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State of Connecticut
State Geological and Natural History Survey
BULLETIN No. 26

THE
ARTHROSTRACA OF CONNECTICUT

2y
Fish
By Op 0 |g
B. W. KUNKEL Tse
Professor of Biology, Lafayette College 2b,

HARTFORD
PUBLISHED BY THE STATE
1918

BULLETINS

OF THE
State Geological and Natural History Survey
of Connecticut.

1. First Biennial Report of the Commissioners of the State
Geological and Natural History Survey, 1903-1904.

2. A Preliminary Report on the Protozoa of the Fresh
Waters of Connecticut: by Herbert William Conn. (Out of
print. To be obtained only in Vol. 1, including Bulletins 1-5.)

3. A Preliminary Report on the Hymeniales of Connecticut :
by Edward Albert White.

4. The Clays and Clay Industries of Connecticut: by Gerald
1 neis Loughlin.

5. The Ustilaginee, or Smuts, of Connecticut: by George
Verxins Clinton.

6. Manual of the Geology of Connecticut: by William North
Rice and Herbert Ernest Gregory. (Out of print, except in
bound volume. )

7. Preliminary Geological Map of Connecticut: by Herbert
Ernest Gregory and Henry Hollister Robinson.

8. Bibliography of Connecticut Geology: by Herbert Ernest
Gregory.

g. Second Biennial Report of the Commissioners of the
State Geological and Natural History Survey, 1905-1906.

Io. A Preliminary Report on the Algz of the Fresh Waters
of Connecticut: by Herbert William Conn and Lucia Washburn
(Hazen) Webster.

11. The Bryophytes of Connecticut: by Alexander William
Evans and George Elwood Nichols.

12. Third Biennial Report of the Commissioners of the State
Geological and Natural History Survey, 1907-1908.

13. The Lithology of Connecticut: by Joseph Barrell and
Gerald Francis Loughlin. ;

CATALOGUE SLIPS.

Connecticut. ‘State geological and natural history survey.

Bulletin no. 26. The Arthrostraca of Connecticut.
By B. W. Kunkel. Hartford, 1918.

750) i 0) OMI as 021: 3 Sco

Bibliography, p. 258-261.

Kunkel, Beverly Waugh, 1881 —

The Arthrostraca of Connecticut. By B. W.
Kunkel. Hartford, 1918.

261 pp., 84 figs., 25¢™.

Bibliography, p. 258-261.

CATALOGUE SLIPS.

Zoology.
Kunkel, B. W. The Arthrostraca of Connecticut.
Hartford, 1918.

261 pp., 84 figs., 25°™.
(Bulletin no. 26, Connecticut geological and natural history survey.)

Bibliography, p. 258-261.

Crustacea.

Kunkel, B. W. The Arthrostraca of Connecticut.
Hartford, 1918.

261 pp.,; 84 figs., 95cm,
(Bulletin no. 26, Connecticut geological and natural history survey. )

Bibliography, p. 258-261.

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Dtate of Gonnecticut
PUBLIC DOCUMENT No. 47

State Geological and Natural
History Survey

HERBERT E. GREGORY, SUPERINTENDENT

BULLETIN No. 26

HARTFORD
Printed by the State Geological and Natural History Survey
1918

State Geological and Natural History Survey

COMMISSIONERS
Marcus H. Hotcoms, Governor of Connecticut
ARTHUR TWINING HADLEY, President of Yale University
WILLIAM ARNOLD SHANKLIN, President of Wesleyan University
FLAVEL SWEETEN LUTHER, President of Trinity College
CHARLES LEwis BEACH, President of Connecticut Agricultural College
FREDERICK HENRY SYKES, President of Connecticut College for Women

SUPERINTENDENT

HERBERT E. GREGORY

Publication Approved by the Board of Contro

THE

ARTHROSTRACA OF CONNECTICUT

By
B. W. KUNKEL
Professor of Biology, Lafayette College

HARTFORD

Printed for the State Geological and Natural History Survey
1918

CONTENTS

PAGE

INTRODUCTION. : : : ¢ : : 9
Economic iperiance F - 4 ‘ : ; 11:
Classification of the Arthrostraca . : ; é é 13
PART 1. AMPHIPODA . : ; : : 15
Key to the Sub-orders of Amphipoda ; é f : 15
Anatomy ; : 5 ; 15
General Porn of ‘Bady and pele : c 3 i 15
Appendages : : : : LAM, : ! 18
Antenne : F : ; F : : 18

Mouth Parts ; : : 2 : 20
Gnathopods and BeReionods ? F : ; 23
Abdominal pe : ; ; 4 : 25

Sense Organs. : , 3 é : 26
Internal Anatomy : : 3 ; F E Ze
Sexual Differences. ; ‘ : : 4 3 31
Size ary ‘ ; : ; : : 5 ; 32
Color . : : ; : : : : : 32
Habitat : ; ; ; : é : 5 33
Movements. ; : , ; ; : E 35
Food . : E : 5 - t ; : 37
Enemies ; : : , , : ; 38
‘Resistance to Makerse Conditions ; ‘ ; : sess
Molting 5 : : ; 3 : : 39
Nests and Nest- Epaitding ; ; : ; c 3 39
Breeding Habits ; : : ‘ j ; : 40
List of Species : 3 : : : ; : 43
Hyperiidea : uM : : : ‘ ; 44
Gammaridea . : d : : F 47
Key to the genera of G@amandes : : : P 47
Caprellidea. : : : : 3 ‘ sue As
PART 2. Isopopa ; : : : F oa) 185
Key to the Sub-orders of Teqpeda : . ; 4 Ay ipltsis
External Anatomy . : ‘ : ‘ : all eS
Internal Anatomy : é é : : 5 ARS)
Biology : : ‘ : ; : : ap USS)

CONNELTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

PAGE
List of Species . E : : : ; » 3399
Key to the Genera of feapade : : : : 1 wee
Tanaioidea or Chelifera F : 5 2 : Sent ol Lees
Cymothoidea or Flabellifera ‘ : : : 7 BISR
Idotheoidea or Valvifera : 5 ; 3 : te Ze
Aselloidea or Asellota : : : : : eZzo0)
Bopyroidea or So eoiee ‘ ; ; : : “7235
Oniscoidea : F F ; c : 7 Zon
List OF FIGURES. : : 3 : . 2 RZD

RIBLIOGRALHY —. ; : : : : 1 ZS

INTRODUCTION.

The purpose of this report is three-fold; first, to describe
and figure as far as possible all the Arthrostraca which have
been collected within the limits of the State of Connecticut;
second, to describe briefly those forms which have been reported
from neighboring States only, but whose habitat probably ex-
tends to this region; and third, to furnish to the general student
an account of the anatomy and biology of the group as repre-
sented by species of this State. The Amphipoda will be treated
more fully than the Isopoda because the latter group has already.
been discussed, in the excellent account of the Rev. T. R. R.
Stebbing in his History of Crustacea (D. Appleton & Co., 1893)
PP. 314-435; in the briefer paper by Miss Richardson in the Pro-
ceedings of the United States National Museum, vol. 27, pp. 1-31,
1905; and in Harger’s valuable paper on the Marine Isopoda of
New England in the Report of the United States Commissioner
of Fisheries for 1878, pp. 297-462.

Among the works that have been consulted and have proven
of greatest value in the preparation of this report, may be men-
tioned Della Valle’s monograph on the Gammarini (Fauna und
Flora des Golfes von Neapel, vol. 20, pp. 1-296, 1893) and
Mayer’s work on the Caprellidea (Ibid., vol. 6, pp. 84-184, 1882,
and vol. 17, pp. 94-144, 1890.) These volumes contain very full
accounts of the anatomy and biology of the groups as a whole.
For the description of species, attention should be called to
Stebbing’s Gammaridea (Das Tierreich, Lief. 21, pp. 1-806,
1906), which gives descriptions and determinative keys with
full synonomy for all the Gammaridea described up to 1808,
and to G. O. Sars’s Crustacea of Norway (vol. 1, pp. 1-711,
1890-1894), in which the descriptions are particularly accurate
and the figures reliable. Without the help afforded by these
figures the labor of preparing the ones for this report would have
been vastly increased. The various publications of Holmes on
the North American Amphipoda have also been freely re-

Y)

Ke) CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

sorted to as the numerous references will testify. The works of
Miss Richardson, especially her monograph on the North Ameri-
can Isopoda (Bull. U. S. Nat. Mus., No. 54, 1905), of Oscar
Harger, and of G. O. Sars, have been very useful in the study of
Isopoda. Besides these, the classic Vineyard Sound report by
Verrill, Smith, and Harger (Rep. U. S. Com. Fish. for 1871-2,
pp. 295-747, 1874) and a Biological Survey of the Waters of
Woods Hole and Vicinity, by Sumner, Osburn, and Cole, (Bull.
Bur. of Fish., vol. 31, 1913) have proven mines of information
pertaining to the habits and natural history of the Arthrostraca
of Connecticut.

_ The material upon which this report is based consists largely
of the collections of Amphipoda and Isopoda made by the
United States Fish Commission at Noank, Connecticut, in the
summer of 1874, and very kindly loaned by the Smithsonian
Institution, and the extensive collections in Peabody Museum
of Yale University, made mostly by Professors Verrill and
Smith in the neighborhood of New Haven.

As might be expected, there are very few species from this
State which have not already been reported. Holmes in his
paper on the Amphipoda of Southern New England (Bull. U.
S. Bur. Fish., vol. 24, pp. 457-529, 1905) and in his key
to the Amphipoda of North America published in the
American Naturalist, (vol. 37, pp. 267-292) has reported all
the Amphipoda which have been found in Connecticut with
the exception of Photis reinhardi Kroyer, and one species
Tmetonyx quadratus which is here described and figured for the
first time. Miss Richardson has included in her key to the Isop-
oda of North America (Amer. Nat., vol. 34, pp. 207-230 and
295-309) all the species of Isopoda which we have met with in
the present study.

Notwithstanding the fact that so few additions to the fauna
of New England are made in this report, it is hoped that the
publication of the figures of native forms, together with a gen-
eral account of the anatomy and biology of the Arthrostraca,
will stimulate interest in this group and be of service to students.

No. 26.] ARTHROSTRACA OF CONNECTICUT. II

ECONOMIC IMPORTANCE.

Except for a few species which destroy submerged timbers,
the economic importance of the Arthrostraca is indefinite but
probably great on account of their large numbers and their
widely extended habitat. Many species perform an important
service as scavengers by destroying decaying matter along the
shore. According to Miss Richardson, certain parts of the
coast of France, where shark-fishing is carried on extensively,
would be almost uninhabitable were it not for the swarms of
Isopoda which consume the heads of the sharks which are
thrown back on the beach and which would otherwise become
highly offensive. Naturalists in the Arctic regions, where the
Amphipoda are especially numerous, obtain thoroughly cleaned
skeletons of bears and other animals by exposing their bodies
alongside of their boats to the shoals of small Amphipoda,
which pick them absolutely clean. According to Mr. Geoffrey
Smith in the Cambridge Natural History, Amphipoda, “when
crowded sufficiently, will even attack living fishes, and by
sheer press of numbers impede their escape and devour them
alive.” It is hardly possible, however, that any appreciable
number of fish are so destroyed.

The Amphipod, Chelura terebrans, and the Isopod, Limno-
ria lignorum, often occurring together as well as with the “ ship-
worm,” Teredo, do great damage by destroying submerged tim-
bers. Chelura is quite abundant on the European coast and has
been reported from Bermuda, but on the Atlantic coast of New
England it has been reported only from Woods Hole and Prov-
incetown, Massachusetts. At the latter place, Professor Verrill
found it from 8 to 12 feet below low water. (Smith, Proc. U. S.
Nat. Mus., vol 2, p. 232, 1879.)

Along the Connecticut shores Limnoria is the most important
crustacean which destroys timbers. Verrill, in the Report on
the Invertebrates of Vineyard Sound (p. 379), describes it as
eating burrows into solid wood to the depth of about half an
inch. These burrows may be so numerous that the outer layers
of the timbers decay rapidly and are washed away readily by
the waves, leaving a new surface which in turn is attacked by
the crustacean. It works chiefly in the softer parts of the wood
between the hard annual layers and avoids knots and those

12 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

parts which are impregnated by iron rust from spikes, etc. When
abundant it will destroy soft timber at the rate of half an inch
a year, thus reducing the diameter of a pile, for example, by
one inch in that time. On the average, however, the rate of de-
struction is only about half of this. As early as 1875 Andrews
observed Limnoria attacking the gutta percha of submarine tele-
graph cables. (Quart. Jour. Micro. Sci., ser. 2, vol. 15, p. 332,
1875.)

The holes made by this Isopod are nearly round and may be a
sixteenth of an inch in diameter. They go into the wood at all
angles and are usually more or less crooked. The species is con-
fined to a rather narrow zone extending a short distance above
and below low-water mark. The burrows are made by means of
the stout mandibles and the excavated material is eaten; thus
the burrow affords the animal both food and shelter.

The remedies against this animal are chiefly copper, or other
metallic sheathing, broad-headed iron nails driven close together,
and coal tar, creosote, or copper paint applied to those parts
which are liable to be attacked.

Certain of the terrestrial Isopoda also damage vegetation
to some extent by feeding upon the more tender portions of
plants. In Louisiana and Texas Armadillidium vulgare, accord-
ing to Miss Richardson, is a menace to cucumbers and other
plants grown in hot houses as well as to young cotton, and in
Virginia it is ““one of the most destructive pests with which
the mushroom grower has to deal.”

Besides the roles already mentioned, the Arthrostraca
are important as food for certain fishes, forming, with the
shrimps, a very large part of the food of most of our more
valuable edible fishes. Professor Verrill states that the Amphip-
oda occur in such immense numbers that they can nearly always
be obtained by the fishes that eat them, and that the voracious
blue fish feed upon them even when menhaden and other fishes
which they prey upon are plentiful in the same neighborhood.
Among the species of Amphipoda taken from the stomachs of
porgies, tom cod, and herring caught at Woods Hole and New
Haven, large numbers of Unciola irrorata, Ampelisca sp?,
Gammarus annulatus, G. locusta, Calliopius leviusculus, and
Leptocheirus pinguis have been recorded by Verrill.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 13

CLASSIFICATION OF THE ARTHROSTRACA.

The Amphipoda and Isopoda together constitute the tribe or ~
legion of the Malacostracous Crustacea known as the Arthros-
traca. The Arthrostraca are characterized by the absence of a
carapace, the head being fused with never more than one thoracic
segment, the presence of only seven free thoracic segments, a
single pair of maxillipeds, sessile eyes, and thoracic limbs which
are uniramous throughout life. The two groups in question
are sometimes referred to as the sessile-eyed Crustacea (Edrioph-
thalma) to distinguish them from the other Malacostraca in
which the eyes are mounted on movable stalks, the stalk-eyed
Crustacea (Podophthalma).

The Amphipoda may be defined as Arthrostraca in which the
body is generally strongly compressed from side to side; and with
the abdomen consisting typically of six segments and a telson. The
gills are borne on the inner side of the proximal joints of the
thoracic legs, and, corresponding to the position of the gills, the
heart lies in the anterior part of the body.

The Isopoda may be defined as Arthrostraca in which the body
is generally strongly flattened dorso-ventrally ; with the abdomen
composed of six segments, which may be partly or wholly fused
together, and the terminal one which is referred to as the
telson and is large and shield-like but rarely free; the respiratory
organs are borne on abdominal segments and consequently the
heart has an abdominal position.

The most important characteristics which distinguish the two
groups are: (1) The general form of the body which is flattened
in the Isopoda, and compressed laterally in the Amphipoda; and
(2) the respiratory organs, which are usually modified pleopods
in the Isopoda, and always appendages of the thoracic limbs in
the Amphipoda. In the former group the five anterior abdominal
appendages are usually broad plates which are all more or less
similar in shape and size. In the Amphipoda the first three
pairs are similar, being long, narrow appendages adapted for
swimming while the last three pairs are short and stiff and are
adapted for leaping.

The classification of the Amphipoda into families is not in
an entirely satisfactory condition. The group is very diversified
and there is a great difference of opinion regarding its proper

14 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.
subdivision. Della Valle groups all the Gammaridea into only
ten families. Sars recognizes twenty-five families in the Nor-
wegian fauna alone; Stebbing in the “ Challenger” Report
divided the Gammaridea into twenty-six families and in his later
work on the Gammaridea, 1906, he recognizes forty-one families.

I have followed pretty closely Stebbing’s later classification
in this paper and have attempted no revision of the group

whatever.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 15

PART I. AMPHIPODA.

KEY TO THE .SUBORDERS OF AMPHIPODA.

The: Amphipoda are divided into three suborders which may
be readily distinguished from each other.
A. Eyes large, covering nearly the whole side of the head; uro-

pods usually with laminate rami which form a tail fan with

LT SESS Olam aeeer eyev selves sh ttace i vareuta tess ots are oreaere tle ate HYPERIIDEA p. 44
AA. Eyes usually present but never enormously developed.
B. Abdomen well developed................-. GAMMARIDEA p. 47

BB. Abdomen rudimentary; body extremely slender
CAPRELLIDEA p. 174

ANATOMY
GENERAL ForM OF Bopy AND TELSON

In all the Amphipoda except the Caprellidea, the general
aspect of the body is quite uniform, being slender and slightly
tapering at each end and usually compressed laterally. In only a
few genera, such as Corophiuns, Siphonecetes, Unciola, and
Chelura, is the body cylindrical or depressed. The Lysianas-
side and Ampeliscide are the most compressed forms. The
Caprellidea are slender and threadlike.

The body is divided into three regions: the head or cephalon,
the thorax, and the abdomen. The head never exhibits its
segmental structure and the number of segments represented in
this region is still in question; it is probably seven. The thorax
is made up of seven segments, and the abdomen of six, exclusive
of the telson, which is probably not of the nature of a regular
segment of the body. The abdomen always is made up of three
freely articulating segments anteriorly, followed by three which
are never very movable and may suffer more or less fusion; thus
the fourth and fifth segments are fused in Dexamine and
Ampelisca and the fourth, fifth, and sixth are consolidated in
Chelura terebrans. This fusion, however, is of no great system-
atic value, since in different species of the genus Corophium,
for example, the last three segments may be either fused or all
distinct. In the Caprellidea the abdomen is very rudimentary and
is generally devoid of any indication of segmentation.

16 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

The head is always quite free from the thorax except in the
Caprellidea, where it is fused with the first thoracic segment.
It is largest in relation to the rest of the body in the Hypertidea
and smallest in the Caprellidea; it is always longer than the first
segment of the thorax in the Gammaridea.

The anterior margin of the head may be prolonged in front
to form a rostrum between the bases of the first antenne.
Usually the rostrum is an inconspicuous, pointed process, but in
some genera it may form a hoodlike projection over the basal
joints of the antenne as in Harpinia, Phoxocephalus, and Para- -
phoxus. ,In Siphonecetes the rostrum is spiniform; in
Dexamine and Epimeria it is curved ventrally. In the Ampelis-
cide the first antenne are so closely appressed that the rostrum
is wanting.

The anterior margin of the head, between the bases of the
first and second antenne projects forward as the interantennal
lobe, which is usually semicircular but may be acutely pointed
or variously modified. In Haustorius, Sympleustes, and Dex-
amine, the interantennal lobes are acute. The Ampeliscide are
peculiar in the great distance that separates the first and second
pairs of antennze and the almost complete disappearance of an
excavation in which the latter articulate. Usually the second
antennz are joined to the head only slightly posterior to the
first pair; but in those forms in which the second antenne are
more or less pediform, the front margin of the head may be
deeply excavated as in Ischyrocerus, Jassa, Ericthonius, Coro-
phium, and Unciola.

Eyes are usually present and compound. In a few species
they may be lacking, as in Harpinia plumosa and Stegocephalus
inflatus, or imperfectly developed, as in Phoxocephalus holbélli
and Haustorius arenarius. In most of the C&diceride the eyes
are situated so far dorsally that they are almost in contact with
each other. The Hyperiidea have very large eyes that cover the
whole side of the head, but in the Gammaridea the eyes are never
very enormously developed. It is only in the Ampeliscide that
we find the one pair of compound eyes generally present in the
Amphipoda replaced by two pairs of eyes provided with simple
corneal lenses.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 17

The segments of the thorax increase gradually in length from
the anterior end to the posterior, except in Harpinia, where the
last segment of the thorax is shorter than the preceding on
account of the reduction of the last pair of thoracic legs.
Although typically the dorsal region of the thoracic segments is
smooth and evenly rounded, in a few cases it may be produced
to form a keel as in Epimeria and Paramphithoe.

The first three segments of the abdomen are always in the
Gammaridea deeper than those of the thorax and have the
lateral margins prolonged downwards to form pleura; the last
three segments are small and do not have pleura. The dorsal
region of the abdominal segments, like the thoracic, is usually
evenly rounded, but more frequently than in the thoracic seg-
ments, it may exhibit a keel or crest as in Apherusa gracilis, In
Ampelisca spinipes and Byblis serrata the fourth segment bears
a prominent keel which ends abruptly posteriorly. The first four
segments of Calliopius leviusculus are quite characteristically
raiséd posteriorly to form rounded keels, while in Dexamine thea,
these segments are prolonged posteriorly to form sharp, spiniform
projections, and in Carinogammarus the first three segments only
are similarly produced. Many of the Lysianasside and Ampelis-
cide exhibit a depression on the dorsal side of the fourth abdom-
inal segment which is more pronounced in the male than in the
female. In Chelura terebrans, the third abdominal segment
bears a long curved process which extends posteriorly. The
posterior margins of the three posterior segments may be armed
with fascicles of spines, as in Carinogammarus and Gammarus,
or produced to form small spiniform projections, as in Mera and
Melita.dentata, or the spines may be confined to the fourth and
fifth segments, as in Leptocheirus pinguis.

The postero-lateral angles of the first three abdominal seg-
ments are usually evenly rounded but the third is especially
modified frequently. Thus in Ampelisca macrocephala, Unciola
irrorata, Sympleustes glaber, and Harpinia plumosa, it bears an
acute, slightly upturned projection, above which is a rounded
sinus, which in some cases may be followed by a rounded lobe.
In a few species the postero-lateral margins of the third abdom-
inal segment may be serrated, as in Batea secunda; or the second
and third may both be so adorned, as in Apherusa gracilis.

