
IUGR aN path sere lg ote a ito ete dis tereas ese uel Vee ee en a7
MEI MCU Cay aay iste ojetha 4/4 <item thy a n- ahas gae ey oa ee 76
OCC Meme Sas tac chee ies Asia, ht aN ee 96, 98
OmllataacViadiren GCOS: «cma; oak ie eas. Seige Se ee ee ee 86
Papiliteran var, Caritiata),..c v)J0 so ode 5 owe are eee 88
papulltitecaccvaty limeatay <0. bie t.cn aa eens 2 oy ee eee 80
PAAR Ce serio cia wtoere eS ache nan fe: anc wip RAs eee eae 48, 50
CHG Dy a eat dR Te Te SIME VG ME oh 18
MeschipmonsoL, Wiinmesota. Jeeches ; =a. cseumoee oe were 75-128
Weveclopmient Ormteeches, 4... «ches oy ate seeds eee eeatan open ae 21
TB NCIS aig ENC RRS aS ee ee a Perch et Eee a pens ee 17
DONT ete oie Bc a or Oe BREA Ath on, Bx Me ce a 125

146 THE LEECHES OF MINNESOTA
fervida, Habits Of Six +. eee ae ce ese eee 128
MLICTOSEOMIA > Pa iam cf. % 41G caene ee near ot Oe ae ee ree ene 128
DAVE. Foad-cis 3 gage ayn & epee eae 125, (V2 VL) eie7,
Habits iOP 7 livin. G2 che ate oe Dee one eee ee 127
Economic. importance ob leechies: 5 a, crn sn. ee 5
Effects. of bloodstuclsine. by leeches... 5 cee eek a eee 5
EUG r Oe VA YAMPA SiR eae aot a pea escalate Oe 21
Brpobdelilas +: 7.\:\e teak oY os gees ete ey ore ee eee cia Gem L231, 128
puUNnctata!: kya. en eee reer EES; 227, (1V"), 12a see ee
Habits: Ofa acu Sole ihe! peed cad ern eave She eee [22
EUS OPA SUIS het Fo wget by Oates GNM reas BSR Sea Sacer co eee 7,
Mxeretory ‘System ort leeches. te sym see eas eee 19
Ppernal characters; op leecehies., gic sie etc ee serene 8
Hives: Of leeches jaw at suc Ae tosiany cacy Pallas pie meee 14
DRATSYIX Wai Ae .2 eae neue a) wives rome Oa eRe oe Kt meee ee L7
emRUL ZATION 230 dein wate soe Oe le tn 2) teres ne en ae 20
Glands, :esofaceall 4: 4.0.8 oo lets. cook oeieek es oe. C 2 eee eee 1)
SI lG gp Gamera Se UaN PL eA NORE PEO: 5, SNORT ahha oo ae < 107!
SiC Leer 055 ates otek weetikia ai ge ne yee ties ens oo! ee sen 50
Giessiphi@iiia) ses atveees eo aeons aati melee ue eee 13, 43, 75» 96
COmplanata She tek o leis cs cs <- ce eee 77. Os 1O2s Melby
habits Of hae ax iho clea es ee es ee ee eee 83
Clomeata ,, S2.ce hed e ones Sue haee enti een: Sa alae eee 76
BUSES: Riad oe Med ie a Acie eee ee ieee teen 80; ()e-82
habits! @f plcs..bec alee ees, ites cece ee ee 81
lineata. <<. .|s\2.2ce Se eee eae Le eee © ere hee eee eee 80
nepheloideawes swe orer- seis ee fino a Ph oe SNe Nye roe eee 70; aly)
habits. OF 22 Ses. = 2 ae Ook Fae ee eee eee 77
DaAFASILICA. 4) alchatee eo castes dean lee Oates tr ieune treeeeae 84
Shao ta lis: Okie gas ee tas ee ee 655517700 Cl hoo abe2
habitec@is ce aye stvis ye. eee ce peace Os be ee eae 79
triserialiss 22... 2s te 5 hee See aan el eee 81
(Glessiplonidzes. ae01025.7 aaa ate aes Aker Q, 43, 75,/02, 97-102, 120
Greachobdellidze:. sscteick aaah es oe ore ae oe ee ee 17
Egemadipsa ceylonica;babite (Of, yaRstaaa te eee eee 6
Iizeiiveniterial: i... ct. sl. aroma Gets eminence ee 43
Remocrecarina stelanovi 16... ee teoepar eo A ee ee 50
FZSHN@ PIS: \s ..t:0aP ade ten, Sek eye ee Oe 2, JO. 100, 120