2

18 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

The telson has been regarded by some as representing the
last segment of the abdomen, but Della Valle and others regard
it as simply a development of the posterior end of the rectum, in
the nature of an anal valve, morphologically equivalent to the
upper lip which will be described below. The telson may have
the form of simply a thin oval projection as in Lystanopsis and
Calliopius. In Amphithoe, Grubia, Sympleustes, and Unciola
it is also a simple plate but somewhat thicker than in the pre-
ceding genera. In Microdeutopus the rectum passes directly
through the telson, which is undivided. The telson may be more
or less deeply divided into two lobes as seen best in the Gam-
maride where the lobes are usually rather widely separated from
each other and armed apically with a fascicle of spines.

APPENDAGES.,

Each segment of the crustacean body normally bears a single
pair of appendages upon the ventral side so that in those forms
in which two or more segments are fused together the number of
appendages affords a criterion of the fundamental segmentation.
In the head region of the Amphipoda, however, the difficulty of
determining the number of true segments lies in the fact that
an uncertainty exists regarding the homologies of some of the

appendages. According to most students of the group, the
head is made up of seven segments which bear the following
appendages from in front backwards: eyes, first or superior
antennz, second or inferior antenne, mandibles, first and second
maxilla, and maxillipeds. The last are regarded as homologues
of the first maxillipeds of the Decapoda, and as such are
fundamentally appendages of the thorax and not of the head.

The mouth parts form the buccal mass projecting from the
ventral side of the anterior end of the head. The buccal mass
is especially prominent in the Orchestiidea (Fig. 1). In the
Caprellidea the first gnathopod, owing to the fusion of the first
segment of the thorax with the head, appears to articulate with
the head and to be associated with the mouth parts.

Antenne.

The antenne may be very long, as in the males of many
CEdiceride, Phoxide, and Lysianasside in which they surpass

No. 26.] ARTHROSTRACA OF CONNECTICUT. 19

Fic. 1. Orchestia agilis.

the body in length; or they may be short as in Orchomenella.
The first antenne only may be extremely short, as in Orchestia
and the females of the Hyperiidea. The second antenne are
usually more constant in their size but they too suffer considerable
reduction in female Hyperiidea and may be very large as in
Corophium and Siphonecetes.

The first antenne are made up of a peduncle of three segments,
followed by a flagellum usually multiarticulate, and sometimes
also by a secondary or accessory flagellum. The first joint of the
peduncle is characteristically very stout in the Lysianasside.
The flagellum may be very short as in Orchestia. The accessory
flagellum is lacking in the Ampeliscide, Orchestiidz, Stenothoe,
Sympleustes, Calliopius, Pontogeneia, Dexamine, Batea, Ampli-
thoe, Ericthonius, Corophium, Siphonecetes, and Podoceropsis.
In some few genera like Grubia and Jassa, it is quite rudimen-
tary and may easily be overlooked. Particular attention is

20 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

called to Calliopius leviusculus, in which the process on the
distal end of the last segment of the peduncle of the first
antenne may be erroneously regarded as an accessory flagellum.

In the Caprellidea the number of segments in the flagellum
increases regularly with age, and a secondary flagellum is never
present.

The second antenne consist of a peduncle of five joints and
a flagellum which is usually multiarticulate. An accessory
flagellum is never present. Of the peduncular joints only the
last two are well developed, the first two are always very short
and the first is fused with the head. In the Orchestiide the
second joint is likewise fused with the head (Fig. 1). The
second joint is characterized by the fact that the antennal gland,
probably excretory in function, opens by means of a hollow
conical process on its lower side. This gland cone is conspicuous
in Melita and is very minute in Orchestia. In some species the
second antenne exhibit marked sexual differences. In Coro-
phium the peduncle of the male is much stouter and armed
with spiniform processes; in the. Lysianasside the whole
antenna is much longer than in the female, and in Ampelisca
the male has a row of tufts of specialized sensitive hairs on the
dorsal margin of the peduncle of the second antenna as well as
on the ventral margin of the first. The flagellum may be reduced
to a rudiment made up of only two or three segments, as in
Corophium and Siphonecetes, or may be very long and slender,
as in the males of the CEdiceride and Lysianasside, and Phoxus.
In the Caprellidea of the New England coast, the flagellum is
never more than biarticulate.

Both antenne may be provided with very curious, slipper- or
wineglass-shaped appendages known as calceoli, which probably
are sensory in nature. These are disposed along one margin of
the peduncles or at the distal ends of the flagellar segments.
They are seen in Calliopius, Pontogeneia, and the males of the
Ampeliscide.

Mouth Parts.

The mouth parts lie partly concealed by the projecting coxal
plates of the first gnathopods. As viewed from the side, however,
the mandibular palps and the maxillipeds extend forward beyond
the general outline of the mass. The mandibular palp is directed

No. 26.] ARTHROSTRACA OF CONNECTICUT. 21

forward and usually upward between the bases of the antenne,
while that of the maxillipeds extends downward and forward,
with the terminal joint bent somewhat toward the middle line.

The mouth is bounded above by the upper lip, which is a
broad plate, circular or oval in outline and continuous by its
front margin with the epistome. The epistome forms the ante-
rior, ventral surface of the head. The upper lip may form a
kind of rostrum projecting forward as in Ericthonius or it may
be small and vertical in position as in the Lysianasside.

The mandibles bound the mouth laterally and form the prin-
cipal chewing organs, being admirably adapted for tearing and
cutting by their strength and heavy calcification. In general
the mandibles are triangular in shape with the anterior margins
inclined toward the middle line, and, except in the Lysianasside,
bear several strong tooth-like processes. Behind this principal
incisive plate, or cutting edge, there is often a secondary one
movably articulating with it, which is weaker in structure, but
likewise usually denticulated. Posterior to the cutting edges,
the mandibles generally bear a molar tubercle having the form
of a cylinder or truncated cone, which is directed internally and
backward, and is armed distally with rasp-like teeth. The tubercle
is absent in the Lysianasside. ‘There may also be present a
palp, consisting of never more than three joints, which is inserted
towards the middle of the anterior surface. In the Orchestiide,
Dexamine, Stenothoe, and Caprella, the palp is lacking; in
Siphonecetes it is uniarticulate; and in Corophium it is made up
of two joints. In species having a triarticulate palp the first
joint is always short, except in the Hyperiidea, where it may be
somewhat elongated, but is never as long as the last two joints.
The terminal joint may be somewhat spatulate as in Ericthonius
but more generally it tapers to a slender point as in Gammarus
locusta and Elasmopus. |

The lower lip is inserted immediately beneath the mouth,
and is made up of two halves which are united on the middle
_line for a greater or less distance from the posterior end. Each
plate has a regular anterior margin of semicircular form except
in the genera Amphithoe and Grubia, in which there is a deep,
rounded sinus, making the plate bilobed. The postero-lateral
angles are always more or less prolonged to form the maxillary

—

22 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

processes. Posterior to the principal lamina there is a smaller
accessory one of oval form with its anterior margin entire.

The upper and lower lips are regarded as derived from folds
of the extreme anterior end of the esophagus and not as true
appendages. Hence they are not referred to definite segments
of the head.

The maxille differ from the mandibles in their laminar form.
The first maxille are more robust than the second and are pro-
vided with spines for tearing the food. The first pair are made
up of an inner and an outer plate and a palp. The palp never has
more than two joints, of which the first is shorter than the
second. The inner plate may be almost obsolete as in Coro-
phium and Siphonecetes, or large and oval and furnished dis-
tally and medially with plumose spines, as in the Gammaride.
In the Orchestiide, the inner plate is long and slender and armed
distally with two plumose spines. The inner plate is lacking
completely in the Caprellidea and Hyperiidea. The outer plate
is always larger than the inner. Its distal margin is armed
with a row of short spines of characteristic antler-like or comb-
like form which are masticatory in function. The palp articu-
lates with the outer plate and its apex usually projects beyond
the end of the outer plate. The palp is lacking in Orchestia and is
rudimentary in Hyale. In Dexamine and Phoxocephalus it is
of a single joint. The free distal margin is sometimes furnished
with setules, but more often it bears stout spines or is serrated.
The second maxillz are always small and flexible. They are
made up of an outer and an inner plate which bear sete on the
inner and distal margins.

The mavillipeds belong morphologically to the thorax, but
are discussed here, as is usual, in connection with the appendages
of the head. The maxillipeds cousist of an inner plate, outer
plate, and palp. The appendages of the two sides are fused
together on the middle line by the proximal joint. The inner
plates are formed by an anterior and median expansion of the
second joint, and the outer plates by a similar expansion of the
third joint; the palp is made up of the remaining joints which
may be as many as fout. In the Hyperiidea the second seg-
ments are fused together completely on the middle line and palps
are wanting; in the Caprellidea the fusion of the inner plates is

No. 26.] _ ARTHROSTRACA OF CONNECTICUT. 23

partial; but in all other Amphipoda the plates are separate and
palps are present. The plates are most highly developed in the
Lysianasside. They are obsolete in Stenothoe. The inner plates
usually bear numerous sete on their inner margins and may bear
tooth-like spines apically which are of use in mastication. The
outer plate is usually furnished with strong spines and sete on
the inner and distal margins. In Amphithoe and Grubia the
sickle-shaped spines on the inner margin gradually increase in
length toward the apex and become simple slender sete. The
first joint of the palp is always short; the second joint is usually
cylindrical, but in Orchestia it bears a distal laminar prolongation
resembling the inner and outer plates; the third joint is club-
shaped or ovoid; and the fourth joint is somewhat conical and
may be armed with a stout spine distally. In the genera
Haustorius, Oréhestia, and Talorchestia the palp is triarticulate,
but in all other genera, when present, it is four-jointed.

Gnathopods and Pereiopods.

In all the Amphipoda there are seven pairs of thoracic append-
ages, except in the Caprellidea, in the New England species of
which all traces of limbs of the third and fourth thoracic seg-
ments are wanting. The first two pairs differ greatly from the
others and are generally referred to as gnathopods; so that
the third thoracic limb becomes the first pereiopod. Each thoracic
appendage is made up of seven joints which, reckoning from the
proximal one, are designated usually as the coxal plate or coxa,
basal joint, or basus, ischium, merus, carpus, propodus, and
dactyl. In Haustorius the dactyls are wanting in the case of the
pereiopods, although present in the gnathopods. Batea is unique
in that the first gnathopod is reduced to a mere rudiment repre-
senting the coxal plate and basal joint.

The first two pairs of pereiopods, like the gnathopods, are
usually held flexed forward quite strongly at the joint between
the ischium and merus, and the dactyls are directed backwards.
They are usually of similar form and size and have slender basal
joints. The third, fourth, and fifth pereiopods are more or less
flexed backward at the joint between the ischium and merus and
the dactyls are directed forwards. The basal joints of the last
three legs are typically expanded to form flat plates.

24 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

The joints are all movable in a fore and aft direction, except
the first or coxal plate, which is attached to the thorax in such a
way as to be capable of a slight lateral movement only, and frora
the median side of which the succeeding joint of the pereiopod
arises. The ischium is always short, scarcely longer than broad
except in the second gnathopods of the Lysianasside. The
succeeding joints vary greatly in different species in both their
shape and size; the terminal one, however, is usually claw-like.

The coxal plates vary greatly in depth and length both among
themselves and in different species. They are very deep, for
example in Stenothoe, Metopa, Stegocephalus, and the Lysianas-
side, while in the Corophiide they are small and low, not forming
a continuous series of overlapping plates as is more common.
There is a gradual increase in size from the first to the fourth,
which is generally the largest. The fourth may be excavated at
the upper posterior angle to accommodate the coxal plate of the
fifth pereiopod, but in the following families it is not excavated:
Stenothoide, Aoridz, Photide, Amphithoide, Jasside, and
Corophiide. The fifth, sixth, and seventh coxal plates are often
considerably smaller than the preceding, diminishing posteriorly,
and are bilobed. Among the Caprellidea the coxal plates are
often absent and when present are extremely minute.

The gnathopods exhibit great differences in individual species
as well as in the two sexes and at different ages. The first pair
is smaller than the second except in the genera, Ampelisca,
Microdeutopus, Lembos, Unciola, and Leptocheirus, where the
condition is reversed. The propodus is usually subchelate;
that is, the posterior and distal margins form a palm against
which the dactyl strikes when flexed, so that the appendage is
adapted for grasping. The angle made by the posterior margin
and the palm is known as the prehensile angle and may be armed
with one or more stout spines. The dactyl may have its concave
margin modified by serrations or processes. In a few species
the dactyl does not close against the propodus, in which event
the gnathopod is known as simple. This is more frequently the
case with the first pair than with the second. Thus in Lysianop-
sis alba, Leptocherius pinguis, and the females of Talorchestia,
the first gnathopod is simple, and in Ampelisca spinipes, the
second is simple. Besides the simple and subchelate forms of

No. 26.] ARTHROSTRACA OF CONNECTICUT. 25

these appendages, there may also be the chelate type, in which
the propodus is prolonged at the posterior margin distally so that
the dactyl strikes against the anterior margin of this, as in the
pincers of the lobster or crayfish. The second gnathopod is
chelate in Lysianassa and in the females of Talorchestia and
Orchestia. In a few species the gnathopods are found to be
complexly subchelate, in that a process of the carpus becomes
involved in grasping. Thus in Microdeutopus, the first gnathopod
of the male, and in Ericthonius and Cerapus, the second pair is
complexly subchelate. Among the Caprellidea the second
gnathopods are, as a rule, inserted near the front margin, or at
least in front of the middle of their segment, although in the male
Caprella the insertion is very near the middle.

In a number of families the first and second pereiopods
possess peculiar glands situated for the most part in the basal
joints, but often extending into the distal joints as well, and
opening to the exterior at the apex of the dactyl, which is then
slightly truncate, or at a point just proximal to the tip. Such
forms as Ampelisca, Microdeutopus, the Amphithoide, Jasside,
and Corophiide, secrete by means of these glands a sticky sub-
stance which hardens quickly to form a thread. By means of this
secretion a tube is formed for concealment as will be described
below (p. 39).

In the native Caprellidea the first and second pereiopods are
entirely wanting, but the three posterior pairs are well developed
and subchelate. They increase in size from the anterior pair
to the posterior.

Abdominal Appendages.

The abdomen bears two quite distinct types of appendages,
and for this reason is frequently differentiated into an anterior
pleon of three segments and a posterior urosome. Each segment
of the pleon bears a pair of pleopods adapted for swimming,
each of which consists of an unjointed basal joint or peduncle
with two flexible, multiarticulate rami distally. These are pro-
vided marginally with long plumose sete. The two peduncles
are held together by a series of hooks, called coupling spines,
which are situated near the distal end. In Corophium the pedun-
cle is broadly, expanded medially but in other forms it is more
nearly cylindrical in form.

26 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

There are usually three pairs of uropods present. These
appendages are never very movable and are always directed
posteriorly, and are closely approximated. Like the pleopods
they are made up of an unjointed peduncle and two rami, although
in the Orchestiidz, and in the genera Unciola, Stenothoe, Siphon-
ecetes, Corophium, and Ericthonius; the terminal pair is uniram-
ous. The rami are usually uniarticulate although the outer one
may exhibit also a small terminal joint. The terminal uropods
often differ greatly from the preceding pairs in size and form.
In Ampelisca and the Gammaride they project considerably
beyond the others. In Melita the inner ramus is reduced to a
mere scale-like rudiment while the outer one is biarticulate.
Usually both the peduncle and the rami bear strong spines along
the upper margin and at the tip. In Leptocheirus, Microdeutopus,
and Grubia, the peduncle is prolonged beneath the attachment of
the rami to form a long, slightly upturned, spiniform process. In
Unciola the peduncle is produced into a lobe as long as the single
ramus.

The rami may be lanceolate or flattened, as is seen best in
the Gammaride, or they may be cylindrical or conical with re-
curved spines at the apex, as in Jassa, Ischyrocerus, Grubia, and
AmpiIuthoe.

In Chelura the uropods are highly specialized. The first pair
are of the typical form, but the second pair lie well on the dorsal
side of the abdomen; the peduncle bears a very large plate-like
expansion inedially and the rami are scarcely longer than wide;
the terminal uropods are very large, with the outer ramus ex-
tremely long, especially in the male, and the inner ramus minute.

Owing to the extremely rudimentary condition of the abdomen
in the Capreilidea, the appendages are greatly reduced. In
4Z ginella the first pair of appendages are biarticulate and the sec-
ond pair are uniarticulate. In Caprella the males have a biarticu-
late pair in front and a thick uniarticulate pair behind. In the
females the limb-like (first) pair are reduced to simple
eminences bearing a few sete.

SENSE ORGANS.

Besides the eyes, which have already been discussed, the sense
organs of the Amphipoda consist of various filiform and special-

No. 26.] ARTHROSTRACA OF CONNECTICUT. | 27

ized processes of the integument, whose exact functions are still
largely conjectural. When a foreign chemical substance is*placed
in a vessel containing Amphipoda, the antennz are waved vigor-
ously, which may point towards the conclusion that on these
appendages are smelling or tasting organs. The delicate thread-
like setee noted frequently on the principal flagellum of the first
pair of antenne are called olfactory hairs. The calceoli, which
occur in forms like Calliopius, are conical vesicles attached by
their apices to the general surface of the skin. They have been
called by Leydig “ slipper-shaped”’ structures, but with greater
propriety they might be compared to wine glasses. Their func-
tion is wholly unknown.

INTERNAL ANATOMY.
The nervous system consists of two symmetrical ganglionic
chains, united at intervals by commissures, and lying on the
EVO AWT4

| Aepalo-pancreas
! Ms . *
ene ilesting Tess

CPT
Sy Stomach

Fic. 2. Internal Anatomy, after Stebbing.

ventral side of the alimentary canal, except at the extreme ante-
rior end, where the ganglia are on the dorsal side (Fig. 2).
The supraesophageal mass is made up of two halves, separated
by a deep median groove, and consists of two large cerebral lobes,
as well as a pair of ganglia, which give rise to the optic nerves,
and another pair giving rise to the antennal nerves. Beneath
the esophagus and connected with the brain by commissures
around it, lies the subesophageal mass, which gives off nerves
to the mouth parts, and represents the consolidated ganglia of
the segments to which the mouth parts belong. The sub-
esophageal ganglia are continuous posteriorly with the sub-
intestinal ganglionic chain. This consists of a pair of ganglia,

28 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

fused together in the middle line, for each body segment except
the last three, in which the ganglia are fused to a single mass.
In the Caprellidea the ganglia of all the abdominal segments are
fused together.

The alimentary canal consists of a straight tube of uniform
diameter, except in the anterior portion, where it is dilated to
form the stomach. The latter opens anteriorly by a narrow
esophagus, which is curved ventrally. The mouth is bounded
above and below by the upper and lower lips. The stomach is
ovoidal in form and of very complicated structure. As in all
the Malacostraca, a gastric mill is present which includes both a
grinding and a straining mechanism. The midgut extends from
the posterior end of the stomach to the last thoracic segment.
Extending forward on the dorsal side of the stomach from the
anterior end of the intestine is a so-called pyloric caecum which is
single in the Gammaridea but double in the other groups of
Amphipoda. Arising likewise from just behind the stomach
are the hepato-pancreatic ceca which extend to a considerable
distance posteriorly, lateral and ventral to the intestine. Typically
there are four of these tubes present, but in Corophium arid
Siphonecetes a single pair is present. In addition to these
ceca there is also a “rectal gland,” of cecal form, extending
forward and dorsally from the anterior end of the hind gut.
This rectal gland probably corresponds to the Malpighian
tubules of insects and functions as an excretory organ, accord-
ing to W. B. Spencer (Quar. Jour. Micro. Sci., ser. 2, vol. 25,
pp. 183-191, 1885). It is confined in most Gammaridea to the
last three abdominal segments. The intestine opens to the ex-
terior through the anus which lies just below the telson except
in the Photidz, in which the telson is hollow and is traversed by
the posterior end of the hind gut.

The circulatory system consists of a heart, arteries, and
lacune or sinuses. The heart is tubular in form, open at both
ends, and situated in the dorsal part of the thorax immediateiy
beneath the integument, and extending as far back as the sixth
thoracic segment. On the lateral sides of the organ are three
pairs of openings, called ostia, which are oblique slits, guarded
by valves which open inward. In the Hyperiidea there are two
pairs of ostia usually and in Corophium the number is reduced

No. 26.] ARTHROSTRACA OF CONNECTICUT. 29

to a single pair corresponding in position to the last one of
other forms. The arteries are reduced to an anterior and a
posterior aorta, the openings into which from the heart are
guarded by valves opening outward. The posterior aorta les
close against the intestine; the anterior one breaks up principally
about the nervous matter of the head. The principal lacune are
the pericardium and the ventral lacuna; they have no walls of
their own but are simply the spaces between other organs through
which the blood courses somewhat irregularly.

Internally the Amphipoda and Isopoda differ most strikingly
as regards the circulatory system. In the latter group the heart
lies principally in the abdomen and ends blindly behind. Besides
the anterior aorta, like that of the Amphipoda, there are five
pairs of arteries extending forwards. On the ventral side of
the body is a large blood sinus which is paired in the thorax but
single in the abdomen. Five pairs of veins convey blood from
the pleopods, which are respiratory in function in the Isopoda,
to the pericardial lacuna. In the Isopoda the arterial system is
much more complete than in the Amphipoda, where the lacune
are relatively more extensive. There is accordingly a more per-
fect separation of arterial and venous blood in the Isopoda.

The rapidity of the pulsations of the heart is considerable. Ir.
young specimens of Microdeutopus Della Valle found the rate
to be two hundred per minute.

Closely associated with the difference in the position of the
heart in the Amphipoda and Isopoda is that of the respiratcry
organs. In the former group the gills have the form of flattened
oval sacs, depending from the upper posterior corner of the
coxal plates, internal to the principal axis of the limbs. (Figs. 3
and 26.) The gills are confined to the last six thoracic append-
ages. Ina few genera the last pair of pereiopods also lack gills.

In Ampelisca and Corophium the second gnathopods, of the
females only, are devoid of these appendages and in Ericthonius
and Cerapus this gill is absent in both sexes. The gills are ex-
ceedingly large in Gammarus, but in Orchestia they are very
much reduced, in accordance with the semiterrestrial habit of
the genus, and are twisted on their long axes instead of being flat
plates parallel to the coxal plates. The anterior gills are usually
larger than the posterior ones.

30 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

nerve cory,

coslegule

Fic. 3. Cross section through a female Amphipod.

The testes are small, slender, fusiform, paired organs which
lie directly below the heart and dorsal to the intestine. These
organs taper posteriorly to two delicate tubes, the ejaculatory
ducts, or vasa deferentia, which open by papilla on the ventral
side of the last thoracic segment. In the breeding season these
papilla enlarge considerably to form copulatory organs (Fig. 31).
The glandular portion of the testes usually lies behind the
second and in front of the fifth segment of the thorax. Its
anterior end is very attenuated and serves as a kind of ligament
to hold the organ in place.

In the female the ovaries have the same position as the
testes in the male but are somewhat longer. In form the ovary
is irregularly cylindrical and when ripe may be more or less
inflated. The oviduct opens from the lower outer surface of the
Ovary at a point corresponding to the fifth thoracic segment and
continues as a simple straight tube to the exterior at the base
of the fifth coxal plate.

Usually there are four pairs of marsupial plates or odstegites
borne on the second, third, fourth, and fifth thoracic legs, but
in some species there are six pairs attached to the last six legs,
and in the Caprellidea there are only two pairs, belonging to the

No. 26.] ARTHROSTRACA OF CONNECTICUT. 31

third and fourth segments. They are inserted on the inner
surface of the coxal plates except in the Caprellidea and
Phronimide where the attachment is directly to the ventral wall
of the thorax. The insertion is nearer the middle line than the
gills, so that when the brood pouch is filled with eggs the gills
remain free to oscillate and receive fresh water.

In form these plates are rather long, tongue-shaped plates the
margins of which are always provided with numerous long, slen-
der prolongations like exceedingly flexible sete. These prolonga-
tions intertwine with each other so that the lamelle form a
kind of basket which receives the eggs from the oviducts.

SEXUAL DIFFERENCES.

The sexes of the Amphipoda are always separate. Usually
they are readily distinguished by the large marsupial plates, or
oostegites, of the females which support and protect the eggs
and immature young. Besides this difference in the two sexes,
the males are usually larger than the females and are provided
with more sensory spines and sete. It is in the form of the
second antenne and gnathopods, however, that the secondary
sexual characters are most conspicuous. In striking contrast to
the general rule that the second antenne of the males bear more
sete than those of the females is the case of Corophium, in which
the second antennz of the male have none on the peduncle while
those of the female have many. On the first antenne of Am-
pelisca and the Lysianasside, calceoli are present in the males
but not in the females.

The first gnathopods of Orchestia, Cerapus, and Microdeuto-
pus are of vastly different form in the male and female, as may be
seen by reference to the descriptions of the forms in question.
In other genera, like Amphithoe, Hyale, and.Gammarus, for
example, the sexual differences in the first gnathopods are in-
significant.

The second gnathopods are strikingly different in the two
sexes in Talorchestia, Orchestia, Metopa, Elasmopus, Amphithoe
longimana, Jassa, Ischyrocerus, and Ericthonius.

In Chelura terebrans, the second and third uropods are quite
distinct in form in the two sexes; the second pair is provided
with long sete in the male which are lacking in the female; the

32 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

third pair has a foliaceous outer ramus in the female, and a
much larger styliform one in the male. In this species, there is
great difference between the male and the female in the length of
a long styliform process extending backwards from the mid-dor-
sal line of the third abdominal segment.

The secondary sexual characters are not acquired completely
until maturity is reached. The female form may be looked upon
as the more primitive, for the young, when first escaped from the
egg, generally resemble the female rather than the male. In
examining a large number of specimens of Orchestia agilis from
Woods Hole it was found that all individuals up to about 7 mm.
in length have gnathopods like the female, and in two or three
individuals about 7.5 mm. long the first gnathopods were of the
male form, and the second pair, of the female. The gnathopods
were of exactly the same form as those of the respective adult
forms and showed no sign of transition between the two.
Although it has been known that the male characters are acquired
gradually, there have been no accounts of the condition in which
one pair of appendages is male and another female.

SP PAI

The Amphipoda of Connecticut are in general of small size.
The largest species of the coast is probably Gammarus locusta
a few specimens of which, collected at New Haven, had a length ©
of 30 mm. As in many other groups of animals a larger size is
attained in the Arctic regions or in the cold waters of great
depths. Thus Sars records a length of 48 mm. for Gammarus
locusta in the Arctic regions, and Professor S. I. Smith (Ann.
and Mag. Nat. Hist., ser. 5, vol. 14, page 181, 1884) records an
Amphipod, Eurysthenes gryllus Boeck, dredged by the “Alba-
tross”” in i917 fathoms which had a length of 4% inches. This
probably represents the largest known member of the group. At
the other extreme of size are Stenothoe, 2mm., Dexamine thea,
3 mm., and Corophium cylindricum, 3-4 mm. in length.

COLOR.

The colors of the Amphipoda are frequently quite brilliant in
life, but with scarcely an exception specimens bleach to such an

No. 26.] ARTHROSTRACA OF CONNECTICUT. Be

extent in preservatives that at best only a few spots of pigment
of a chocolate brown or black remain.

The usual color is whitish or grayish but a few of the native
species exhibit very characteristic pigmentation. Leptochetrus
pinguis, for example, retains its dark chocolate spots even after
years in alcohol. Unciola irrorata is mottled with bright crimson.
Jassa marmorata is of a reddish ground color, interrupted by large
lighter spots.

Many species also exhibit great variations in coloring.
Amphithoe longimana may vary from bright green to bluish
green, or nearly colorless, and also from light to dark reddish
brown.

According to Holmes (Biol. Bull., vol. 2, p. 181, 1902) the
color of some individuals is by no means constant. In Amphithoe
longimana, the species studied by Holmes, the color is due
especially to the pigment cells although the color of the blood
and tissues, the contents of the alimentary canal, and the color
of the reproductive glands also affect that of the body, as scen
by the naked eye. In one specimen the general blue color of the
blood and tissues after five days had disappeared, the green be-
coming more nearly like the typical green of other forms, and by
the ninth day the tissues were whitish. This whitening took
place in spite of the fact that abundant quantities of green alge
were consumed.

The most important factors in determining the color changes
in Amphithoe longimana are the reddish-brown pigment spots
which are scattered all over the body and on most of the append-
ages, especially near the proximal end’ These pigment spots
change very slowly, generally requiring several hours to effect a
change from the expanded to the contracted condition.

JaRAN EIT yalely

The Amphipoda are exclusively aquatic in their habitat, and
very generally they are marine. It is only among the Orchestiide
that there is an approach to a terrestrial habitat. Talorchestia
longicornis occupies a zone of the beach a short distance above
high-water mark but sinks its burrows to a depth at which the
sand is always moist. Orchestia palustris and O. agilis also live

near high-water mark, the latter occupying a lower zone than the
3

34 CONNECTICUT GEOL. AND NAT. HIST, SURVEY. [ Bull.

former. Orchestia palustris prefers mud, and as it is able to
survive exposure to brackish or nearly fresh water, it is often
found in salt marshes and may find its way to some distance
from the shore. Della Valle mentions O. gammarellus, in which
species he includes O. palustris, as occurring several kilometers
from the sea shore at Naples. Allorchestes littoralis also occurs
high upon the beach, according to Holmes. With these few
exceptions, however, the Amphipoda are thoroughly aquatic.

In New England there are only three species which occur 1n
fresh water: Crangonyx tenuis, which was found by Smith in
wells at Middletown, Dikerogammarus fasciatus, and Hyalella
knickerbockert.

Dredging operations have been so incomplete in the waters
of Long Island Sound within the bounds of the State that it is
impossible to generalize from these data alone. The extensive
observations made in the nearby waters of Vineyard Sound and
Buzzards Bay by Verrill and Smith and also by Sumner, Osburn,
and Cole may, it would seem, be extended in the most general
way to the shores and waters of Long Island Sound.

The following species are known to occur at the surface and to
be taken in towing:

Allorchestes littoralis Elasmopus levis
Ampelisca macrocephala Gammarus annulatus
Amphithoe longimana G. locusta

A. rubricata Grubia compta

Batea secunda Hyperia galba

Byblis serrata Leptocheirus pinguts
Calliopius leviusculus Microdeutopus gryllotalpa
Carinogammarus mucronatus Paraphoxrus spinosus
Corophium cylindricum Pontogeneia inermis

Dexamine thea

The following species are found most commonly in eel-grass
and mud:

Amphithoe longimana Grubia compta

A. rubricata Leptocheirus pinguts
Caprella geometrica Lysianopsis alba
Cartnogammarus mucronatus Microdeutopus gryllotalpa

Elasmopus levis

No. 26.] ARTHROSTRACA OF CONNECTICUT. 35

The following species are found on piles among Hydrords,
sponges, etc. :

Allorchestes littoralis Grubia compta
Caprellidze Melita nitida

Corophium cylindricum Microdeutopus gryllotalpa
Elasmopus levis Stenothoe cv\'pris
Gammarus locusta S. minuta

On sandy shores the more common species are the following:

Allorchestes littoralis T. megalophthalma
Orchestia agilis Haustorius arenarius
Talorchestia longicornis Unciola irrorata

The more common species that are found on rocky shores
between high- and low-water marks, and often in the greatest
abundance, are the following:

Orchestia agilis Elasmopus levis
O. palustris Gammarus marinus
Gammarus locusta Unctola irrorata

Amphithoe rubricata

O. agilis is especially abundant beneath masses of decaying
sea weed. Gammarus locusta is more common under stones and
among rockweed at low-water mark. <Amplithoe rubricata
abounds in similar situations but apparently prefers Ulva to
rock weed. Unciola irrorata is found only at low-water mark.

MOVEMENTS.

In general the Amphipoda are very agile and energetic except
those species which inhabit tubes, usually of their own construc-
tion, or lie buried in the sand or in excavations of wood, like
Chelura.

The most constant and uniform movement: is that of the
pleopods, by which a current of water is constantly passed
forward over the gills. Besides these movements it has been
observed in some species that the mouth parts move more or less
regularly as if the animal were eating although there may be
no food whatever in the water. In eating, the mouth parts of
Orchestia agilis vibrate about 120 times a minute.

36 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Although the Amphipoda possess three different kinds of
locomotor organs, the pereiopods, pleopods, and uropods, which
are used respectively for crawling, swimming, and leaping, it is
only in a few species of Orchestiidz that we find all three methods
of locomotion employed. Unlike many of the higher crustaceans
locomotion is always forward. The most general method is
swimming. In order to obtain a start in swimming the animal
usually extends the abdomen with some vigor — this part of the
body being carried, when the animal is at rest, curled up beneath
the body —and then maintains its motion by means of the rapid
vibration of the pleopods. In swimming vertically, however,
the abdomen frequently aids in the propulsion of the body, as
in starting. While swimming, the body is well straightened, the
antennz are held out in front of the body and move slightly as
if exploring, and the pereiopods are held directed backwards.
The animal seems to have some difficulty in maintaining its
balance for it frequently rolls over and swims with its back or
one side or the other downwards.

In walking or crawling there are two quite distinct methods.
In those species whose bodies are depressed like Corophium, for
example, the body is easily maintained in an upright position and
supported by the pereiopods. Where the body is strongly com-
pressed, however, the upright position is with difficulty held and
the last two pairs of pereiopods are bent outwards to brace the
body. In these forms it is far more usual for the animal to lie
on its side and progress by the alternate flexion and extension
of the body with the corresponding movements of the pereiopods.

Jumping is resorted to only by Orchestia and Talorchestia,
and in these forms only when the animal is startled and must
escape quickly. This act is accomplished by the uropods and the
abdomen which is extended suddenly. Orchestia agilis can easily
spring more than a foot into the air. The jumping is usually
aimless and as a result the animal frequently falls upon an
unfavorable spot.

In climbing over alge and other irregularities of the bottom,
many species employ their antennz as hooks for pulling the body,
but the gnathopods are more generally used for this purpose.

Burrowing has been studied most carefully by Miss Small-
wood in Talorchestia which lends itself to the observation of this

Nor 26:] ARTHROSTRACA OF CONNECTICUT. 37

process by its preference when in a glass receptacle for burrowing
along the side of the glass. Talorchestia burrows only in fine,
loose sand, and when coarser sand or shell fragments are
encountered below the surface the animal ceases to burrow.
The second antennz are bent back sharply at the second joint and
the head is pushed into the sand. The grains of sand are passed
back from the first gnathopods to the anterior pairs of pereio-
pods while the body is largely supported by the posterior pairs.
The sand thus accumulates behind the body, which is more or
less curled. At intervals the body is vigorously straightened and
the sand projected some centimeters. As the burrow deepens,
the sand is simply pushed behind the body by the pereiopods and
the hole is closed.

FOOD.

The Amphipoda, so far as our knowledge goes, are voracious
feeders, consuming all kinds of animal and vegetable maiter,
whether in the fresh condition or putrid. It-is only rarely that
they have been known to attack and consume living animals, but
freshly killed animals are eagerly fed upon. By roughly estimat-
ing the amount of fecal matter discharged by a single Amphithoe
supplied with an abundance of food (Ulva), Holmes concluded
that in twenty-four hours about one-tenth of the body weight was
consumed. The greater part of the food of the Amphipoda,
probably because of its usually greater abundance, is vegetable;
but molluscs, fish, and annelids as well as dead individuals of
their own species are quickly consumed. The cast skin is fre-
quently eaten, for in aquarium jars in the laboratory usually only
small fragments of the molted skin are observed.

The Amphipoda are not at all discriminating in their choice
of food; bleached fronds of Ulva are ‘consumed as readily as
fresh green ones which may be lying beside them, and paint-
covered straws from old brooms and paper will be eaten when
there may be an an abundance of fresh sea weeds and animal
tissues at hand.

In eating, the food mass is held by the gnathopods and anterior
pereiopods and chewed directly without first being torn apart by
the gnathopods. When alge like Ulva are eaten, the frond is
gnawed from the edge into an irregularly shaped excavation of

38 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

rather smooth contour or from a central point where it is
puckered or folded.
ENEMIES.

The principal enemies of the Amphipoda are undoubtedly fish.
As noted in the section on the economic importance of the group,
the Amphipoda form a very extensive source of food. for many
of our most highly valued fishes. Even the shore-inhabiting
species, like Orchestia, frequently fall prey to Fundulus which
come with the tide into every place where there is enough water
to cover them and search for every possible material for food.
The Amphipoda are usually in concealment when the tide is high
but when one leaves its retreat it forms a tempting morsel for
a fish. Besides fishes, the shore-inhabiting species must also be
destroyed by birds. Although this has never actually been
observed, forms of life far more active than the Amphipoda
have frequently been seen to be pursued by birds in the same
spots occupied by Orchestia and similar species. Miss Small-
wood also describes an encounter which she observed between
a half grown Orchestia palustris and one of the staphalinid
beetles, in which the latter was victorious. The spiders, which
occur in the same localities and occupy the same retreats as
individuals of this species, must also serve to keep down the
numbers.

RESISTANCE TO ADVERSE CONDITIONS

The generally wide distribution of the Amphipoda may be
partly accounted for by their power of resisting unfavorable
environmental conditions. Many marine, as well as fresh-water,
forms are able to survive under conditions which are fatal to
almost all other groups. In examining material collected along
the shore, it is frequently noticed that after molluscs, actinians,
and worms decay, the Amphipoda still survive.

Talorchestia, though not living in water normally, is dependent
nevertheless upon it, for when placed in perfectly dry sand,
specimens died in less than seven hours, while those placed in
partially moistened sand in the laboratory survived ten or twelve
days; when the sand is kept completely covered with water, it
has been found that this species dies quite soon. Orchestia
palustris may remain submerged for days without fatal results

No. 26.] ARTHROSTRACA OF CONNECTICUT. 39

and yet the species normally abounds in fairly dry surroundings
where individuals run about im the dry grass for several hours
at a time. Specimens of Orchestia agilis I have found surviving
after several hours on a dry laboratory floor in the summer.

The shore-inhabiting forms must necessarily be able to endure
considerable changes in the density of the water. Orchestia
palustris will bear an exposure for several hours to fresh or
brackish water. Talorchestia, according to Miss Smallwood, will
bear exposure to spring water for six and a half hours without
fatal results.

MOLTING.

The frequency with which the Amphipoda molt is not known
with any degree of certainty. Holmes found that in Amphithoe
of the usual size two successive molts took place in seven or eight
days. The frequency decreases as the adult size is gradually
attained.

In the process of molting the skin splits transversely along
the line joining the head and thorax and on either side of the
thorax between the upper margins of the coxal plates and the
lower margins of the thoracic rings. The head and antenne are
pulled backwards and the posterior part of the body is pulled
forwards, the old skin remaining intact except along the splits
just mentioned.

The process may be completed in a quarter of an hour or so,
or it may be prolonged over several days. Holmes notes one such
case in which the animal died before the molt was completed.
Immediately after molting, the animal is rather quiet but in a
short time, a quarter of an hour, after the old skin has been shed,
it assumes its ordinary activity. The antenne may become broken
during this process but no other appendages have been observed
to be lost at this time. .

NESTS AND NEST-BUILDING.

Those species of Amphipoda which possess glandular pereio-
pods habitually occupy tubes which serve as hiding places for
them and from which it is rather difficult to drive them. Usually
these tubes are cemented to some solid object, but Cerapus
tubularis carries its tube about with it. These tubes are com-
posed of a felt-like mass of fine threads which are secreted by

40 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

the glands of the pereiopods and spun as it were into the
characteristic fabric. As the secretion emerges from the open-
ing at the tips of the pereiopods it hardens immediately as in
the spider’s web. Bits of algze and grains of sand are frequently
woven into the tube which is thus rendered more inconspicuous.
Smith has observed that in Microdeutopus bits of fecal matter
are also worked into the web, but Holmes finds that Amphithoe
does not use excrement to increase the tube but passes it out of
the nest; accumulations of it usually being seen at both ends of
the tube.

The tubes are usually open at both ends and of uniform
diameter throughout. Their length is as a rule considerably
greater than that of the animal.

In constructing a tube, the first two pairs of pereiopods are
seen to be in rather rapid motion, passing back and forth over
the space which the tube is to occupy. By rolling over and con-
tinuing this motion the tubular form is attained.

Amphithoe and various other species frequently leave their
nests; they seem, however, to show no particular preference to
return to those of their own making, but slip into any one that is
unoccupied or proceed to build another, which is done in a re-
markably short time, often in less than half an hour. Unciola
usually inhabits a tube, but has no spinning glands in its pereio-
pods and has never been observed to weave a web for itself.

The tube-dwelling forms habitually remain in their tubes
with only the head and antenne thrust out. When disturbed
Amphithoe retreats further into its tube and seeks safety in flight
only when the intruding object is so persistent as to prevent
further retreat into the depths of the tube. Holmes has observed
Amphithoe dart out for food without letting go of its tube and
quickly retract itself with the food in its gnathopods and devour
it at leisure within its tube.

The instinct to build tubes develops very early in life. A few
days after leaving the brood-pouch, the young set about construct-
ing nests like the adults, and exhibit precisely the same reactions
to stimuli and habits.

BREEDING HABITS.

The eggs are discharged from the openings of the oviducts,
those from each orifice, according to Della Valle, becoming

No. 26.] ARTHROSTRACA OF CONNECTICUT. 41

enveloped in a gelatinous capsule, so that when removed from
the marsupium each egg mass retains its form. The young
remain in the marsupium for some time after their escape from
the egg and in some species it has been noted that the young
return to the brood-pouch when forcibly removed from it.
Observations are scarce regarding the length of time that the
brood-pouch is occupied by the eggs and young, but in Orchestia
palustris it may not be more than two weeks. Some specimens of
Gammarus locusta kept in the laboratory were found to retain
the eggs and young from two to two and a half weeks.

From observations made on Amphipoda collected at Woods
Hole as well as at Noank and New Haven, females were found
carrying eggs on the following dates:

Hyperia, Apr. 4 to June 3.

Orchomenella pinguis, Jan. 23.

Ampelisca spinipes, July 13 to Aug. 15.

Byblis serrata, July 23.

Stenothoe minuta, Aug. and Sept.

Lafystius sturionis, Oct. 20 and Nov. 24.

Calliopius leviusculus, Jan. 11, 22; April 1, 20, 27; May 6,

2m haly agin: Aue. 6,°205°Dec. 11, 25,

Sympleustes glaber, April and July 13.

Batea secunda, Aug. 23.

Pontogeneia inermis, July 13.

Melita nitida, Aug. 17.

Elasmopus levis, Aug. 15, 17.

Gammarus locusta, May 3; July 31; Aug. 6-10.

G. annulatus, Mar. 6; Apr. 1, 20, 27; May; June 21.

Carinogammarus mucronatus, Aug. 14, 17.

Orchestia agilis, May ; June; first two weeks of July; Aug. 13
very few eggs.

Orchestia palustris, July 9, 21.

Talorchestia longicornis, June 14 (according to Bumpus, eggs
in a late stage of development) to Aug. 13. (Miss
Smallwood found the young free in the sand at Cold
Spring Harbor and very few females bearing young
by the end of July.)

Allorchestes littoralis, Aug. 18.

Microdeutopus gryllotalpa, July 13 to Aug. 18.

42 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Leptocheirus pinguis, Aug. 10 to 18.

Amphithoe rubricata, Aug. 6 to 17.

A. longimana, Aug. 13 to 17.

Grubia compta, July and August.

Jassa marmorata, July 31 to Aug. 19.
Ischyrocerus anguipes, April and July 17.

Cerapus tubularis, July 4, 21

Ericthonius rubricornis, Aug. 10.

Unciola irrorata, May 1; July 13; Aug. 9, 18.
Corophium cylindricum, Jan. 5; July 17 to 21; Aug. g to 2g.
Caprellide, March, July, August, and September.

The number of eggs deposited at one time varies greatly in
different species. Observations have been made on a very few
species so that our knowledge is limited. Orchestia agilis carries
from seven to fifteen eggs, while one specimen of Calliopius
leviusculus, whose oostegites are unusually large (Fig. 17),
was found with nearly seventy eggs.