SAT ATNCULS)s 5 sk" hes ey ether ck ees oe Meee 20, CA); 1rSs, 16, 117 aa Vee)

THE LEECHES: OF MINNESOTA

ate aea biel NESE Queen cI pO eM CEE eet (4 «hes tems tate Mian he Sato
Heise Tact Shea rere icici sesties Coy eee eee ne Mie eerts, ACULT). RPS nig

HUMOR ACIS serena nya Shs Gils SEES ake eee Ae BIO; w(( EW) eho = LEO!
Bas MO dita, cea oN wad CPR, STAY Manlio reet eels
PRGA DE US. Sera enee ice her weet gese oxi ee 1P55. (00 V2) 21ne:
IAMS p pO ces mask SA nb a. others eee fue fie, RA
Melo MD Wells StASMAliS. Siu halt nicn 2 2 Card cos eocs eye, estes ee
HalRINIGIE Danser ma inp aur colt Met are ence sil Wart via hchueernay (ae 43, 90, 96,
(CRIP dM A ee OR alae Ae IM MEO) Ge

Irae OX) GK SI AN Pe Genres We eR ee REN Cs Te tae Raa nee ot 58)
[a iugulelihahiGear 5 ec eae ea eee eee a ee nie Ha LS 105,
Hirudo*
Bic Ulerta tems ace ia A ot a. < Si i cds Ac eeees oh ope ee
COMI MAMM At ches iota ees eects PS: x cite, Arsh snartn chal hace cheeks Sonn oe ae
GES OIE, Ay Rat ae ce ee Re OE RE CAME DY 2a URE HEA
Wei etec SOM feet ie Pee ae, 84.00 urese senses Whayh waem sths oie ahe, muate rcases Lie)
italics tafe MAINE Ses a2 SE Lo Rh eh a gee NN 80,
AMPS TAN OV RN EE Par uA ghee) AEE rane acne CNG asec uaa ean Ric. che oe ae
TURN CHINA WU Sy MER epee s, Mian: se citi naelgrs aia ones soars aeeeaee 7138s
[Ei PEUSHN CYA rey oy acca ee AER ge RR RRR CT Peta RINE PE Fo
S(ATVOVOICULICL OI Cake Seen ents gece ea eee ee ne, Oe See
HEN Cass om cee CTE Per agate at 5 PERS che ANS ry ele Bea e AG) | ines wae ee
Nemtinvobdellacmunctatan .sa 5 -Acnt soe foe nie See ee ena eee
ike lnitstaay@ mele liiclaat sn Nerereas wah aus nei ath Yorenes Sadlforos tales) myles seereneen eee 98, 99,
iste SUMMER ere eRe the cag Wahu, or goats Sear c ce Ree a esau ae iene Rewer
[DANES ceric So Reka 8 GRO ERO Oe ee ee nee ae ee eee
BES atom iitlesotamlecChes:, can. .vuk tilt monn eae ape hein
Beeches = ceneraly antroduction. «4-4. -1 larga hoe Grier
PAG Gatien ec Chia ly wait." ays eo tee nena aeeaut: Ot Ue wach 6,
Detect TUOR Ge tee kee N cs ee eh te ee hee ee ee 4,
(Reomommie-tipPOr tame Ole». 2, a eeus aes ote a once eee
Eonar CharaCters.Ol. cy... oc 9 reap eee wees ve ke eek
EAI MISUR@ Derek rcta:/< Ro kx nw ye CMe aan ere erst ee ROD: ee et
iret atrAGOATEY: OL 4 sce8 ie Weel Varah ors cok wha ede Re ek age bas
evecoy Mianinescta- species. Of: 64 .)%.'<ascls ash, ¥ we mam wrt

—
(Spe)
o1 OV

CO uN

ioe)