Copulation seems to be in most cases an act quite independent
of the sexual condition of the individuals, although females
bearing eggs in the marsupium are practically never found with
a male. Holmes has studied the copulating of several species
and finds that the recognition of the female by the male is purely
the result of chance which brings the two sexes into collision
with each other. That copulation takes place is due to the
difference in the reaction of the two sexes when in collision.
When two males collide both become active and for a few
moments strive to grasp each other but because of the mutual
activity fail to accomplish their end; when two females chance
to meet, both roll up and become quiescent and in a few moments
swim about as-before. When, however, opposite sexes meet, both
pursue the tactics described above with the result that the male
grasps the female and swims off with her lying perfectly passive,
her body strongly flexed. In all the species observed the female
remains inactive save for the movement of the pleopods to main-
tain a respiratory current.

In copulation the male ordinarily retains his hold of the
female by hooking the dactyls of his pereiopods beneath the
edges of the coxal plates of the female; the gnathopods are used

No. 26.] ARTHROSTRACA OF CONNECTICUT. 43

apparently only when a sudden disturbance renders the hold of
the male insecure. The male carries the female thus for several
days or probably much longer, and can with difficulty be
separated without injuring him.

Deposition of the eggs and fertilization have been observed
rarely. Della Valle has described the process fully in Gammarus
pungens, a fresh-water species of Europe. Deposition of the
eggs takes place soon after molting and while the eggs are being
discharged the male slips around the female so that their two
heads are still pointing in the same direction but their ventral
sides are directed toward each other and the openings of the
vasa deferentia lie close to those of the oviducts. In this posi-
tion the spermatic fluid is discharged over the eggs and fertilizes
them. Immediately following the ejaculation the male returns
to his former position with reference to the female.

BISELOM SPECIES:

In the following list an * indicates that a species is likely to
be met with in the State although up to this time it has been un-
reported. A + indicates that a species is found in fresh water.
Heavy-faced type indicates a species unreported hitherto from
New England.

HY PERIIDEA A. spinipes Boeck

Hyperia galba (Mont.) Byblis serrata Smith
GAMMARIDEA, HAUSTORIIDA
LYSIANASSIDE Flaustorius arenarius (Slabber)
Lysianopsis alba Holmes PHOXOCEPHALIDE
Orchomenella pinguis (Boeck) Phoxocephalus holbolli (Kr.)
*Tmetonyx cicada (Fabr.) Paraphoxus spinosus Holmes
T. quadratus sp. nov. *Harpimia plumosa (Kr.)

*Hippomedon serratus Holmes

: ETOPID
*Anonyx nugax (Phipps) ‘i

*Metopa grenlandica Hansen

STEGOCEPHALID
*Stegocephalus inflatus Kr. eo
Stenothoe cypris Holmes
AMPELISCIDE
. “7: 5. minuta Holmes
Ampelisca macrocephala Lill}.
*A4. compressa Holmes LAFYSTIID

*A, agassizi (Judd) *Lafystius sturionts Kr.

44

CEDICERID/E

CONNECTICUT GEOL. AND NAT. HIST. SURVEY.

| Bull.

tHyalella knickerbockeri (Bate)

*Monoculodes edwardsi Holmes Allorchestes littoralis Stim.

CALLIOPIID-E
Calliopius leviusculus (Kr.)
*Apherusa gracilis Holmes
PLEUSTIDE
Sympleustes glaber (Boeck)
PARAMPHITHOID-E
*E pimeria loricata Sars
BATEIDA
Batea secunda Holmes

PONTOGENEIID
Pontogeneia inermis (Kr.)
GAM MARIDE
*+Eucrangonyx gracilis (Smith)
+Crangonyx tenuis Smith
*Melita parvimana Holmes
M. dentata (Kr.)
M. nitida Smith
Elasmopus levis (Smith)
Gammarus locusta (Linn.)
G. annulatus Smith
G. marinus Leach
Carinogammarus mucronatus
(Say)
tDikerogammarus fasciatus
(Say)
DEXAMINIDZE
Dexamine thea Boeck

ORCHESTIID
Orchestia agilis Smith
O. palustris Smith
Talorchestia longicornis (Say)
T. megalophthalma (Bate)
Hyale prevostu (Milne-Ed.)

AORIDZE
Microdeutopus gryllotalpa
Costa

*M. damnoniensis (Bate)

Lembos smithi (Holmes)

PHOTIDE
Photis reinhardi Kr.
Podoceropsis nitida (Stim.)
Leptocheirus pinguis (Stim.)
AMPHITHOIDE
Amphithoe rubricata (Mont.)
A. longimana Smith
Grubia compta (Smith)
JASSIDE
Jassa marmorata Holmes
Ischyrocerus anguipes Kr.

COROPHIID-®
Cerapus tubularis Say

*Ericthonius rubricornis (Stim.)

E. brasiliensis (Dana)

Unciola trrorata Say

Siphonecetes smithianus
Rathbun

Corophium cylindricum (Say)

CHELURIDE

*Chelura terebrans Phil.

CAPRELLIDEA
Aeginella longicornis (Kr.)
Caprella geometrica Say

*C, @quilibra Say

C. linearts (Linn.)

HYPERIIDEA.

Head not fused with first thoracic segment; maxillipeds with-
out palp; coxal plates small or wanting; head generally large

No. 26.] ARTHROSTRACA OF CONNECTICUT. 45

and tumid, with large, compound eyes which cover nearly the

whole side of the head; gills on three or four thoracic segments ;

last two abdominal segments fused, uropods usually with laminate

rami, forming a tail fan. Hepato-pancreatic tubes two or none,

rectal gland wanting; heart with two pairs of ostia, rarely three.
Exclusively pelagic in habitat.

Hyperia Latreille.

Antenne in female very small, subequal.

Mandibles with molar tubercle large, palp of moderate size
with the second and third joints subequal in length. First max-
ill with palp not greatly expanded, inner corner produced tc a
tooth-like projection. Maxillipeds with outer plates obtuscly
pointed, inner margin with small tufts of sete.

Gnathopods scarcely chelate; .carpus produced ventrally,
especially in second pair. Pereiopods comparatively short, robust,
and subequal in length. Uropods broad, with foliaceous rami.
Telson large.

Hyperia galba (Montagu).

1813. Cancer Gammarus galba, Montagu, Trans. Linn. Soc.
London,rvol) 11; p.:4, pli2;.fie. 2.

1890. Hyperia galba, G. O. Sars. Crust. Norway, vol. 1,
pay, pls: 2.and. 3, fig. 1.

Head much deeper than long, with reniform eyes covering
whole lateral aspect ; back strongly arched.

Antenne in female very short, subequal. Mandibles with
long, slender three-jointed palp.

Gnathopods small, scarcely chelate, and with only a few
bristles; first pair with carpus having postero-distal angle ex-
panded somewhat to form an acutely triangular lobe which is
provided with a few sete; propodus oblong, slender, with poste-
rior margin finely serrate; dactyl small. Second pair with carpus
greatly produced at posterior apex, forming a slender triangular
lobe which reaches beyond the middle of the propodus; the
latter quite similar to that of the first gnathopod.

Pereiopods subequal in length, robust, and almost devoid of
sete ; coxal plates small; basal joint of each stout.

Last two abdominal segments fused; uropods broad, with
foliaceous rami; second pair not extending as far as the first; ter-

46 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull

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Fic. 4: Hyperia galba.

minal pair with peduncle broader distally than proximally, with
rather broad, sharply pointed, subequal rami.

Telson slightly longer than broad, triangular.

In the male the antenne exceed half the length of the body.

Length 15 mm. According to Bovallius, Arctic specimens
may attain a length of 20 mm.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 47

The species is abundant and widely distributed. It has been
reported from the Arctic Ocean, Norway, Great Britain, France,
Greenland, Nova Scotia, Grand Manan; Eastport, Maine; Salem,
Woods Hole, Massachusetts; off Fishers Island, New Haven,
Noank, Connecticut.

It is found commonly in the jelly fish, Aurelia. Sars states
that several individuals, males, females, and young, may occur
in each medusa.

Miss Rathbun in her List of the Crustacea of New England
notes that Hyperia medusarum has been found off New Haven
and at Noank. In the material at my disposal I was unable to
identify H. medusarum, and am inclined to believe that H. galba
is the only Hyperid occurring in the waters of the State.

GAMMARIDEA.

Head not fused with first segment of thorax, and not tumid;
maxillipeds with palp of 2 to 4 joints; coxal plates always well
developed ; eyes simple or compound, of various sizes, but never
covering whole side of head; gills present on 5 or 6 segments;
first uropod always biramus. Hepato-pancreatic tubes generally
4, occasionally 2; rectal glands 2 or 1, sometimes rudimentary ;
heart with 3 pairs of ostia, rarely one pair.

Typical Amphipoda.

KEY TO THE GENERA OF GAMMARIDEA.

A. Mandible not denticulated, palp 3-jointed; antenna 1 with stout
peduncle and accessory flagellum well developed; coxal
plates deep; gnathopod 2 elongated and slender, ischium
elongated, propodus small and densely setose, dactyl rudi-
mentary (Lysianassidz).

SREMNGLS OMeMeIRUIe wrteyra ere trern coc rieceteseco neue cee heroine Lysianopsis p. 51
BB. Telson cleft.
C. Postero-lateral angle of third abdominal segment not
greatly produced.
D. Mandibular palp inserted directly above molar tubercle
Tmetonyx p. 54
DD. Mandibular palp inserted behind molar tubercle .....
CC. Postero-lateral angle of third abdominal segment
Orchomenella p. 58
produced, with a deep sinus above.
D. Peduncular joints of antenna 1 produced distally
Hippomedon.

48 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

DD. Peduncular joints of antenna I not produced distally
Anonyx.
AA. Without this combination of characters.
B. Eyes simple, usually 4 (Ampeliscide).
C. Uropod 3 extending much beyond the others, telson ob-

lone! andi-deeply cleft 18. <2. 35) cS-eeeer ee Ampelisca p. 61
CC. Uropod 3 not extending much beyond the others, telson
short) and*not.deeply- cleft 2. ss.,nbeee ee Byblis p. 67
BB. Eyes usually present, never more than one pair and never
simple.
Cy Pereiopods swithout dacs aeemeeee eee Haustorius p. 70

CC. Pereiopods with dactyls.
D. Rostrum produced into a hood over the antenne; pereio-
pod 4 much longer than last pair (Phoxocephalidz).

EE; Eyes swatitings i. s4 4ih ie Geter eee here bee Harpinia.
BE AB yes still Oar soci cin earners Phoxocephalus p. 73
EE EE vesolanee: sear comeeedce note ricts Paraphoxus p. 75

DD. Rostrum not as above.
E. Coxal plate 4 greatly enlarged to form large lateral

shield.
iB. Uropody3 bisaimousee atc oan cee Stegocephalus p. 60
FF. Uropod 3 uniramous.
G. Mandibular ‘palp) small? >s-jointed| Ga-emee eee Metopa.
GG. Mandibular palp wanting ......... Stenothoe p. 78

EE. Coxal plate 4 not greatly enlarged.

F, Body depressed, rostrum large, broad not acute; no
accessory flagellum; mandibular palp large;
enathopod 1 simple; gnathopod 2 weakly sub-
Chelate. eset ac a ela ersepn he sere tk ee aee ee Lafystius.

FF. Without this combination of characters.

G. Last pereiopod the longest, dactyl styliform; eyes
nearly contiguous above ...... Monoculodes p. 83

GG. Dactyl of last pereiopod not styliform.
Et. Gnathopoden aiudimentamyacn ans Batea p. 89
HH. Gnathopod rt not rudimentary.
I. Pereiopods 1 and 2 without spinning glands,
J. Antenna I with calceoli.
K. Last joint of peduncle of antenna I pro-
duced to form a triangular process..
Calliopius p. 86
KK. Last joint of peduncle of antenna I not
Solphodiucediareian tne Pontogeneia p. QI
JJ. Antenna 1 without -calceoli.
K. Mandible with palp; uropods 2 and 3 not
enormously developed.
L. Thoracic segments strongly tubercu-
lated) ee5) Saati et cio eine eee Epimeria.

No. 26.] ARTHROSTRACA OF CONNECTICUT.

LL. Thoracic segments not strongly tuber-
culated.

M. Postero-lateral margin ‘of, third ab-

dominal segment serrated ........

49

Apherusa.

MM. Postero-lateral margin produced to
a single tooth, above which is a
‘ small sinus.
N. Uropod 3 biramous Sympleustes p.
NN. Uropod 3 uniramous ..Unciola p.
MMM. Postero-lateral margin otherwise;
accessory flagellum present; uro-
pod 3 flattened and usually project-
ing beyond the others; gnathopods
subchelate, gnathopod 2 larger
than 1 and larger in male than fe-
male; telson small and flattened
(Gammaride).
N. Uropod 3 uniramous Crangonyx p.
NN. Uropod 3 biramous.
O. Telson slightly emarginate. .....
Eucrangonyx p.
OO. Telson deeply cleft.
P. Inner ramus of uropod 3 rudi-
mentary, scale-like Melita p.
PP. Inner ramus of uropod 3 often
smaller than outer, but not
rudimentary.
Q. Last 3 abdominal segments
with fascicles of spines.
R. Body with median carina..

Carinogammarus p.

RR. Abdominal segments 4
and 5 raised dorsally to
spiniferous tubercles ...

Dikerogammarus p.

RRR. Body without carina or

tubercles Gammarus p.

QQ. Last 3 abdominal segments

without fascicles of spines;

uropod 3 with compara-

tively broad, short rami ..

Elasmopus p.

KK. Mandible with palp; uropods 2 and 3
enormously developed ..... Chelura p.

KKK. Mandible without palp; no accessory
flagellum; uropods 2 and 3 normal.

84
165

95

93

98

113

105

107

102

174

50

CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

L. Uropod 3 biramous; antenna I long ....
Dexamine p.
LL. Uropod 3 uniramous; antenna I much
shorter than antenna 2 (Orchestiidz).
M. Maxilliped with 3-jointed palp; an-
tenna I shorter than peduncle of
antenna 2.
N. Gnathopod 1 of female subchelate
Orchestia p.
NN. Gnathopod 1 of female simple ..
Talorchestia p.
MM. Maxilliped with 4-jointed palp; an-
tenna 1 longer than peduncle of
antenna 2.
N. Gnathopod 2 in male with carpus
masked by merus ..... Hyale p.
NN. Gnathopod 2 in male with carpus
produced between merus and pro-
podus.
O. Telson undivided ....Hyalella p.
OO. Telson cleft ....Allorchestes p.
II. Pereiopods 1 and 2 glandular; coxal plate 4
not excavate behind.
J. Gnathopod 1 much larger than gnathopod 2
(Aoride).
K. Gnathopod 1 in male with carpus pro-
longed to form a strong thumb-like

PEOCESS hisiae ce eee Microdeutopus p.
KK. Gnathopod 1 in male with carpus not so
produced setacuc re eee Lembos p.

JJ. Gnathopod 1 never much larger than gnath-
opod 2, usually smaller.
K. Uropod 3 biramous.
L. Rami of uropod 3 not uncinate

(Photidz).
M. Rami of uropod 3 very unequal in
SIZ Ch Tee cae eet Meee eee Photis p.

MM. Rami of uropods 3 not very un-
equal in size.

N. Antenna 1 with third joint of pe-

duncle shorter than first .......

Leptocheirus p.

NN. Antenna 1 with third joint of pe-

duncle longer than first ........

Podoceropsis p.

LL. Rami of uropod 3 very short, outer

one uncinate.

ts

122

126

128
131

133

136

139

143

141

No. 26.] ARTHROSTRACA OF CONNECTICUT. 51

M. Lower lip with principal lobes
notched (Amphithoide).

N. Without accessory flagellum; uro-
pod 1 with peduncle not produced
below. .cami 3...% +. Amphithoe p. 147

NN. Accessory flagellum present; uro-
pod 1 with peduncle produced
to spiniform process below rami

Grubia p. I5I
MM. Lower lip with principal lobes en-
tire in front (Jassidz).

N. Gnathopod 2 in male with propodus
having a thumb-like process; in
female much larger than gnath-
OPOd Teer. tore le ce ee Jassa p. 154

NN. Gnathopod 2 in male without
thumb-like process; in female not
much larger than gnathopod 1

Ischyrocerus p. 156
KK. Uropod 3 uniramous (Corophiidz).
Pe Wropod axuiira mois cea Cerapus p. 159
LL. Uropod 2 biramous.
M. Gnathopod 2 in male complexly sub-

Clielapermcrsee «sie eie.: Ericthonius p. 161
MM. Gnathopod 2 in male simply sub-
chelate.

N. Mandibular palp uniarticulate .....
Siphonecetes p. 168

NN. Mandibular palp biarticulate ....
Corophium p. 170

LYSIANASSIDZ:.

Eyes usually large, compound.

First antenne not longer than second pair; first joint of
peduncle tumid; accessory flagellum always present.

Mandibles with cutting edge not denticulate; molar tubercle
seldom very robust; palp triarticulate.

Second gnathopods slender, with ischium elongate, carpus
and propedus spinulose, and dactyl minute.

Terminal uropods biramous. ~

Lysianopsis Holmes.
Antenne short and differing little in the two sexes.
Mandibles edentate, furnished with 3-jointed palp and a smali
‘molar process nearer the cutting edge than is the base of the

52 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

palp; first maxille with narrow inner plate furnished with two
apical sete, palp 2-jointed; maxillipeds with inner plate narrow
and extending beyond middle of outer one, outer plate oval, inner
margin devoid of spines; palp narrow.

First gnathopods stout, simple; second gnathopods slender,
ischium elongated, propodus short and setose, with dactyl very
small, near middle of distal margin of propodus.

Postero-lateral angle of third abdominal segment rounded.

Uropods biramous. Telson entire.

Lysianopsis alba Holmes.

1903. Lysianopsis alba, Holmes, Amer. Naturalist, vol. 37,
p. 276.

1905. Lysianopsis alba, Holmes, Bull. Bur. Fish., vol. 24,
Pp. 475, pl. 5, fig. I.

Interantennal lobes prominent and rounded; eyes large, oval.

First antenne short with basal joint of peduncle stout, and
longer than the next two; principal flagellum a little longer than
peduncle; accessory flagellum one-half the length of the principal
one. Second antennz about as long as first, with flagellum as
long as peduncle.

First gnathopods simple, stout, basal joint broad; carpus
somewhat inflated; propodus tapering distally, dactyl moderately
stout. Second gnathopods very long and slender; merus densely
setose on convex posterior margin; carpus long, with both front
and hind margins convex, densely setose anteriorly; propodus
subcordate, small, densely setose; dactyl very small.

Posterior group of pereiopods increasing in length rapidly
posteriorly, the last pair quite long and slender and having poste-
rior margin of basal segment serrated; two preceding pairs
with basal segments similarly serrated.

Fourth abdominal segment slightly indented dorsally.

First uropods extending further back than second, which
extend further back than the third; rami of first pair nearly as
long as peduncle, styliform; peduncle of last uropods very stout,
longer than the rami and produced into a triangular projection
at distal end of upper margin.

Telson oblong, entire, rounded distally.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 53

ie

era aa

ees
ie =

Color white or yellowish. Often the yellow or orange gonads
may be seen through the integument.
Length 6 mm.

hic. 5. Lysianopsis alba.

54 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Holmes found the species in the mud at Woods Hole, Massa-
chusetts, and off Nobska at the same place. In the Biological
Survey of Woods Hole this species was dredged in 4 to 13
fathoms on bottoms of sand and gravel. It has also been collected
within Connecticut at Noank in mud and grass; off Stonington;
Long Island Sound.

According to Holmes, the species has the habit of lying very
quiet for a long time with its body strongly flexed and of starting
quickly when disturbed and swimming vigorously for a time and
then coming to a sudden stop with its body flexed as before.

Tmetonyx Stebbing.

Epistome more or less projecting and rounded in front.

Antennz with small calceoli in male.

Mandibles with large molar tubercle, obliquely truncate, with
palp attached dorsal to it, second and third joints of palp sub-
equal. First maxillz with two sete on inner plate; outer plate
broad and obliquely truncate; palp with several spine teeth
apically. Second maxillz with inner plate smaller than outer.
Maxillipeds with outer plates large, oblong oval, reaching as far
as second joint of palp which is not very robust.

First gnathopods slender with propodus oblong and palm very
oblique and rather indistinctly defined. Second gnathopods with
ischium greatly elongated; propodus not at all produced beneath
the minute dactyl. First pereiopods elongate, with large basal
joint,

Third uropods projecting beyond the second; rami minutely
denticulate. Telson oblong, deeply cleft.

The name Hoplonyx by which this genus was formerly
known, was preoccupied as a coleopteran genus.

Tmetonyx cicada (Fabricius).

1891. Hoplonyx cicada, G. O. Sars, Crust. Norway, vol. 1,
p: 925 pl. 32) hig: 2.

1906. Tmetonyx cicada, Stebbing, Das Tierreich, Lief, 21,
Pp. 74. |

Head with interantennal lobes only slightly projecting and
rounded.

Eyes not very large, narrow above, broader below.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 55

First antenne as long as head and first two thoracic segments
together, with thick peduncle, the first joint of which is more than
twice as long as the other two combined; flagellum not quite twice
as long as peduncle; accessory flagellum not quite half as long as
flagellum, made up of seven joints. Second antenne half again
as long as first pair; flagellum made-up of about 28 segments.

First gnathopods with propodus as long as carpus with palm
somewhat arcuate’and finely serrated but not defined below by
prehensile angle. Second gnathopods with propodus half as long
as carpus. Two posterior pairs of pereiopods rather elongated,
with basal joint of moderate size.

Anterior coxal plates more than twice as deep as respective
segments and increasing in height posteriorly; fourth pair pro-
duced below the posterior emargination to a narrow lobe, obtuse
at the tip; fifth pair nearly as deep as broad.

Third abdominal segment with postero-lateral angles drawn
out to very short point.

Last pair of uropods with inner ramus scarcely longer than
basal joint of outer. Telson nearly twice as long as broad, slightly
tapering distally and with two pairs of dorsal denticles, and
very narrow cleft extending almost to the base.

Length 15 mm.

Distribution ; Arctic regions; Norway; British Isles; Iceland;
Greenland; Labrador; Woods Hole, Martha’s Vineyard, Massa-
chusetts.

The species ranges in depth to over 600 fathoms.

Tmetonyx quadratus sp. nov.

Head produced to a small rostrum; interantennal lobes
rounded. Body stout.

Eyes oval; deeply pigmented in alcoholic specimens.

First antennz scarcely as long as head and first two thoracic
segments together, with short peduncle about two-thirds as long
as flagellum; first joint of peduncle large, more than half as
broad as long; second and third joints short; accessory flagellum
half as long as principal one and made up of six joints. Second
antenne over a third as long as body; last two joints of peduncle
subequal in length; flagellum with calceoli and made up of about
twenty segments.

56 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

First four coxal plates more than twice as deep as correspond-
ing segments; first pair with front margin considerably shorter
than hind one; first and second coxal plates with a minute
triangular prolongation at the postero-ventral angle; fourth plate
deeply excavated behind to accommodate the fifth which is
deeper than wide and bilobed.

First gnathopods of male with merus with hind margin pro-
longed distally and having several long spines and fine cilia;
carpus triangular, as long as propodus and broader, with a
dense patch of short cilia on the short hind margin; propodus
subrectangular, with oblique palm which is slightly uneven and
finely serrated, prehensile angle prominent and armed with two
stout spines. Second gnathopods with short merus having a patch
of dense cilia on the convex hind margin; carpus greatly
elongated, broadening somewhat distally, with a patch of short
cilia situated near proximal end of hind margin and one near
distal end of front margin, which also bears several long sete;
propodus only slightly longer than wide, densely setose and pro-
duced slightly to form a very weak chela with rudimentary dactyl.

Third, fourth, and fifth pereiopods with basal joints expanded
and serrated on posterior margins.

Third abdominal segment with postero-lateral angle not pro-
duced, but forming nearly a right angle.

First and second uropods with styliform rami; the first pair
extending beyond the second pair; third pair extending slightly
beyond the first; rami foliaceous, inner one extending scarcely
farther than basal joint of outer, inner margins of rami with sete,
outer margins with short strong spines.

Telson flat, twice as long as wide, cleft nearly to the base,
each apex provided with a small spine.

Length 13 mm.

The species is represented by four specimens collected by
Professor Verrill off Stonington, Connecticut, in April, 1873,
in sand at a depth of “ 4-6 f.”

It is distinguished from T. cicada by the shape of the eyes
which in the latter species are narrow above and dilated below;
by the presence of a definite prehensile angle on the propodus of
the first gnathopod; by the form of the postero-lateral angle of

57

ARTHROSTRACA OF CONNECTICUT.

26. |

‘snyvaponb xkuojamy ‘9 “ol

58 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

the third abdominal segment; and by the greater length of the
last peduncular joint of the first antenna.

Orchomenella G. O. Sars.

Coxal plates large.

First antennz with moderately developed accessory flagellum ;
second antennz in females slightly longer than first, not greatly
elongated in male.

Mandibles with slender palp, attached behind the small molar
tubercle; first maxilla with outer plate very obliquely truncated
at tip; maxillipeds normal.

First gnathopods strong, subcheliform; second gnathopods
with short propodus which is dilated distally and densely setose,
apex slightly produced beneath the minute dactyl.

Pereiopods short, basal joint of last three pairs laminar.

Terminal uropods in female scarcely reaching beyond the
preceding pair, rami partly denticulated at the edges; in male
only the outer ramus provided with sete.

Telson reaching beyond peduncle of terminal uropods, oblong,
triangular, deeply incised, lobes not widely separated.

Orchomenella pinguis (Boeck).

1890. Orchomenella pinguis, G. O. Sars, Crust. Norway,
VOLAT, p.67,.pl> 24, fig. 2:

1905. Tryphosa pinguis, Holmes, Bull. U. S. Bur. Fish., vol.
24, P. 473-

Eyes rather large, elongated, not pigmented in alcoholic speci-
mens. Interantennal lobes of head produced and narrowly
rounded.

First antennz short, with stout peduncle having second and
third joints very short; first joint of principal flagellum elongated
and densely setose, succeeding joints short; accessory flagellum
moderately developed, four-jointed, extending beyond the third
joint of principal flagellum. Second antennze much longer than
first, especially in the male in which it scarcely equals one-half
the body length; peduncle short; flagellum in male very slender.

First gnathopods with deep coxal plate slightly narrower
ventrally ; basal joint slender; carpus with narrow posterior lobe;
-propodus rectangular with palm nearly transverse and slightly

No. 26.] ARTHROSTRACA OF CONNECTICUT. 59

Fic. 7. Orchomenella pinguis.

convex. Second gnathopods with propodus oblong, densely
setose, postero-distal angle produced; dactyl,; very small; carpus
considerably larger than propodus with posterior margin strongly
convex.

Posterior pereiopods short with basal joints broadly suboval
and shorter than rest of limb. Coxal plates large, those of first
four appendages being more than twice as deep as their cor-
responding segments; the fifth is much deeper than wide, with

60 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

posterior part of lower margin produced into a rounded lobe.
First three abdominal segments with postero-lateral angles
evenly rounded and with margin above angle minutely crenulated ;
fourth abdominal segment with a rather deep dorsal depression
near the anterior end.

Terminal uropods with styliform rami; inner ramus more
slender than outer and extending only as far as basal segment of
the latter. Telson tapering distally and cleft to beyond the middle.

Color whitish.

Length, 5 mm.

Distribution: Arctic regions ; Norway; Greenland; Labrador ;
Woods Hole; off Martha’s Vineyard; Long Island Sound.

This species has been referred recently to the genus Tryphosa
but it differs from the latter particularly in the position of the
mandibular palp which is behind the molar tubercle; in the carpus
of the first gnathopod which is shorter than the propodus (in
Tryphosa the two joints are more nearly of the same length)
and in the propodus of the second gnathopod which is not pro-
duced beneath the dactyl in Tryphosa.

STEGOCEPHALIDAS

Head short. Fourth coxal plates large.

First antennz with accessory flagellum uni- or biarticulate.
Second antenne seldom much longer than first.

Lower lip without inner lobes. Mandibles without molar
tubercle or palp. First maxille with inner plate with numerous
setee. Second maxillze with inner plate very broad and setose,
outer narrow.

Gnathopods not subchelate. Third pereiopods with basal joint
not expanded.

Terminal uropods biramous. Telson small. >

Stegocephalus inflatus Kroyer.

1891. Stegocephalus inflatus, G. O. Sars, Crust. Norway,
vol. 1, p. 198, pl. 60.

Body tumid and smooth. Rostrum prominent, deflexed, and
with a deep sinus below.

Eyes wanting. First antenne with accessory flagellum having
second joint minute.

Mandibles with palp wanting.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 61

First five coxal plates greatly developed and presenting an
evenly rounded contour below. First gnathopods stouter. than
second ; propodus of both narrow. Last pereiopods with infero-
posterior angle of basal joint produced and acute.

Terminal uropods with lanceolate rami which are nearly twice
as long as peduncle. Telson cleft beyond middle, strongly taper-
ing in distal half.

This species is extensively distributed in the Arctic and north
Atlantic Oceans; Grand Manan; Eastport, Maine; South of
Block Island; near Woods Hole, Massachusetts.

AMPELISCIDA.

Head truncate in front, no rostrum.

Byes simple, usually two pairs.

First antennz without accessory flagellum. Second antennz
attached far behind first pair.

Gnathopods imperfectly subchelate, carpus never shorter than
propodus; second pair longer and more slender than first. First
and second pereiopods with very large merus; dactyl slender and
elongate.

Telson generally very deeply cleft.

Ampelisca Kroyer.

First coxal plate scarcely deeper than second, often concealing
the base of second antennz; fourth obliquely truncate below
posterior angle.

Eyes four, or none, simple.

Mandibular palp with second joint flattened and third joint
linear and rather short. First maxille with outer plate trans-
versely truncated and palp having the terminal joint gradually
expanded distally and armed at the apex with several strong
teeth. Maxillipeds with inner plate oval; penultimate joint of
palp nearly club-shaped and scarcely half as long as the second
joint.

Third and fourth pereiopods with very broad basal joint,
carpus bearing a simple row of spines within hind margin; fifth
pereiopods with basal joint greatly expanded and with ventral
margin fringed with plumose sete; propodus foliaceous; dactyl
lanceolate.

62 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Terminal uropods reaching considerably beyond the others;
rami foliaceous, inner one broader than outer one.
Telson oblong, cleft nearly to base.

Ampelisca macrocephala Lilljeborg.

Fic. 8. Ampelisca macrocephala.

1852. <Ampelisca macrocephala, Lilljeborg, Ofvers. af Kgl.
Vet. Akad. Forhandl., p. 7.

1895. Ampelisca macrocephala, G. O. Sars, Crust. Norway,
Vola; -p.vt72,. pl: 60, ie: rT. .

Head about as long as first three thoracic segments, frontal
part produced and obliquely truncated at the tip.

Eyes simple, two pairs, surrounded by bright red pigment in
life; lower pair of eyes at antero-lateral angle of head.

First antennz in female extending as far as peduncle of sec-
ond pair; flagellum, twice as long as peduncle; in the male con-
siderably longer. Second antenne of female scarcely more than

No. 26.] ARTHROSTRACA OF CONNECTICUT. 63

half the length of body, last segment of peduncle shorter than
preceding one.

First pair of coxal plates widened distally and extending as
far forward as the eyes. Propodus of first gnathopods oblong
and not as wide as carpus, but about as long. Second gnathopods
with very elongated carpus and propodus only half as long as
carpus.

First and second pereiopods with dost considerably longer
than the two preceding joints combined. Last pereiopod with
basal joint broadly rounded below; ischium broader than long;
merus produced into a pointed setose lobe at lower posterior
angle; carpus heart-shaped with three long ciliated setz on pos-
terior angle, which is more produced than the corresponding an-
terior one; propodus oblong, tapering distally, and scarcely
longer than the two preceding joints combined; dactyl about as
long as propodus.

Third abdominal segment having the postero-lateral angle
with a long, acute, slightly upturned projection, above which is
a rounded sinus followed by a rounded lobe.

Terminal uropods with rami broadly lanceolate and about
twice as long as peduncle; second pair with outer ramus some-
what shorter than inner and armed near the tip with a very
long slender spine. Telson oblong oval, about twice as long as
broad, deeply cleft, with four pairs of dorsal denticles and a
single pair of apical spines.

Color whitish.

Length 15 mm.

Distribution; Arctic regions; Greenland; Labrador; Iceland;
British Isles; Casco Bay, Maine; Cape Ann, Woods Hole,
Massachusetts ; Newport, Rhode Island; North of Fishers Island
in 3%-5 fathoms, Noank and New Haven (S. I. Smith),
Connecticut.

The species seems to be confined almost entirely to muddy
bottoms and is abundant in eel-grass.

Ampelisca limicola (Stimp.), recorded by Verrill (Am. Jour.
‘ Sci., ser. 3, vol. 10, p. 38) from the Noank region, is probably
this species, according to an unpublished drawing of A. limicola
by. S22: Smith;

The individuals of this bee. agree with Holmes’s descrip-
tion and differ from Sars’s figures of Norwegian specimens in

64 CONNECTICUT GEOL. AND NAT. HIST. SURVEY.

{ Bull.
that the first pair of coxal plates project a little farther forward,
the dactyl of the last pereiopod is as long as, or a little longer

than, the propodus; and the dactyls of the first two pereiopods
are a little larger.

Ampelisca spinipes Boeck.

=-- =
so [
a
7

—_ =: ee

Fic. 9. Ampelisca spinipes.

1860.

Ampelisca spinipes, Boeck, Férhand. ved. de Skand
Naturf., vol. 8, p. 653.
1891.

Ampelisca spinipes, G. O. Sars, Crust. Norway, vol. 1,
ps 273, pl..60, mg. 72:

No. 26.] ARTHROSTRACA OF CONNECTICUT. 65

First antenne of female slightly longer than peduncle of
second pair and nearly half as long as body; first joint of peduncle
rather stout ; flagellum about three times as long as peduncle, with
fascicles of slender sete ; flagellum in male extremely slender and
provided with very fine hairs. Second antenne in female half
again as long as the first pair, last two joints of peduncle not
greatly elongated, subequal; in the male exceeding the length of
body and with last joint of peduncle rather longer than preceding
one.

First gnathopods with propodus nearly as long as carpus and
somewhat bulging on proximal portion of posterior margin.
Second gnathopods very slender, the narrow carpus nearly twice
as long as propodus.

First and second pereiopods with dactyls about as long as pre-
ceding two joints combined. Last pair with ischium nearly twice
as long as wide, much longer than the nearly square merus;
carpus subrectangular, elongated; propodus longer than carpus
or dactyl.

Postero-lateral angle of third abdominal segment not pro-
duced, forming nearly a right angle; fourth abdominal segment
of male with a prominent dorsal carina which ends abruptly
posteriorly ; following segment deeply indented above; the cor-
responding features in the female are much less pronounced.

Second uropods with no long terminal spine on outer ramus.
Terminal uropods thickly setose in the male but nearly devoid of
setze in female..

Telson very narrow and nearly smooth, excepting for three
small marginal spinules near tip of each terminal lobe.

Color whitish, with a rose-colored or light-purplish spot in
first coxal plate, and a few other spots of same color on other
parts of the body.

Length 14 mm.

Distribution: Norway, North Sea, France; Woods Hole,
Massachusetts; Newport, Rhode Island; off New London, Con-
necticut; Fisher’s Island Sound, off Stonington, Noank, off Sea
Flower Key, off Saybrook (Smith), Savin Rock (near New
Haven), Long Island Sound.

The species is quite abundant, being very common on sandy,
gravelly, and muddy bottoms, and among eel-grass (Smith).

It occurs at depths up to 10-12 fathoms.
5

66 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

It is probably the same as A. typica (Bate) which is recorded
by Verrill (Am. Jour. Sci. ser. 3, vol. 10, p. 38) from the Noank
region. He did not describe it but a comparison of specimens
so labelled in Peabody Museum as well as of an unpublished
figure by S. I. Smith confirm this identity.

Ampelisca compressa Holmes.

1903. Ampelisca compressa, Holmes, Amer. Naturalist, vol.
37; P. 273-

1905. Ampelisca compressa, Holmes, Bull. U. S. Bur. Fish.,
vol, 24, p: 480, pl.6, fie, 1.

This species I have never met with either at Woods Hole or
along the Connecticut coast although Holmes states that it is the
most common species of Ampelisca in the Woods Hole region.

I quote Holmes’ description verbatim:

“ Body strongly compressed and generally strongly flexed;
head markedly shorter than first three segments of thorax; first
antenne shorter than peduncle of second pair; third joint of
peduncle a little shorter than first; flagellum only a little longer
than peduncle, second antennz slender, over half length of body
in female, and much longer than body in adult male; peduncle in
male over a third length of body; last joint a little shorter than
preceding one; first four coxal plates higher than their segments,
the first considerably expanded below; first and second peraeo-
pods with dactyl slender and longer than two preceding joints.
Posterior pereeopods with basal joint widely expanded; ischium
as broad as long; merus with a posterior lobe extending to middle
of carpus. Postero-lateral angle of third abdominal segment
broadly rounded; fourth abdominal segment in both sexes with
a prominent dorsal crest which increases in height posteriorly
and carries a pair of short-setz on its posterior margin; terminal
uropods similar in two sexes, furnished with only a few short
spinules and sete; outer ramus of nearly same width throughout
its length; telson about two-thirds as wide as long, lobes rather
obtuse distally, but with inner angles subacute.”

Length 6 mm.,

Distribution: Vineyard Sound; Newport, Rhode Island; off
Block Island; Long Island Sound.

It is found, according to Miss Rathbun, from the surface to
depths of 47 fathoms.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 67

Ampelisca agassizi (Judd).

1896. Byblis agassizi, Judd, Proc. U. S. Nat. Mus., vol. 18,
p. 599, figs. 9-11.

This species is somewhat intermediate between Am~pelisca and
Bybhs, but agrees with the former genus in that the telson is
much longer than broad and cleft nearly to the base, in the
form of the last pereiopods, and in the fact that the last pair
of uropods project much beyond the other ones and have no
serrations on the opposing margins of the rami.

It is distinguished from other species of Ampelisca found on
the New England coast by the fact that the body is not unusually
compressed, the postero-lateral angle of the third abdominal
segment is not produced, the telson is broad and cleft nearly to
the base, and the merus of the last pair of pereiopods is pro-
duced distally nearly to the middle of the carpus behind.

The species was obtained by Mr. Judd by skimming the sur-
face of Narragansett Bay at Newport, Rhode Island, in the
summer of 1893.

Byblis Boeck.

Corneal lens, when present, two pairs.

Antenne slender. Mandibles rather strong; second joint of
palp not expanded, third joint short. Maxille as in Ampelisca.
Maxillipeds with inner plate narrow and truncated at tip.

Gnathopods very slender, especially the posterior ones.

Last pair of pereiopods with basal joint produced posteriorly
to a very large lobe fringed on anterior and ventral margins with
short ciliated sete; propodus not at all expanded, sublinear;
dactyl extremely narrow and tipped by two unequal bristles.

Last pair of uropods scarcely reaching beyond the preceding
pairs, rami narrowly lanceolate, not setose in female, their
opposite edges being more or less distinctly serrated.

Telson short and broad and only slightly incised posteriorly.

Byblis serrata Smith,

1874. Byblis serrata, Smith, Rep. Com, Fish. for 1871-2, p.
561.

Eyes two pairs, simple, situated very far forward on the
truncated head.

68 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

First antenne in male less than one-half as long as body,
extending beyond peduncle of second antenne; first joint of

7
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i

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Tic. 10, Byblis serrata.

peduncle stout and shorter than second joint which is cylindrical,
last joint less than one-half as long as second; lower margins of

No. 26.] ARTHROSTRACA OF CONNECTICUT. 69

second and third joints with many fascicles of sete; flagellum
long and slender.

Coxal plate of first gnathopod projecting considerably ante-
riorly so that the mouth parts are hidden, lower margin serrate
and armed with set; second joint very long and slender; carpus
longer than the propodus which is rectangular and three times as
long as broad, posterior margin with sete and stout spines; dactyl
stout.

Second gnathopods with rhomboidal coxal plate which is
provided with setz ventrally; carpus much longer than in first
pair; propodus similar to that of first pair.

Fourth coxal plate incised posteriorly, about as long as high.
First and second pereiopods with spinning glands; merus very
long and setose; carpus and propodus short; dactyl slender and
longer than propodus. Last pair of pereiopods with basal joint
expanded distally, posterior margin nearly straight, ventral
margin evenly curved and reaching as far as distal end of carpus
and provided with a fringe of sete; carpus as long as ischium
and merus together, a little less than twice as long as broad,
spinous on anterior and distal margins; propodus nearly as long
as carpus, nearly four times as long as broad, with two
transverse rows of spines and with distal margin having a long
spine on each side of base of the long, slender dactyl.

Third abdominal segment with postero-lateral angles rounded.

Uropods biramous. First pair with equal rami, styliform and
slightly longer than peduncle which bears a number of short
spines dorsally. Second pair not extending as far as first; outer
ramus shorter than inner. Third pair with equal rami which are
longer than the peduncle and extend as far as first pair, inner
margin of inner ramus provided with long sete, outer margin
serrate, outer ramus with inner margin serrate. Telson slightly
longer than broad, lateral margins evenly curved and converging
rapidly to the evenly rounded extremity, cleft for more than half
its length.

In alcoholic specimens the coxal plates, bases of posterior
pereiopods and sides of the abdomen are provided with large,
irregular flecks of dark pigment.

Length 10-12 mm,

70 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Distribution: Woods Hole, Massachusetts; Newport, Rhode
Island ; Fishers Island, New York; Fishers Island Sound; Noank,
Connecticut.

The species has been found from the surface to 11 fathoms
- in Fishers Island Sound. Professor Smith found the species off
Vineyard Sound and Buzzards Bay to a depth of 20-29 fathoms
on bottoms of fine compact mud and sand.

Judd in Proceedings of the U. S. National Museum, vol. 18,
p. 596, 1896, describes the sexual differences of the species.

HAUSTORIIDA&

Coxal plates of moderate size, usually fringed with sete;
fifth coxal plate bilobed.

First antennz shorter than second, with accessory flagellum.

Mandibles with cutting edge not dentate; secondary incisive
plate and molar tubercle large, palp triarticulate.

Gnathopods seldom powerful, weakly subchelate or chelate.

Pereiopods often adapted for burrowing.

Uropods all biramous. Telson flattened, more or less deeply
Gleit.

Haustorius Statius Miller.

First antennz with well developed accessory flagellum.
Second antennz longer than the first; fourth joint of peduncle
laminarly expanded.

Mandibles with rather large palp. First maxilla with densely
ciliated flap-like expansion outside outer plate; palp well devel-
oped. Maxillipeds with inner and outer plates of nearly equal
size; palp with second joint produced at end interiorly to rounded
lobe, third joint bent to a right angle, fourth joint wanting.

Gnathopods comparatively feeble; propodus of first simple;
that of second pair forming a minute chela. Two anterior perei-
opods with carpus having a rounded, lamellar expansion poste-
riorly. Three posterior periopods very wide. Dactyls wanting
in all pereiopods.

Uropods, first pair with both rami coarsely spinous at trun-
cated tips; second pair with rami setose; last pair with rami
slender and linear, the outer biarticulate and longer than inner.

Telson broad, slightly incised in middle.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 71

: Haustorius arenarius (Slabber).
1818. Lepidactylus dityscus, Say, Jour. Acad. Nat. Sci.
Phila. vol; 1; -p. 380.
1906. Haustorius arenarius, Stebbing, Das Tierreich, Lief.
Ate 125. |

AAS
eo 4

: ji ,

fi
p

S

Fic. 11. Haustorius arenarius.

Head as long as first two segments of body, with short, tri-
angular rostrum; eyes small and nearly round, inconspicuous in
alcoholic specimens.

72 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

First antenne as long as head and first two thoracic segments
together ; peduncle with second and third joints expanded distally
and together longer than the first joint, provided with numerous
plumose sete; accessory flagellum over half as long as principal
one which is scarcely as long as peduncle. Second antennz longer
than first and having the last two joints of the peduncle greatly
dilated and with inferior margin strongly convex and provided
with abundant plumose setz, penultimate joint much longer than
last one and with a rounded distal lobe extending one-third as far
as last segment; flagellum shorter than peduncle and made up
of about ten segments.

Body somewhat depressed.