148 THE LEECHES OF MINNESOTA
Nervots: SyStem Of y.>. 31. %-n0¥e 5 ses eee Dee 19, 36
Numberrot ispecies sot «<0 sft’ caer cule oe 4
Reproductiv system of s.1. eh ae eo en cee one eee ene 20
Sense Organs ORF 2s ies Gia ol eet e pasion ate nora aa 14
Warieties lot medicinal 2 'n%.ssniae ae ter are eee 6, 7
Dearne ts Sass ARM et op a ad ich ae ee Ged cle ei eee res
WacrObdellat 2 ;\.4) so tiunh s genie aoe oemcts meer cuss 13; 70; 200, 110.) 7a
EEO Wes alate, GA) co rvigds Caen MA ee etn eee 6, 135 106; (LV,
Haat) (OL Are gras Sere Set ener he 2 Penal Pe 10g
SUOAGE 5 ook: hom Mate ae a ree er eae ee Ab 8 a 5B ge 13 7)
MAMI V ide ae. Scouse aeen ance one tee ania yee ee ee 9 es Be Pe 1 /
Medicinal leech! .a-35 .Aaacnets re nate Si tate aoe a ee de err eee 6
PATOL ICAL hits. cE tals Be a, tec geen echt oa oe 106
Eiropean WaArMeties) Of oa), cayacm isan © shi aca cee 7
PLA DATS S08, cole gids e cic kt ale Tie tee Des Lie OE be | 7,
WEG PAIMIER Ee c5.\iiticlve dglee oiaie cote be See ARS cose eee eee fe)
We GATE RISIM, . jc ics nls os fe-8 one Sue eee he. 22, sas ee nee ee if)
BMW eta Li 2 cee ts tetas, se, Ses eave eta Re a RET NED St os (oer a 17
INGEridiOpOre: 4 ii detec. eo he eee ae 3 se eee are 19
Ie Hasidic ects, Svs coe as gichecte send ay act gre ah eet ete Oe ac (0 ee eee 19, 50
INiephiclis( sto. Ame ao teeth ees oe eenein= oss aay gee 25. 4G
FEPNACANR .°. ull rl ate ah archaea ete oe eee 125, 127
Teste nalis 2 hi Phe ag dele easlen cele ete oneal ee ele Oe a 21
PUNChAtAs svi. calgalase occa. ain is sto aemomeneas leaning ep eaeh ae 12]
ING PHELODSIS a.m draw cane ca eaie sine eye eet clever oie Re tan ene 123
OPS GUSTS 2 ay ctecieel as ecsescsh hey GPE crepe, nen ot mene oer £23;/ (We, VAD)
Habits Ob <1. euens te sone to) ete ee eee 125
INEPMGICIOPOLE <.40x 24.) cise ats ois eieys ya een ee eee 19
IEP MT CTUM., Ae eben Bey. - ws hoot ose coe Oe mane toner dee een 19, 50
Merve Of; Falvressag ota.ne eaten eee ea a 38, 42
StOMMatOSaStricy ahi Ageia sok cba oes eee ee Ac. 3)
Nervous system of leeches: 241-24. ase ee ee 19, 36
Rlacobdella: pedictlata 2 i. aca. 1d are ee oe ae)
INGREOSEONIUMG pf vrgcencraz eth sce -g he eke dcr IS caps See tore IOI
Oesophacus. nif ul4eee ew de Som ates a ete See esofagus
@VAMleS.) 83s). seas sad OS, eos AR Ae ene Soe oe eer nen eee 20
Ozobranchus® 05 24,2 ewes) Baca See SEA ae teers ee 19
WPERIS. oie co hledh oe cane eon 0 eA > Sec cnc ee 20

PAPA Ry MReiges 2 ait, Gone ae: doh ae ee Ree eee ae See farynx

THE LEECHES OF MINNESOTA 149

ES RG ie) lees 0 ee ice sence poor oe aca 13, 99, 103
Bie OUNCE Marto) she lsncne rate oa > ey SiaeaueheNe, acy Tae SS 103
ISGAVOEW Eh ity Rb Sitar Parr OGD aay hai Ueki aC cy ads FO3% HLT)

TRAM SA SORE Neaiie sn catth’ or oc peer aish heen ebapanota ep nore apelin a van aReat eo lose 105

Fee TAT oes eee jo tten tai Sra (Suede ee te hateesn nina travel lene) © 79
FM ereant cle Uilicaee rere ree os clei, 2H 5 sivas sot erie So) she fe, SUlGviede ees 43, 82, 84, 90
CANUSINIIC Na ilo ¢ Nod pee ih ent tee IGOR 50

Fre lil sisu reser eres Siovece so koe ois lanes one era titrate Uanaamene 65, 94, (II)
Fara ty Re CM a ara etal Sli cca Bl Selah Maar Betta ener eete eatin oh 96

ATUGK CHC T AE Roe Le Slate a eave ley aiin ol eh deaecencenete 88; (1, 1D)