First four coxal plates increasing successively in size poste-
riorly, over twice as deep as corresponding body segments. First
three tapering below to rather obtuse points; fourth one rounded
below and much larger than others.

Gnathopods weak; first pair with carpus longer than propo-
dus and dactyl, and with posterior margin evenly convex and
provided with long sete; propodus simple; dactyl short. Second
gnathopods very slightly longer than first, propodus very slender
and chelate; dactyl very small.

Dactyls wanting in all the pereiopods. First and second
pereiopods small and subequal with carpus broader than long,
due to a rounded lobe on posterior margin; propodus dilated
distally ; third pereiopod considerably larger than second and
with greatly expanded basal joint and merus and carpus dilated
transversely; fourth pereiopod largest, with basal, meral, and
carpal joints greatly expanded; fifth pereiopod with basal joint
broader than long and with anterior and posterior margins very
strongly convex, merus with a very long lobe projecting
posteriorly which is armed with sharp spines and plumose sete.

Uropods biramous; second pair smallest; terminal pair not
projecting quite as far as first pair, outer ramus _biarticulate.
Telson short and broad, strikingly bilobed, with sete on distal
and outer margins.

The color according to Bate is pale grayish yellow, resembling
somewhat closely the sand in which it lives.

Length 18 mm.

Distribution: Georgia to Cape Cod. Specimens have been
found at New Haven, Connecticut.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 73

This species occurs on sandy shores, where the animals burrow
near low-water mark with great dexterity, being by far the most
rapid burrowers among the Amphipoda. It is also occasionally
found under stones in sandy places, and is dredged in shallow
water.

It can not easily be confused with any other Amphipod be-
cause of its broadly expanded pereiopods devoid of dactyls.

PHOXOCEPHALIDZ.

Rostrum projecting like a hood over bases of antenne.

Coxal plates rather large.

First antennze with accessory flagellum well developed.

Mandibles with cutting edges distinctly developed, molar
tubercle not large; palp large. First maxille with inner plate
small, palp uni- or biarticulate. Maxillipeds: with plates small
and palp large.

First and second gnathopods generally similar in form, sub-
chelate, large. Fourth pereiopod the longest.

Terminal uropods often varying sexually, outer ramus the
longer, biarticulate.

Telson deeply cleft.

Phoxocephalus Stebbing.

Head with acute hood.

First antennz shorter than second which in the male are very
elongated and slender and bear calceoli on the flagellum.

Mandibles with molar tubercle distinctly developed; palp well
developed. First maxillaee with very small uniarticulate palp.
Second maxillz with the plates nearly equal. Maxillipeds with
outer plate scarcely larger than inner; palp with fourth joint
slender.

Gnathopods unequal, the posterior ones being the larger.
Third pereiopods with basal joint laminarly expanded; last pair
with basal joint very large.

Last uropods in female with inner ramus naked and much
shorter than outer ; those in male much larger with both rami well
developed, lanceolate, furnished marginally with ciliated setz.

Lobes of telson narrow.

74 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Phoxocephalus holbdlli (Kroyer).
1842. Phoxus holbélli Kroyer, Naturh. Tidsskr., vol. 4, p.

T50.
1888. Phoxocephalus holbélli, Stebbing. Rep. Voy. Chal-

lenger, vol. 29;"p> 1717.
1891. Phoxocephalus holbélli, G. O. Sars. Crust. Norway,

vol, 1, p> 144, pl.c40:

rate

yo PS
fr S fo az, g a:

Mx

Fic. 12. Phoxocephalus holbolli.

Body smooth, Head produced forward to form an acute,
triangular hood over antennze; eyes poorly developed, incon-
spicuous.

First antennz with first joint of peduncle thick and longer
than second and third together, and with a triangular process
distally; principal flagellum 6-jointed; accessory flagellum 3-
jointed. Second antennz with penultimate joint of peduncle
enlarged distally and considerably longer than last joint and
armed with many long sete and several spines; flagellum 6-

No. 26.] ARTHROSTRACA OF CONNECTICUT. qs

jointed in female, with first joint as long as second, third, and
fourth together.

Coxal plates of first and second gnathopods rectangular,
higher than wide, with several long setz on posterior portion of
lower margin.

Gnathopods of same form except the carpus of first is longer
than that of second; propodus of second slightly longer than that
of first, oblong in form but slightly broader distally, palm oblique
and convex, separated from hind margin by prominent triangular
process and spine; carpus with three sete on hind margin.

Third pereiopod with basal joint broader proximally than
distally and with front margin slightly concave; fourth pereiopod
about one-half as long as body, basal joint provided with
numerous sete on anterior margin; fifth pereiopod with basal
joint as long as rest of limb and as broad as long, posterior
margin strongly convex and finely serrate.

Postero-lateral angle of third abdominal segment narrowly
rounded.

Uropods biramous with rami narrowly lanceolate. In
female, terminal uropod with inner ramus scarcely half as long
as outer, second joint of outer less than half the length of first;
in male, rami nearly equal, plumose, outer ramus with three spines
on outer margin. Telson much longer than broad, cleft to the
base, narrowed distally, with two spines -and a seta on each
rounded apex.

Color light buff or orange.

Length 5 mm.

Distribution: Arctic regions ; North Atlantic coast of Europe;
Greenland ; Labrador; Grand Manan; Bay of Fundy; Casco Bay;
Vineyard Sound in deep water (Smith) ; Newport, Rhode Island;
Long Island Sound. Low water to 45 fathoms.

Paraphoxus G. O. Sars.

Hoed evenly vaulted, not carinated.

Antenne in female nearly equal-sized; second ones in male
not very elongated, flagellum very slender, provided with calceoli.

Mandibles with very poorly developed molar tubercle; palp
extremely slender. First maxillz with palp larger than in Phoxo-
cephalus but sti-wntarticulate. Second maxille with inner lobe

(GAUSS Heels

76 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

smaller than outer. Maxillipeds with inner plates obtusely
rounded at tip; third joint of palp oval; fourth joint very slender
and curved.

Gnathopods exactly alike in size and form, propodus oval,
constricted at base. Pereiopods as in Phoxocephalus.

Last pair of uropods dissimilar in the two sexes, compara-
tively simple in the female with inner ramus much shorter than
outer; in male much larger, with both rami well developed and
fringed with ciliated sete.

Telson with narrow lobes.

Paraphoxus spinosus Holmes.

1903. Paraphoxus spinosus, Holmes, Amer. Naturalist, vol.
37; P- 276.

1905. Paraphoxus spinosus, Holmes, Bull. U. S. Bur. Fish.,
vol. 24, p. 477.

Head produced into triangular rostrum which projects be-
yond the basal joint of the first antennze. Eyes large in male,
much smaller in female.

First antennze very short, only slightly longer than peduncle
of second antennz of male; peduncle stout ; flagellum shorter than
peduncle; accessory flagellum well developed. Second antennze
in male with stout peduncle and very long slender flagellum con-
siderably more than one-half as long as body, made up of
elongated segments which bear calceoli. In female the flagellum
of the second antennz is scarcely longer than peduncle.

First four coxal plates gradually increasing in depth poste-
riorly ; fourth pair much larger than the others, with hind margin
incised; first to third pairs rhomboidal, with a few fine sete on
postero-ventral angle.

Gnathopods similar in size and shape; second joint rather
slender; carpus longer than propodus, stouter at distal than at
proximal end; propodus broader distally than proximally; palm
nearly transverse and marked off from posterior margin by a
triangular process which bears a spine;.dactyl very slender.

First and second pereiopods subequal; merus stout and longer
than carpus which is tapering and armed distally with a very long
curved spine; propodus slightly longer than carpus, with three or
four short spines on hind margin; dactyl very small and spine-like.

‘No. 26.] ARTHROSTRACA OF CONNECTICUT. 77

Fic. 13. Paraphoxus spinosus.

78 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Third pereiopod stout with basal joint well expanded and sub-
rectangular in form; fourth, fifth, and sixth joints very stout;
and subequal in length, dactyl very small. Fourth pereiopods
also stout; basal joint broader than in preceding appendage and
more rounded; propodus much longer than carpus. Fifth pereio-
pod somewhat smaller than preceding two; second joint broadly
expanded posteriorly and with hind margin dentate.

Posterior margin of lateral expansion of third abdominal
segment furnished with a few sete.

First uropod with peduncle long and slender and provided
near distal end with a few spines; rami styliform and somewhat
shorter than peduncle. Second uropod shorter and stouter than
first with peduncle and rami provided with numerous spines.
Third uropod extending beyond others; peduncle short; rami
in male subequal and laminar, provided on margins with
numerous plumose sete, outer ramus with short distal joint. In
female outer ramus much larger than inner and biarticulate with-
out plumose sete.

Telson subrectangular, incised nearly to base; lobes evenly
rounded and provided toward lateral aspect with two very short
spines.

Length 4.5 mm.

Distribution: Newport, Rhode Island (S. D. Judd); off
Stonington, Noank, Noank Harbor (surface), Connecticut ; Long
Island Sound.

STENOTHOID-.

Similar to the Metopide except as follows:
Mandibles without molar tubercle or palp. First maxilla with
biarticulate palp. Maxillipeds with inner plates small; outer
plates obsolete.

Stenothoe Dana.

Coxal plates of moderate size except fourth which is greatly
produced posteriorly and covers to a great extent the succeeding
pairs.

Antenne elongated and as a rule subequal in length.

Mandibles without palp and with molar tubercle obsolete.
First maxilla with palp large and biarticulate. Maxillipeds with

No. 26.] ARTHROSTRACA OF CONNECTICUT. 79

inner plates small and narrow; palp elongated, with unguiform
fourth joint finely ciliated inside.

First gnathepods as a rule much smaller than second and
subcheliform. Third pereiopods with basal joint linear, merus of
last two pairs laminarly expanded.

Last pair of uropods elongated.

Telson well defined, squamous, entire.

Stenothoe cypris Holmes.

Fic. 14. Stenothoe cypris.

1903. Stencthoe cypris, Holmes, Amer. Naturalist, vol. 37,
p.°273:

1905. Stenothoe cypris, Holmes, Bull. Bur. Fish., vol. 24,
p. 484.

Eyes round and deeply pigmented in alcoholic specimens.

Antennz subequal in length and about one-third the length of
body ; first pair with first joint of peduncle very stout and nearly
as long as next two joints; flagellum about as long as peduncle
and made up of about six joints, the first of which is as long as
the last joint of peduncle. Second antenne with long slender
peduncle having last two joints subequal and third joint of

80 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

peduncle not much longer than broad; flagellum of about six
joints.

First gnathopods simple; basal joint long and slender with
short seta on outer margin; merus widened and rounded distally
with distal half of posterior margin provided with short sete
and two pectinate spines; carpus shorter than propodus and of
uniform diameter; propodus slightly tapering. Second gnatho-
pods larger than first, with well developed oval coxal plate; basal
joint slightly longer than that of first pair; merus broader at
distal than at proximal end and with hind margin much longer
than anterior one; carpus broader than long and with a narrow
rounded lobe bearing a few pectinate spines projecting posteriorly
farther than preceding joint; propodus oblong, widest behind the
palm which is quite oblique and bears a stout spine near hind
margin.

First pereiopods with well developed oval coxal plate as large
as that of second gnathopod. Coxal plate of next pereiopod
enormous, equalling the first six segments in length, oval in out-
line, much broader than deep. Coxal plates of succeeding pereio-
pods small and rounded.

First uropods with peduncle nearly twice as long as the sub-
equal, lanceolate rami; second pair not reaching as far as the
first pair and with peduncle slightly longer than the subequal
lanceolate rami. Third pair with peduncle equal to the single
ramus which is composed of two unequal segments. Last two
abdominal segments fused.

Telson entire, acute.

Holmes states in his description that the coxal plate of the
first gnathopod is well developed and that of the first pereiopod
is small. This is evidently an error for in specimens from Long
Island Sound the condition is reversed, the coxal plate of the
first pereiopod being well developed and that of the first gnatho-
pod very small.

I quote Holmes’ description of the color and habits of the
species :

“ Body pellucid ; first segment more or less rose-colored above,
a row of rose-colored or sometimes brownish spots or bars along
middle of back; eyes rose-colored; joints of peduncle of antennz
yellowish at tip; a dark bar across tip of abdomen and base of

No. 26.] ARTHROSTRACA OF CONNECTICUT. 81

uropods; gills with a tinge of rosecolor. . . . . This species
swims in an irregular, jerky manner and after swimming but a
short distance suddenly stops, flexes the body, and drops to the
bottom. Its motions in the water resemble those of the ostracod,
Cypris.”

Length 2 mm.

Distribution: Woods Hole, Massachusetts; Long Island
Sound.

Holmes obtained this species in material secured from piles
at Woods Hole in September and also among masses of Pennaria.

Stenothoe minuta Holmes.

Per Gr

Fic. 15. Stenothoe minuta.

1903. Stenothoe minuta, Holmes, Amer. Naturalist, vol. 37,
p.' 278.

1905. Stenothoe minuta, Holmes, Bull. Bur. Fish., vol. 24,
p. 485.

Eyes round.

Antennz subequal in length and a little over one-half as long
as body; first joint of first pair very much thicker than second
and nearly as long as second and third; flagellum slender, about
twelve-jointed. Second antennz with last two joints of peduncle
of nearly equal length; flagellum with somewhat fewer joints

than first pair.
6

82 CONNECTICUT GEOLi AND NAT. HIST. SURVEY. [| Bull.

First gnathopods with coxal plates small; basal joint with a
few slender spines on anterior margin; merus rounded below,
where it is furnished with four spine-like setee and several much
shorter ones; carpus produced posteriorly into a rounded lobe
which has about three large spine-like sete at its distal end;
propodus nearly twice as long as wide, palm very oblique and
minutely pectinated like inner margin of dactyl. Second gnatho-
pods larger than first; coxal plate large; basal joint more or less
sigmoid; merus produced below into stiff sete and three large
spines at the tip; propodus widest across distal end of palm which
is oblique, only slightly curved, not pectinated, and armed at
distal end with two or three pairs of spines. Pereiopods of sub-
equal length; posterior pairs with basal joints considerably ex-
panded, and merus rather broad and produced downward at
postero-inferior angle; dactyls of all pereiopods large. Fourth
coxal plate not unusually large for the genus, scarcely ovate.

First uropods long and slender with lanceolate rami subequal
and nearly equal to peduncle; outer ramus of second uropods
markedly shorter than inner; the single ramus of terminal uro-
pods about as long as peduncle, with proximal joint a little shorter
than conical terminal one and armed with a spine at distal end of
upper margin; peduncle with a spine above near middle and a
spine at distal end. Telson flattened, oblong, pointed, entire, with
three small spines near lateral margins.

Color pellucid, marked with scattered reddish-brown spots.

Length about 2.5 mm.

Distribution: Woods Hole, Long Island Sound. Holmes
found it among seaweed and on piles.

GEDICERIDA.

Eyes, when present, usually contiguous above.

First antennz with accessory flagellum absent or rudimentary.

Mandibles with palp usually large.

First gnathopods subchelate. Second pair subchelate or
rarely chelate. Last pereiopods very large with dactyl styliform.

Uropods commonly extending back to the same distance.
Telson small, entire.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 83

Monoculodes edwardsi Holmes.

1903. Monoculodes edwardsi, Holmes, Amer. Naturalist, vol.

37, P- 275.
1905. Monoculodes edwardsi, Holmes, Bull. U.S. Bur. Fish.,
vol. 24, p. 487. :

Eyes nearly contiguous above and situated in front of base
of rostrum, which is triangular and curved downwards.

First antennz without accessory flagellum, shorter than second
pair. |

Mandibles with second joint of palp bent inwards and about
as long as third joint. First maxillz with inner plate suboval and
bearing two sete at tip; first joint of palp longer than broad,
second joint spatulate. Maxillipeds with inner plate small and
oblong, not reaching the distal end of first joint of palp; outer
plates reaching only a little beyond the middle of the broad second
joint of palp.

First gnathopods with carpal lobe long and distally setose;
propodus oval, with palm evenly convex. Second gnathopods
with a slender carpal process which scarcely extends beyond the
middle of the palm. Coxal plates unusually small. Anterior
pereiopods with carpus prolonged into a long lobe which extends
behind the short propodus. Last pair of pereiopods much longer
than the preceding, with very long, styliform dactyl.

Rami of last pair of uropods a little longer than peduncle.
Telson oblong and distally rounded.

Length 9 mm.

Distribution: Wcods Hole, Massachusetts and Newport,
Rhode Island.

PLEUSTIDA::

Rostrum more or less prominent. Fifth to seventh coxal
plates small.

First antennz without accessory flagellum, longer than second
pair; flagellum in both pairs made up of many segments.

Mandible with third joint of palp falciform. First maxillze
with inner plate small. Maxillipeds with inner and outer plates
small and not strongly armed, and with palp long.

First and second gnathopods often alike, subchelate. Third
to fifth pereiopods with basal joint expanded.

84 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Third uropods with rami longer than peduncle, slender, lanceo-
late, spinulose; outer ramus shorter than inner. Telson small,
entire or (very rarely) notched, boat-shaped.

Sympleustes Stebbing.

Rostrum small, coxal plates moderate.

Mandibles with molar tubercle cylindrical and with large palp,
the last joint of which -is falciform. First maxillz with well
developed palp slightly dilated distally ; inner plate with two sete
apically. Maxitlipeds with broad inner plates ; outer plates small ;
palp with fourth joint small.

Second gnathopods larger than first and more pronouncedly
subchelate.

Terminal uropods elongated with inner ramus longer than
outer. Telson small, entire.

Sympleustes glaber (Boeck).

1861. Amphithopsis glaber Boeck, Forh. Skand. Naturfor.,
vol. 8, p. 662.

1899. Sympleustes glaber, Stebbing, Ann. and Mag. Nat.
EList,, set 7, VOl. Ae. p.,206,

Head projecting to form a small rostrum, lateral angles rather
prominent and acute. Back evenly rounded. Eyes large and
irregularly circular.

First antennz longer than second, about two-thirds as long as
body ; first joint of peduncle large, cylindrical, bearing a tooth-like
process on ventral distal angle; second and third segments shorter
than first; flagellum long and multiarticulate. Second antennz
with last two joints of peduncle equal in length; flagellum long
and slender.

First four coxal plates deeper than wide and increasing in
height posteriorly, first three with small tooth-like projection at
postero-inferior angle; fourth rather deeply incised posteriorly.
Fifth, sixth, and seventh coxal plates low.

First and second gnathopods not very unlike in form or size,
first slightly smaller than second. Fourth joint with small tri-
angular process at postero-distal angle and with distal margin
provided with several long setz; carpus triangular, shorter than
propodus and about as broad, posterior angle rounded and with

No. 26.] ARTHROSTRACA OF CONNECTICUT. 85

many slender sete; propodus irregularly oval, palm convex and
considerably longer than posterior margin, provided with several
spines and numerous sete; dactyl long and slender.

Fic. 16. Sympleustes glaber.

Pereiopods subequal in length; third, fourth, and fifth with
second joint expanded with posterior margin well rounded and
serrate. Fourth joint of last 3 pereiopods with postero-distal
angle acute; sixth joints longer than the corresponding ones of
first and second pereiopods.

Third abdominal segment with postero-lateral angle in form
of a small slightly upturned tooth with a concavity above it.

First uropods slender, with peduncle considerably longer than
rami which are acuminate, dorsal margin of peduncle and rami
with short spines; second uropods of same form as first but
peduncle considerably shorter, outer ramus shorter than inner;
third uropods not extending as far posteriorly as second, outer
ramus much shorter than inner.

86 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Telson small, oval, twice as long as broad and rounded distally.

Length 6 mm.

Distribution: Arctic Ocean, Greenland, Iceland, Norway,
Fishers Island Sound, Long Island Sound, off Stonington,
Connecticut.

CALLIOPIMDAE:

Coxal plates not large.

First antennz with peduncle usually short and accessory
flagellum uniarticulate or wanting.

Mouth parts varying slightly from the normal.

First and second gnathopods usually feeble, subchelate.

Marsupial plates of female large and broad.

Terminal uropods with inner ramus longer than outer. Telson
entire, sometimes a little notched or emarginate.

Calliopius Lilljeborg.

Antenne stout, subequal in length, both having flagella divided
into numerous short and sharply defined articulations carrying
large calceoli ventrally, last peduncular joint of first antennz
produced to a triangular process which also bears calceoli; acces-
sory flagellum wanting.

Mandibles with comparatively large palp in which the terminal
joint is as long as the second.

Gnathopods strong, with short carpus produced posteriorly
to a setiferous lobe; propodus large with palm occupying nearly
its entire length and imperfectly defined.

Last uropods scarcely reaching beyond the others, peduncle
comparatively short, rami subequal and lanceolate.

Telson not incised at tip, tongue-like.

Calliopius leviusculus (Krdyer).

1838. Amphithoe leviuscula, Kroyer, Kongel. Danske
Videns-Kabernes Selskabs Skrifter, Copenhagen, vol. 7, p. 281,
plese fee 13: :

1871. Calliopius leviusculus, Boeck, Forh. Videnskabs-
Selskabst, Christiania, 1870, p. 197.

1906. Calliopius leviusculus, Stebbing, Das Tierreich, Lief.
21a ps, 200:

Eyes large, reniform.

87

SSSA Ns

Fic. 17. Calliopius leviusculus.

First antennz shorter than second and with first joint of
peduncle considerably thicker and a little longer than second;
third joint with a conspicuous triangular process projecting below
flagellum and bearing about eight calceoli on lower margin; flagel-
lum longer than peduncle, with joints produced at antero-inferior
angle and each provided with a pair of calceoli and severai
olfactory setz on lower side. Second antennz with last two
joints of peduncle subequal in length, the fourth joint extending
as far as the second joint of first antenne; flagellum subequal
to peduncle, joints not produced below, furnished with calceoli.

88 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

First four coxal plates deeper than broad aud about as deep
as their respective segments and increasing successively in depth.

First and second gnathopods of similar form and nearly equal
size, the second being a trifle the larger, and with the lobe on the
posterior side of carpus longer and narrower than in first; propo-
dus ovate, palm very oblique with a row of stout spines on outer
side which begins a little beyond the middle of the palm.

First two pairs of pereiopods with merus strongly produced
downward at anterior angle; last three pereiopods with merus
strongly produced downward at posterior angle, that of last pair
being more dilated than in the preceding ones.

First three abdominal segments more or less produced at
posterior end to form a keel, especially developed in older speci-
mens, and second, third, fourth, and sometimes also first de-
pressed in front. Postero-lateral angles of second and third seg-
ments with a small tooth.

First uropods with outer ramus markedly shorter than inner
which is a little shorter than the peduncle, both margins of
peduncle and rami armed with numerous short spines; second
uropods with peduncle relatively broader than that of first and
somewhat shorter than inner ramus, outer ramus much shorter
than inner; terminal uropods extending beyond the others, rami
flattened, lanceolate, subequal, much longer than peduncle with
both margins of each furnished with numerous spines and
plumose sete.

Telson oblong, slightly tapering and rounded at tip.

Length 13 mm.

Distribution: Greenland, Labrador, Halifax, Arctic regions,
Norway, British Isles, Narragansett Bay (Judd), Vineyard
Sound (Smith), Woods Hole, Gloucester, Long Island Sound.

The species is largely pelagic and is often taken in large
numbers on the surface at Woods Hole, especially in the winter.

BATEIDA.

Head strongly rostrate. First coxal plate rudimentary.
First antennee without accessory flagellum.

Mandibles with palp.

First gnathopods degraded, without propodus or dactyl.
Telson cleft.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 89

Batea Fr. Miiller.

Head with strong rostrum.

First antennz without accessory flagellum and a little shorter
than second.

Mandibles with palp. Maxillipeds with outer plates fully
reaching apex of second joint of palp, fringed with spine teeth
on inner margin.

First gnathopods with coxal plate rudimentary, ending with
a feeble linear basal joint which is longer in female than male.
Second gnathopods subchelate. Third to fifth pereiopods with
basal joint expanded.

Second uropods shorter than first or third; last uropods with

short peduncle and flattened rami. Telson short and deeply cleft. |

ae lee
Batea secunda Holmes. = D _ catt ONY

Fic. 18. Batea secunda.

1903. Batea secunda, Holmes, Amer. Naturalist, vol. 37, p.
284.

1905. Batea secunda, Holmes, Bull. Bur. Fish. for 1904, vol.
24, Pp. 499.

Head with a rather prominent narrow rostrum. Eyes very
large.

go CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

First antennz nearly as long as second; first joint of peduncle

much stouter and a little longer than second; third joint small,
less than half the length of second; flagellum consisting of about
eighteen elongated segments. Second antennz nearly half as
long as body with last two joints of peduncle of nearly equal
length. .
First gnathopods consisting simply of a rudiment of the coxal |
plate and basal joint, of which the former is very small and the
latter is curved and rounded distally where it is provided with a
few curved sete. Second gnathopods slender; carpus with a
large, triangular posterior lobe; propodus with oblique palm, only
slightly curved and minutely denticulated ; dactyl with four spini-
form projections on inner margin behind tip. Second, third, and
fourth coxal plates about as deep as their respective segments ;
that of second pereiopod broader than deep and deeply excavated
at upper posterior maggin; the three posterior pereiopods in-
creasing successively in length; basal joints broad; last pair con-
siderably longer than preceding.

Posterior margin of third abdominal segment with several
upturned teeth above the rounded postero-lateral angle.

First two pairs of uropods with styliform rami, and outer
ramus considerably shorter than inner; second pair not extending
nearly so far backward as first or third; third uropods with rami
flattened, lanceolate, over twice the length of the peduncle,
margins of each with short spines and sete. Telson deeply cleft.

Length 5 mm.

Distribution: Woods Hole, Massachusetts; Long Island -
Sound. Dredged at depths of 6 to 25 fathoms.

According to Holmes: “The body and coxal plates in the
living specimens were marked with blue or purplish pigment
spots. . . . . Sometimes the blue or purplish color of these
spots 1s replaced by a reddish brown, and in some specimens
neither kind of spots occurs.”

PONTOGENEIIDZ.

Body compressed. Rostrum not prominent.

First antenne with peduncle not elongate, accessory flagellum
usually wanting, never more than uniarticulate.

Mouth parts normal.

No. 26.] , ARTHROSTRACA OF CONNECTICUT. gI

*

Gnathopods with propodus not powerful, subchelate.

Third uropods with rami subequal, of moderate size. Telson
deeply cleft.

Pontogeneia Boeck.

Body slender, with none of the segments produced dorsally.

Antenne slender and elongated, with the first pair a little
shorter than the second and without an accessory flagellum; in
the males, peduncles with calceolli.

Gnathopods subequal, feeble; carpus considerably elongated
and scarcely expanded below; propodus narrow, with palm
shorter than hind margin.

Terminal uropods with peduncle short, rami subequal and
lanceolate. Telson unarmed and deeply cleft.

Pontogeneia inermis (Kroyer).

1838. Amphithoe inermis, Kroyer, Danske Vid.-Selsk.
Afhandl: vol. 7, p. 275, pl. 3, fig. 11.

1893. Pontogeneia inermis, G. O. Sars, Crust. Norway, vol.
Ep. 451, pl. 150:

Body slender and compressed, with back evenly rounded
throughout. Rostrum small, interantennal lobes short and
obtusely rounded. First three coxal plates rounded quadrangular
in form with ventral edge minutely crenulated; fourth pair con-
siderably larger than preceding and produced posteriorly below
the emargination to an angular projection.

Eyes oblong, reniform.

Antenne in female without calceoli. First pair nearly half as
long as body; first joint of peduncle scarcely longer than second
but somewhat thicker; last joint half the length of second, and
produced below distally to small triangular process; flagellum ~
twice as long as peduncle and composed of numerous short articu-
lations. Second antenne a little longer than the first pair, with
the last two joints of peduncle subequal ; flagellum fully twice as
long as peduncle. In male, antennze much more fully developed
than in female and with last two peduncular joints provided
with large calceoli; flagellum very slender and elongated.

First gnathopods with propodus shorter than carpus and but
very slightly widened distally, palm oblique, scarcely half as long
as posterior margin from which it is defined by a very slight angle

g2 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Fic. 19. Pontogeneia inermis.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 93

armed with a transverse row of small spines. Second gnathopods
scarcely longer than the first and of similar structure, except that
propodus is more expanded distally. Pereiopods moderately
slender and edged with fascicles of small spines; posterior three
pairs successively increasing in length and with basal joint
rounded, oval in form with posterior margin smooth.

Last pair of uropods projecting beyond the others; rami more
than twice as long as peduncle and edged with small spinules and
sete. Telson reaching well beyond the peduncle of last uropods,
oblong oval in form, cleft extending beyond the middle and
gradually widening toward apex, terminal lobes obtusely pointed.
The species is nearly colorless, with scattered purplish spots and
the antennz with a few transverse purplish bars.

Length 11 mm.

Distribution: Arctic Ocean, Norway, Halifax, Bay of Fundy
to Greenland (Smith), Grand Manan, Vineyard Sound, Long
Island Sound, Fishers Island Sound.

The species is often associated with Calliopius leviusculus
according to Holmes and is found commonly in tide-pools as well
as at the surface.

GAMMARID.

Body slender.

Antenne generally slender; accessory flagellum often greatly
developed, but sometimes wanting.

Mouth parts normal.

Gnathopods generally powerful; sometimes more powerful
in male than female. Pereiopods more or less slender, sometimes
basal joint of pereiopods three to five only slightly expanded.

Terminal uropods with rami foliaceous and projecting beyond
the others. Telson either entire or cleft to the base.

Eucrangonyx Stebbing.

Body compressed, not carinate.

First to fourth coxal plates deeper than the following ones.

First antennz longer than the second, and with a small bi-
articulate accessory flagellum.

Maxillipeds with outer plates narrow.

First and second gnathopods subchelate, with propodus not
strikingly broader than carpus. Third to fifth pereiopods with
basal joint moderately expanded.

94 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Terminal uropods not elongate, with small inner ramus.
Telson emarginate.

Eucrangonyx gracilis (Smith).

Fic. 20. Eucrangonyx gracilis.

1871. Crangonyx gracilis, Smith, Amer. Jour. Sci., ser. 3,
vol. 2, p. 453.

1899. Eucrangonyx gracilis, Stebbing, Trans. Linn. Soc.
Lord: ser..2, vol.77, 1p. 423:

1907. Eucrangonyx gracilis, Weckel, Proc. U. S. Nat. Mus.,
vol, 32, p. 322)

Eyes small, elongated.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 95

First antenne slightly more than half as long as the body;
accessory flagellum composed of two joints. Second antenne
half as long as first pair.

First gnathopods in male with propodus having palm slightly
oblique; second gnathopods with propodus increasing in width
distally and more elongate than in first pair, palm oblique, some-
what arcuate. Third, fourth, and fifth pereiopods with basal
joints serrate and with small spines on both margins.

Postero-lateral angles of the first three abdominal segments
produced and terminating in a small tooth.

Third uropods reaching apex of second pair; outer ramus
nearly twice as long as peduncle, inner ramus minute, unarmed.
Telson slightly shorter than peduncle of last uropods, about as
broad as long, cleft about one-third the distance to the base and
with two or three spines on the truncate extremities of the lobes.

Length 7-18 mm.

Distribution: Lakes Superior and Huron; Irvington, Indiana ;
Dalaware, Ohio; Nashville, Tennessee; Providence, Rhode
Island; New Haven, Connecticut.

Crangonyx Bate.

Similar to Eucrangonyx, except that terminal uropods have
a single uniarticulate ramus and the telson may be entire or partly
cleft.

Crangonyx tenuis Smith.

1874. Crangonyx tenuis, Smith, Rept U. S. Fish. Com.,
1872-3, p. 656.

Body elongated and slender; coxal plates lower than their
respective segments; last two abdominal segments fused. First
three abdominal segments longer than last three of thorax; but
fourth, fifth, and sixth together scarcely longer than third.

Eyes invisible in alcoholic specimens; interantennal lobes
small, rounded, projecting.

First antennz less than half as long as body in the male,
with flagellum composed of about twenty-two segments and
twice as long as the peduncle, the first joint of which is slightly
longer than the second and the last joint about one-third as long
as the first; accessory flagellum very small, composed of two
joints, the terminal one of which is very short. Second antenne

[ Bull.

AND NAT. HIST. SURVEY.

GEOL.

UL

CON NECTIC

96

No. 26. ] ARTHROSTRACA OF CONNECTICUT. 07

stout and longer than first pair; last two joints of peduncle sub-
equal ; flagellum about as long as peduncle and composed of about
fifteen segments.

Mandibles large but quite short ; principal cutting edge divided
into three or four teeth; secondary cutting edge likewise denticu-
lated; molar tubercle large and close to cutting edge; palp well
developed, triarticulate with last joint longer than second and
provided with long sete near the slightly pointed tip. Lower
lip broad, with outer plates evenly rounded and with mandibular
processes short and broad; inner plates small. First maxillz
with inner plate broad and rounded, with six plumose spines on
inner margin; outer plate with very oblique distal margin armed
with three strong teeth and inner margin with short sete distally ;
palp strong, made up of two joints of which the distal one is more
than twice as long as the proximal one and armed at its rounded
apex with sete. Second maxille with outer plate curved and
rounded apically, inner plate broader than outer one and tapering
to a rounded apex; outer plate with sete apically; inner plate
with sete at apex and on inner margin. Maxillipeds with very
large palp; inner plate small, rectangular, not reaching as far as
first joint of palp; outer plate with rounded apex, bearing short
setee on inner and apical margins; second joint of palp very long,
with abundant sete on inner margin, third joint about half as
long as first and second together and with sete at apex, fourth
joint about half as long as third, slightly tapering and provided
distally with a spine tooth.

First gnathopods stouter than second pair; basal joint broad,
with sete on posterior margin toward distal end; carpus tri-
angular with sete on short, rounded posterior margin; propodus
longer than basal joint, with very oblique palm extending nearly
to base of joint and armed with a double row of strong, blunt
spine teeth, many of which bear a notch and a cilium near apex;
dactyl very long and curved. Second gnathopods with basal
joints more slender than that of first pair; merus with posterior -
margin very convex and with a fascicle of sete; carpus longer
than in first pair with numerous fascicles of spines on hind
margin; propodus broadly oval, with palm straight and not very
oblique and provided with a double row of spine teeth as in first
pair. First two pairs of pereiopods slender. Third, fourth, and

7

98 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull

fifth pereiopods increasing in length posteriorly ; basal joints not
greatly expanded, with front margins provided with short sete.

Uropods all extending to about the same point; first pair with
subequal rami which are about half as long as peduncle and which
bear spines apically ; second pair with outer ramus about half as
long as inner one, both of which are provided apically with spines ;
last pair small, uniramous; peduncle nearly as broad as long;
ramus rectangular, about twice as long as wide and with apical
spines and sete.

Telson subrectangular, twice as broad as long, tapering
slightly toward the entire and slightly arcuate posterior margin
which is armed with numerous spinules.

The length of the largest males, from which the drawings
in this paper were made, is about 13 mm. The usual length is
only 6-8 mm.

The sexual differences are not great.

According to Smith, in all the females and most of the males
of the smaller size mentioned, the first antennz are longer than
the second and the flagellum of the first is composed of sixteen to
nineteen segments and that of the second pair of only eight to
ten.

The species was originally described from specimens found in
wells in Middletown, Connecticut, but specimens have also been
found at Canaan, and under stones in a small brook near New
Haven.

Melita Leach.

Abdominal segments sometimes produced dorsally to denti-
form projections. Coxal plates moderate, fourth pair largest
and more or less emarginate behind.

First antenne very slender and much longer than second;
accessory flagellum well developed.

Mouth parts normal.

Gnathopods rather unequal, anterior ones being comparatively
small, and the posterior ones being often enormously developed
in the male. Pereiopods rather elongated, the three posterior
pairs increasing successively in length and having the basal joint
expanded.

Last pair of uropods projecting considerably beyond the
others, having the rami very unequal, the inner one being very
minute. Telson small and cleft almost to base.

No. 26 | ARTHROSTRACA OF CONNECTICUT. 99

| Melita nitida Smith.

1873. Melita nitida, Smith, Rep. U. S. Com. Fish. for
1871-2, p. 560.

Body slender and compressed ; eyes small and round.

First antenne two-thirds the length of body, with peduncle
having second joint longer than first and nearly twice the length

Melita nitida.

BIG 22)

100 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

of third; flagellum longer than peduncle; accessory flagellum
three-jointed and not longer than last peduncular joint. Second
antenne shorter than first with last joint of peduncle nearly as
long as preceding; flagellum shorter than peduncle, joints fur-
nished with whorls of long sete.

First four coxal plates deeper than their segments; first three
oblong.

First gnathopods quite similar in the two sexes; carpus
longer and broader than propodus which is oblong, palm about
one-third the length of the nearly transverse distal margin of
the propodus; dactyl short, very much curved and thick at the
base, articulated at middle of distal margin. Second gnathopods
in male with large oval propodus having palm evenly convex
and about as long as posterior margin with which it forms an
almost continuous curve; propodus in female similar to that of
male but smaller. Last three pereiopods with basal joints large,
oblong, armed with short spines in front and serrated behind.
Posterior margins of abdominal segments not dentate or pro-
duced ; fifth segment with several spines on posterior margin on
either side of mid-dorsal line.

Terminal uropods long; inner ramus minute, situated in a
sinus of peduncle; outer ramus similar to that of M. dentata
but armed on either side with more fascicles of longer spines than
in that species. ;

Telson with tip of lobes triangular, acute; with a few spines
around tip and on distal part of inner margin.

Color dark greenish slate.

Length 10 mm.

Distribution: New Jersey to Cape Cod (Smith), Woods
Hole, Massachusetts; New Haven (Smith), Noank Harbor,
Connecticut.

The species is found under stones and among sea weed near
low-water mark.

Melita parvimana Holmes.

1903. Melita parvimana, Holmes, Amer., Naturalist, vol. 37,
Pp. 279.

1905. Melita parvimana, Holmes, Bull. U. S. Bur. Fish.,
vol. 24, p. 506.

This species may be distinguished from other species of Melita
by the fact that the carpus of the first gnathopods is as broad as

/

No. 26.] . ARTHROSTRACA OF CONNECTICUT. IOI

long, and the propodus is short and stout; the second gnathopods
and terminal uropods are also smaller than in most species of
this genus.
Length 12 mm.
The species was described from a single specimen taken at
Newport, Rhode Island.

Melita dentata (Kroyer).

Fic. 23. Melita dentata.

1853. Gammarus purpuratus, Stimpson, Marine Invert.
Grand Manan, Smithson. Contrib. vol. 6, No. 5, p. 55.

1894. Melita dentata (part), G. O. Sars, Crust. Norway, vol.
E513. pl. ton, fie. t

1906. Melita dentata, Stebbing, Das Tierreich, Lief. 21,
p- 427.

Body much compressed; eyes round or oval.

First antennze much longer than second; second joint of
peduncle longer than first and about four times length of third;

102 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

accessory flagellum about five-jointed. Second antenne with
long and slender peduncle having last joint a little shorter than
preceding one; flagellum shorter than peduncle.

First four coxal plates deeper than their respective segments,
the fourth deeper than wide; first three with small tooth at
postero-inferior angle.

First gnathopods of male with carpus and propodus subequal ;
merus with a tuft of very short sete on posterior side; carpus
with a similar tuft at distal end of anterior margin; propodus
suboval, with palm quite evenly convex, very oblique and con-
tinuotts with posterior margin of joint which it equals in length.
Second gnathopods of male with propodus very large and strong
and with oblique palm which has a large triangular tooth near
distal end and is terminated proximally by a large spine tooth.
In female, first gnathopods closely resembling those of male, but
with a relatively longer carpus and smaller propodus. Pereiopods
slender and elongated, with large, oblong basal joints which are
serrated on posterior margins.

Posterior margins of abdominal segments produced into
teeth, the median one of which is the largest, that of the fourth
abdominal segment being the largest of all.

Last pair of uropods elongated, with outer ramus having sides
nearly parallel to near the tip and armed with several fascicles
of spines on each margin; inner ramus minute.

Telson with each lobe terminating‘in an acute point on inner
side of which is a large and a small spine and on outer a spine
or seta.

Color yellowish, with broad transverse bands of dark reddish
brown.

Length 16 mm.

The species is extensively distributed in the Arctic regions,
Norway, Labrador, Buzzards Bay. Several specimens were
dredged, according to Holmes, in Rhode Island waters, off Fishers
Island from 7% to 430 fathoms (Rathbun), Long Island Sound.

Elasmopus Costa.

Body strongly built and smooth. Coxal plates moderate;
fourth pair being largest and distinctly emarginate behind.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 103

First antenne longer than second and provided with a com-
paratively small accessory flagellum.

Mouth parts normal.

Gnathopods subchelate and unequal, the second pair being
the larger and being strongly developed in male. Posterior perei-
opods unusually robust with basal joints very large and laminar.

Last pair of uropods not much elongated, robust, with rami
comparatively broad. Telson laminar and divided by a deep,
narrow cleft into two halves which are spinous at the tip.

Elasmopus levis (Smith).

1874. Mera levis, Smith, Rep. Com. Fish., vol. 1, p. 559.

Eyes nearly round, black. |

First antennz stout, two-thirds as long as body; first and
second joints of peduncle equal in length, third joint two-thirds
as long as second; principal flagellum as long as peduncle and
made up of about 24 rather short segments; accessory flagellum
less than half as long as last joint of peduncle and composed of
two oblong joints and a very short terminal one.

Second antennz slender, scarcely longer than peduncle of
first; fourth and fifth joints of peduncle subequal, third joint
very short, gland cone prominent; flagellum slightly longer than
last joint of peduncle, made up of about eight joints.

Mandibles with three-jointed palp of characteristic form,
last joint having shape of knife blade with row of setz on edge.

First four coxal plates slightly deeper than their respective
segments, fourth about as broad as deep.

First gnathopods of male, with propodus oblong and subequal
to carpus which is provided on posterior margin with numerous
sete, and with palm oblique and evenly convex; basus stout.
Second gnathopods of male very large, carpus very short, with
narrow posterior lobe furnished with dense setz ; propodus oblong
and twice as long as broad, palm short, oblique, smooth, with row
of four or five spines near base of dactyl, which is stout and
closes against an excavation on inner side of propodus.

In the female, first gnathopods much like those of male but
with palm transverse. Second gnathopods much smaller than in
male, of oblong shape resembling the first gnathopods of male;
dactyl slender and closing against palm.

104 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Fic. 24. Elasmopus levis.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 105

Last two pereiopods subequal and stout with merus and ‘carpus
considerably expanded especially in male; basus of third, fourth,
and fifth pereiopods broadly oval.

Terminal uropods biramous, extending beyond the others;
rami short and broad, inner one narrower than outer and slightly
shorter, provided with a small spine near base of inner margin;
outer ramus with three fascicles of spines on outer margin; tips
of both rami truncated and armed with numerous spines.

Telson reaching to base of rami of terminal uropods, nearly
as broad as long, and cleft two-thirds of the way to the base;
lobes cblong and notched at the apex where there may be one or
two spines.

Body olive brown to grayish, marked with numerous small
rounded lighter-colored spots and a series of larger light spots
along mid-dorsal line. In specimens having much gray pigment
the legs are barred with dark bands which in other specimens
may be scarcely visible.

Length 10 mm.

Distribution: New Jersey; Vineyard Sound; Provincetown;
Woods Hole, Massachusetts; Long Island Sound; Noank, off
Stonington, Connecticut.

The species is found under rocks and amid sea weed at low
tide. At Noank it was also found on piles in sponges, etc., in
eel-grass, and on the surface.

Females captured in August at Woods Hole were found with
eggs.

Dikerogammarus Stebbing.

Agreeing in general with Gammarus; but with fourth and
fifth abdominal segments each raised dorsally to a spiniferous
tubercle. First antenne longer than second and with well devel-
oped accessory flagellum.

First and second gnathopods larger in male than in female;
second pair larger than first.

Dikerogammarus fasciatus (Say).
1818. Gammarus fasciatus, Say, Jour, Acad. Nat. Sci., Phila.,

VOUT, Pt.2).p.. 327A:
1874. Gammarus fasciatus, Smith, Rep. U. S. Fish. Com.,

1872-3, p. 653.

106 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

/

Fic. 25. Dikerogammarus fasciatus.