Oia Snes Ok iS rc OO Sa ae IRE Mrs WC ice 89
Parasiticaly cs... 21 (A), 35, 42, 50, 84, (1), 86, 87, 90-92, 94
TEST bi Epc LOH te jae I PP eh URC OVS No ontun i <c3C 85
DEGICMlatane si ty ae yo ee nen 35.(C; D, E), 90, A)

PNT AUGIUYpsOReE Ha. oe w oan tc a Sleayncrtys'® Si chee tae ATA tae 29
Anterior ganglionic mass of......... oy CNRS ee: Aa (EE)
WescriptiomrObin oa 2a... ote ae ed es ere eee 35 «€)

RV ESH OR ey Beets ha oy 28 ie Ane oh eersteneke wenden ek en 47

GHomndS Olam iie, ot os 4 ogitvs aid quent eons ce Ope neater ee 49

LEMMAS OR Mess eters. took clare os aan chante Sitamuenve ears Meckenie cusmeh mle 33

IIs Eontaygn OlEdee rap Meee n!snogSo0'0508 cpalisl ays ore) spat ah Vecae Ue vetetatcr 31
Miethodsmotmkilling: G2¢ 2 jc % aac. setae or eee eaten 31
INfepiniriGhias Qt say5 coi tcehelsk Sigtatale sleet, Yaeee ecmanae 50 (C)
Gentralenervous SyStemel s 25.5 orci oe ieaeerey 40 (E)
Rostenor canclionic mass: Of. 0.0 2 os. ae ene 46 (E)
ReMroductiy OLSallS-Ol usc. <tc sat eee rly a Gan DD)

GIO Sane Mt ates Ce Ft a a) wean eee lee 21 (A); 35, 86) (), 90

In Dhic (01) Rees eT eR eta Siciau 5 Sidr Cd 87
PRONOSTIC: CAM R Ue AnREA 1) Here RE Rr mmeeMe etary Dio, fon itis 17
(EROLOE LEP SiMe ate: heels bot staid ee oe ORD tee een eee 96
eOLO CLE MGISW Me crores ices Actas ces: Sims s lakes © ph epee ee NA et har teehee 96
BESSON aicretnce iret ars stro hood: Seca Na Sok Met ORR oe oreo ts Rates 43
ISCHIA Sa a aR eee em eR at PI re eck eatecus orcas < OiLie 18
Relationship of leeches....:......- 1055. . eset ees ewww ee ees: 21
Repecductiv System! . 0%. .-. 6s =. ois UN ena ee sei wie iene 20
Respiratory SYStEMI .. 0+). eens ea ste bin ih ae eet nnd: 19
Fy TOS MTS ay caine ears =. fomcas? 5 Om ie Manic NS eS ee saa) 17
See EMPAMIOMM Y's bccn sie 4 Cnsenye Qaiee b ak i MG eee a emer S? fe)

150 . THE LEECHES OF MINNESOTA

Semiscolex
SAMUS. iAerasdte-oi els «aire Rr ae ee ee inet E17)
. HEEMESELIS uc ceatie tates» 2 eo eae ieee eee, a dee eee
SOMmse “ORO TS s secure cosh-s dhsctbese-s me Pate ee ee eee Saie ee
SOMItens shen NES ON SEMEN te MTP er er
PETITES WOE ose ostend ctctrayete ioc ae ae ce ee eter Ba eee ee no EOS
SPeMMNARLCS\ 2.4 2 oncar te ae ae Saree ee RT PF
SMErMATOLOre: 4... stains eed ee ee Fe pee Sige a ee
SHOUMACI Mites terpatese ees OMe are 2a cook. ng hak Me
Stomatogastric Merve. aa 2 tt ceeert ok tues Cera eee
Sub-esofageal ganglion ............ Sse) eater, ace in er
Supra-esofageal ganglion) «<4 0 ss5% . «12 onl = cee ay
Sympathetic nervous system ................ Shs as 38, 39,
WPESEES 5 5¢.25.4 wh some ope Soca qunpore sy ue DuMont ists. G0) reine ae ee
EAS OE LETOMIS 3 ects c-fhsumre oie, sous Casey a ee ices: cine cae ea ce ah
Wentral nervescord’.2 23 se. eat eee ers 52: cc eee eee

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QL Geological and Natural History
1 Survey of Minnesota.

M575 Zoological series
V.5

Biological
& Medical

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