1899. Dikerogammarus fasciatus, Stebbing, Trans. Linn. Soc.
London, ser. 2, vol. 7, p. 428.

Fourth and fifth segments of abdomen slightly raised to a
tubercie dorsally and each armed with three fascicles of spines;
sixth segment also with three fascicles.

First antennz with first and second joints of peduncle nearly
equal in length and twice as long as the third; flagellum twice
as long as peduncle; accessory fiagellum five- or six-jointed.
Second antennz setose, about two-thirds the length of the first;
last two joints of peduncle subequal.

First gnathopods in male with propodus much narrowed
distally and with palm very oblique, with several small prehensile
spines and a stout spine at middle. In the female, the propodus
is less narrowed distally and palm is less oblique. Second gnatho-
pods in male with carpus longer than in first gnathopods; pro-
podus with margins nearly parallel, but widening slightly toward
the palm which is a little oblique and concave and bears a stout
spine near the middle. In the female the carpus is proportionally
longer and as wide as the propodus which is. narrow and
rectangular. |

No. 26.] ARTHROSTRACA OF CONNECTICUT. 107

Terminal uropods extending well beyond the first and second ;
first pair extending beyond second pair; rami of first pair over
half as long as peduncle and armed with spines; outer ramus
of terminal uropods made up of two joints; inner ramus not
quite as long as basal joint of the outer one which 1s very long.
Telson cleft to the base, the lobes being furnished distally with
two or three spines and a few cilia.

Length 10-15 mm.

This species has a wide distribution in the eastern and central
parts of the United States. It has been reported from Eastport,
Maine; Hudson River and Niagara Falls, New York; Lake
Superior; Burlington, Iowa; Lake Geneva, Wisconsin; Washing-
ton, District of Columbia; St. Johns River, Florida; New Haven
and Woodbridge (near New Haven), Connecticut.

It is abundant in fresh-water ponds among weeds and in
brooks under stones.

Gammarus Fabricius.

Abdominal segments provided with fascicles of spines dorsally.
First four pairs of coxal plates moderate, fourth pair the largest,
distinctly emarginated in its upper part.

First antennz generally longer than second, provided with
well developed accessory flagellum. Second antennz rather
strongly built.

Mouth parts normal.

Gnathopods distinctly subchelate and more or less strongly
developed being always much more powerful in male than in
female.. Pereiopods not greatly elongated.

Last pair of uropods projecting beyond the others, with rami
spinous and setous, the outer one generally much the larger, and
having a small terminal joint.

Telson rather small and cleft to the base.

Gammarus locusta (Linnzus).

1894. Gammarus locusta, G. O. Sars, Crust. Norway, vol. 1,
p. 499, pl. 1 and 176, fig. 1.

1906. Gammarus locusta, Stebbing, Das Tierreich, Lief. 21,
p. 476.

108 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Fic. 26. Gammarus locusta.

Body slender and compressed. Eyes elongated; reniform.

First antenne a little longer and more slender than second
and in females generally less than half the length of the body;
peduncle with first joint a little longer than the second, which is
twice the length of the third; accessory flagellum about eight-
jointed and longer than second joint of peduncle. Second antennz

No. 26.] / ARTHROSTRACA OF CONNECTICUT. 109

with stout peduncle which has the last two joints of subequal
length ; flagellum shorter than peduncle.

First gnathopods of male with propodus elongated, much’
longer than carpus, tapering from near the base and with palm,
which is continuous with posterior margin, somewhat uneven
and armed with a spine near the middle and a large spine with a
row of several small ones at distal end. Second gnathopods of
male with propodus much larger than in first, twice as long as
carpus, subquadrate in form, slightly broader toward distal end,
palm oblique and uneven and sharply marked off from posterior
margin, armed with a stout spine near middle and several near
prehensile angle. Gnathopods in female smaller than in male and
more nearly of same size and shape.

Postero-lateral angles of second and third abdominal seg-
ments produced and acute, the margin above the angles generally
furnished with short sete; the three posterior segments with a
median projection bearing a fascicle of spines and a lateral
fascicle on each side.

Terminal uropods with both rami stout, inner one nearly as
long as first joint of outer and armed with about four stout spines.

Telson with a group of two or three spines near base and
three on apical margin, with another spine near the latter close
to the outer margin.

Color olive brown to reddish brown; red, orange, or pink
spots produced by globules may occur at the bases of the pleopods
and first uropods as well as along the intestine.

Length about 25 mm. According to Sars, Arctic specimens
attain a length of 48 mm. A few specimens collected at Savin
Rock, near New Haven, measured 30 mm.

Distribution: Arctic Ocean, Atlantic coast of Europe; Medi-
terranean; also in the Pacific Ocean it extends from Behring
Strait for a considerable distance down the coasts of both North
America and Asia. It is the commonest species along the New
England coast. Within Connecticut it has been reported from
New Haven, Noank, off Stonington, Fishers Island Sound, N.
of Fishers Island (3% to 5 fathoms), Long Island Sound.

In depth it ranges from low-water mark, where it is exceed-
ingly abundant especially under stones, to a depth of over 50
fathoms.

110 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Gammarus annulatus Smith.
1873. Gammarus annulatus, Smith, Rep. U. S. Fish. Com.

for 1871-2, p. 557. ;
Eyes reniform, broader than in G. locusta.

Fic. 27. Gammarus annulatus.

Antennz less than one-third as long as body. First antennz
shorter than second; first joint of peduncle slightly ionger than
second joint, third joint half as long as second; accessory flagel-
lum longer than second joint of peduncle; principal flagellum
slender, composed of about twenty joints. Second antennz with
stout gland cone, and third joint as broad as long, fourth and fifth

No. 26.] ARTHROSTRACA OF CONNECTICUT. ILI

joints of peduncle subequal in length; flagellum stout, not as
long as last two joints of peduncle together.

First four coxal plates deep with lower anterior margins pro-
vided with sete; first coxal plate not produced anteriorly.

First gnathopods smaller than second; carpus triangular,
with posterior margin armed with long sete; propodus oval,
narrower distally, palm oblique and irregular and armed near
middle with stout spine and at prehensile angle with numerous
short spines; dactyl curved. Second gnathopods of same form as
first but the propodus is slightly broader and has a less oblique
palm which bears a stout spine at middle and several short spines
at prehensile angle. Female with propodus of both gnathopods
less stout than in the male and of nearly similar size and shape.

Pereiopods slender; first and second pairs with only a few
spines but with numerous sete which are especially abundant on
the posterior margins of merus and carpus. Third, fourth, and fifth
pairs with basal joints oval and armed with short sete on front
and hind margins.

Second and third abdominal segments with postero-lateral
angles produced slightly to form an acute angle and with lower
margins armed with short spines. Fourth, fifth, and sixth
abdominal segments with median fascicle of spines on posterior
dorsal margin; fifth and sixth segments also with lateral fascicles
of spines.

Uropods biramus; last pair elongated and projecting well
beyond others ; rami narrowly lanceolate with margins abundantly
provided with long plumose spines, outer ramus biarticulate, and
armed on outer.margin also with a number of spines ; inner ramus
extending as far as first joint of outer ramus; peduncle armed
distally with several long spines.

Telson with a variable number of spines on lateral margins
and apically, cleft nearly to base and with lobes widely dehiscent.

Length 15 mm.

The species is found abundantly at times on the surface.
According to Miss Rathbun, it occurs also under stones and in
rock weed above low-water mark and from the surface to depths
of 13 fathoms.

It is found along the New England coast from Eastport,
Maine to New Haven, Connecticut. Within the limits of Con-
necticut the species has also been taken off Fishers Island.

112 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.: 2

Gammarus natator Smith is identical with this species.

G. annulatus is likely to be confused with G. Jocusta but can
be distinguished from the latter by the absence of the lateral
fascicles of spines from the fourth abdominal segment, by the
long sete in place of fascicles of spines on the rami of the last

uropods, and by the different form of the gnathopods.

Gammarus marinus Leach.

reece
A aR
? 5 ! Y \

Lh NOI
P/ hi:

\

LE a

HI

ae \
OS (*

Fic. 28. Gammarus marinus,

1815. Gammarus marinus, Leach, Tr. Linn. Soc. London,

vol. I], p. 359.
"1905. Gammarus marinus, Stebbing, Das Tierreich, Lief. 21,
Pp. 472.
Body slender and compressed. Anterior pairs of coxal plates
not nearly twice as deep as corresponding segments.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 113

Eyes very narrow, reniform; pigment very dark.

First antenne nearly half the length of the body; first joint
of peduncle as long as second and third combined; flagellum
more than twice the length of peduncle, composed of about
thirty-three segments; accessory flagellum not quite half as long
as peduncle and composed of seven joints. Second antenne
considerably shorter than first, and having flagellum somewhat
longer than peduncle.

Gnathopods not very strong, subequal in both sexes, those of
female having propodus oval quadrangular in form with palm
more oblique in first than in second pair; those in male a little
stronger, with propodus more oblong in form. Three posterior
pairs of pereiopods comparatively short and stout with outer
joints armed with fascicles of small spines.

Fourth, fifth, and sixth segments of abdomen with three fas-
cicles of strong spines which are arranged in two rows converg-
ing above, each row arranged in two groups slightly apart.

Last pair of uropods with outer ramus well developed and
coarsely spinous on both edges; inner ramus extremely small,
scarcely one-third as long as outer one, and narrow conical in
form. Telson comparatively small, each lateral half with one
lateral and three apical spines.

Length 15 mm,

Distribution: British Isles; coast of France; Mediterranean ;
Vineyard Sound, Buzzards Bay; Woods Hole, Massachusetts ;
Newport, Rhode Island ; New Haven, Noank Harbor, Connecticut.

The species is found under stones below high-water mark
and is sometimes abundant.

Carinogammarus mucronatus (Say).

1818. Gammarus mucronatus, Say, Jour. Acad. Nat. Sci.
Phi ol t, pio.2,. ps 376.

1905. Carinogammarus mucronatus, Holmes, Bull. Bur.
Fish., vol. 24, p. 503.

Eyes reniform.

First antenne a little longer than second; first joint of pedun-
cle longer than second, third joint three-fifths as long as preced-
ing ; flagellum twice as long as peduncle; accessory flagellum com-
posed of three or four joints and not half as long as peduncle.

8

114 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.
Second antennze with flagellum equal to last two joints of
peduncle, of about ten segments.

First four coxal plates deep; first three oblong ; fourth wide.

First gnathopods in male stout, smaller than second ; carpus
less than half as long as propodus which is narrowly oval, palm
uneven, very oblique and continuous with posterior margin;
propodus of second pair oblong, with the two sides nearly paral-
lel and the palm oblique and concave near the middle.

AY;
SHEL.

&S

Fic. 29. Carinogammarus mucronatus,

Posterior margins of first three abdominal segments pro-
duced backward in the mid-dorsal line into a prominent acute
tooth; last three segments with fascicles of spines.

Third uropods with flattened rami much longer than peduncle ;
outer one biarticulate and larger than inner one and provided on
margins and apex with sete and spines. Telson cleft nearly to
base, and provided with three terminal and a few lateral spines
on each lobe.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 115

Color, olive green with red spots on first four abdominal
segments as in Gammarus locusta.

Length 6 mm. A few specimens from New Haven measured
14 mm.

Distribution: Cape Cod to Florida. Within Connecticut it
has been reported from Noank, at the surface and in eel-grass,
and from New Haven.

The species occurs often in ees, water and is common
among alge. Two specimens in Peabody Museum were obtained
from the branchial cavity of Mya. Smith records this species
from the stomach of the tomcod and spotted flounder.

DEXAMINID-.

Fifth and sixth segments of abdomen fused.

First antenne with second joint of peduncle long; without
accessory flagellum.

Mandibles without palp. First maxillze with inner plate
having only one or two sete. Second maxilla with inner plate
the smaller, and not fringed on inner margin. Maxillipeds with
outer plates very long and palp rather short with fourth joint
either small or wanting.

First and second gnathopods feeble, subchelate. Pereiopods
with dactyls all commonly pointing backwards.

Third uropods with rami subequal and extending beyond
second pair. Telson elongate, deeply cleft.

Dexamine Leach.

Body comparatively stout with some of the segments elevated
to strong, dorsal projections. Last two segments of abdomen
completely fused. Coxal plates increasing in height to fourth
pair; fifth pair much larger than succeeding pairs.

Antennze very slender; first pair with peduncle much
elongated and without accessory flagellum; much longer in the
female than the second which, however, in the male is greatly
prolonged.

Mandibles without palps. First maxille with inner plate very
small and bearing a single seta apically ; palp uniarticulate though
rather large. Maxillipeds with outer plates very large, nearly
concealing the comparatively small and slender palps.

116 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Gnathopods not very strong and somewhat unequal, the second
pair being more elongated than the first; propodus in both pairs
considerably dilated in middle and distinctly subchelate.

Last pair of uropods of moderate size with rami subequal
and narrow lanceolate in form. ‘Telson much elongated and
deeply cleft with lateral edges spinous.

Dexamine thea Boeck.

Fic. 30. Dexamine thea.

1893. Dexamine thea, G. O. Sars, Crust. Norway, vol. 1,
Pp 477, pl. 168h he. 1.

Head produced into a small rostrum; interantennal lobes
large and pointed. Eyes large, compound, oval to pyriform in
shape.

First antenne over half as long as body; first joint of peduncle
stout and nearly as long as second joint,* which is slender,
and three times as long as third; flagellum slender, made up of

~

No. 26.] ARTHROSTRACA OF CONNECTICUT. Ly

twelve to sixteen segments. Second antennz much shorter than
first; last two joints of peduncle subequal in length; flagellum
not exceeding the peduncle in length, composed of five to nine
segments.

First four coxal plates well developed and much deeper than
their segments with lower margins setose.

First gnathopods stouter but shorter than second; carpus
short, subtriangular ; propodus broader than carpus, with oblique,
finely pectinated palm which is as long as hind margin
and separated from it by two large spines. Second gnathopods
with carpus narrowly triangular, with a fascicle of sete at lower
posterior angle; propodus widening regularly toward distal end,
palm oblique, finely pectinated, rounded posterior angle armed
with two stout spines; propodus and carpus taken together form-
ing an elongated triangle. Pereiopods very spiny; dactyl narrow
over half as long as propodus; basal joint of third pair of pereio-
pods expanded and prolonged slightly distally behind; basal
joint of last pair not expanded.

First four abdominal segments armed dorsally with a strong
posterior spine. Postero-lateral angle of third segment produced
and acute.

Second pair of uropods much shorter than first or third; rami
provided with a long terminal spine and several shorter lateral
ones ; terminal uropods extending a little beyond first pair; rami
subequal, flattened, much longer than peduncle.

Telson much elongated, extending nearly to tip of posterior
uropods, cleft nearly to base; lobes denticulated at apex and
furnished with several tufts of spines near lateral margins and one
or more at distal end.

Length 3 mm.

Distribution: Norway; British Isles; France; Woods Hole,
Massachusetts; Noank Harbor (taken at the surface in the
evening, July 13, 1874), off Stonington, Connecticut ; Long Island
Sound.

ORCHESTITDAS:

Mouth parts strongly projecting downwards.

First antennz usually much shorter than second pair; without
accessory flagellum. Second antennz with first joint of peduncle
coalesced with the head.

118 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Mandibles without palp. First maxille with inner plate
slender and tipped apically with two plumose sete; palp uni-
articulate, small.

Second gnathopods in the male either feebly chelate or more
usually strongly subchelate; in the female either feebly chelate

or subchelate.
Third uropods usually with a single ramus. Telson usually

short.
Orchestia Leach.

First pair of coxal plates small; fifth pair almost as deep as
the preceding and deeply bilobed.

First antennz very small, much shorter than peduncle of
second which is elongated and subpediform and has the first two
joints coalesced with the head and not provided with a gland cone.

Mandibles without palp. First maxille with only a slight
rudiment of a palp. Maxillipeds with the triarticulate palp
short and broad. .

First gnathopods small, subchelate in both sexes, the pro-
podus with a distinctly defined palm. Second gnathopods very
dissimilar in the two sexes; in female feeble, with an imperfectly
chelate propodtus and ‘rudimentary dactyl; in male very strongly
developed, with subchelate propodus.

Terminal uropods with a single minute ramus. Telson short,
thick, and broad, rounded at the tip.

Orchestia agilis Smith.

1874. Orchestia agilis, Smith, Rep. Com. Fish. for 1871-2,
P. 555 pl. 4, fig. 14.

Eyes large.

First antennz very short, not reaching as far as penultimate
joint of peduncle of second pair; flagellum shorter than peduncle
and made up of three or four segments. Second antennze less
than half as long as body; peduncle stouter in male than in
female with last joint slightly longer than preceding; flagellum
shorter than peduncle and made up of ten or fifteen short
segments.

First pair of coxal plates higher than long and considerably
smaller than second pair.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 119

Fic. 31. Orchestia agilis.

First gnathopods of male subchelate, with carpus longer than
propodus and provided with a prominent rounded lobe at distal
end of posterior margin; propodus widened distally, with infero-
posterior angle produced into large rounded lobe against which
the dactyl closes, distal end of propodus rather deeply notched.
Second gnathopods with large oval propodus and small carpus;
palm of propodus oblique and convex, slightly notched near
posterior end; dactyl long and curved. In female, first gnatho-
pods simple, with propodus shorter than carpus and tapering
slightly distally. Second pair with carpus rounded on posterior
margin ; propodus shorter than carpus, oval, with a minute dactyl
articulated on anterior margin and not reaching distal end of
segment.

12c CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Fifth pair of pereiopods of adult males with merus and carpus
greatly swollen.

Rami of first uropods considerably shorter than peduncle;
second pair with rami subequal to peduncle ; third pair with ramus
much more slender than peduncle and nearly as long. Telson
narrowly rounded behind.

The color of this species is very variable from olive brown
and dark green to whitish. The legs, coxal plates, and posterior
portions of the body are bluish, and the antenne are reddish or

reddish brown.
Length 10 mm.
Distribution: Atlantic coast of North America from the Bay

of Fundy to New Jersey; Bermuda; the Mediterranean; New
Haven, Connecticut ; Long Island Sound.

This species is exceedingly abundant under seaweed near high-
water mark but not so high on the beach as Talorchestia longi-
cornis. It is usually at least a few inches beneath the surface
where the weeds are damp, and when masses of seaweed are up-
turned, the air fairly swarms with these animals, which hop about
with great rapidity and to relatively great distances. It is by far
the most active of the sand fleas. It also burrows in the sand
and is occasionally found on piles at some distance from shore.
It feeds mainly on decaying seaweed but also partakes of animal
food.

Although the species is generally found on shore, it is able
to swim actively. It is strongly attracted by a light and large
numbers may be obtained by placing a. lantern on the beach
along side of a vessel of sea water or alcohol and simply stirring
up the seaweed within a radius of several yards. The animals
hop towards the light and when they fall into the water they are
unable to crawl up the smooth sides of a bucket or glass dish.

Holmes gives a full account in the American Journal of
Physiology, vol. 5, p. 211, of the phototaxis of this species which
may be negative under certain conditions.

Orchestia palustris Smith.
1874. Orchestia palustris, Smith, Rep. Com. Fish. for 1871-2,
P- 555-
First antenne reaching slightly beyond penultimate joint of
peduncle of second antenne; flagellum as long as peduncle.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 121

Second pair with slender peduncle not as long as flagellum, fourth
joint two-thirds as long as fifth.

First pair of coxal plates quadrate and as long as high.

First gnathopods of male-as in preceding species. Second
pair with large oval propodus, having palm very oblique, evenly
convex and spinous, and with a slight process at posterior end
against which the tip of the dactyl fits. In female, first gnatho-
pods similar to those of O. agilis; second pair with basal joint
somewhat broader and more rounded in front but otherwise
very much like the preceding species. Pereiopods four and five
with carpus slender even in the largest males.

\

SECO

Fic. 32. Orchestia palustris.

Postero-lateral angles of second and third abdominal segments
produced into acute points.

First uropods with rami shorter than peduncle; second pair
with rami equal to peduncle; terminal pair with a single ramus
which is longer than the peduncle and relatively larger than in
O. agilis. Telson bearing a posterior notch, lobes rounded and
spinous,

122 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [| Bull.

Color, olive brown to olive green, occasionally reddish-brown ;
antenne, reddish-brown.

Length of female 18 mm., of male 22 mm. ;

This species is readily distinguished from the preceding by
its larger size, longer first antenne, and more slender second
antennz, and by the larger size of first coxal plates.

Distribution: Cape Cod to New Jersey; coast of Texas; New
Haven, Connecticut.

The habitat of this species is different from the preceding,
being usually in the neighborhood of salt marshes and often quite
far from the shore in almost dry places among grass and weeds.
This species crawls more readily than agilis but is a weaker
hopper.

For a fuller account of its habits the reader is referred to
Miss Smallwood’s contribution in the Cold Spring Harbor Mono-
graphs, No. 3, 1905. ;

Talorchestia Dana.

Sunilar to Orchestia except that first gnathopods in female
are simple instead of subchelate and second pereiopods usually
have inner margin of dactyl more sharply constricted than in
allied genera.

Talorchestia longicornis (Say).

1818. Talitrus longicornis, Say, Jour. Acad. Nat. Sci. Phila.,
vol. I, pt. 2, p. 384.

1874. Talorchestia longicornis, Smith, Rep. Com. Fish., vol.
T, pe 550.

Eyes large and circular,

First antenne short, extending slightly beyond penultimate
joint of second pair which is one-third as long as body in female,
but which may equal the length of the body in the male: flagel-
lum multiarticulate and longer than peduncle.

Mouth parts forming a conspicuous projection on ventral side
of head, extending below the level of the coxal plates. Mandibles
without palp. Maxillipeds with triarticulate palp.

Coxal plates increasing in height and length from the first to
the fourth, but not so high as their respective segments, their ven-
tral margins slightly rounded and provided with numerous short

No. 26.] ARTHROSTRACA OF CONNECTICUT. 123

setze ; fifth, sixth, and seventh plates decreasing in size posteriorly.
First three abdominal segments with postero-lateral corners rec-
tangular or slightly acute.

Fic. 33. Talorchestia longicornis.

First gnathopods in male with carpus produced at postero-
distal angle to form a long, rounded lobe; propodus shorter than
carpus, widening somewhat distally and with postero-distal angle
slightly rounded and produced and covered with dense spines,
palm transverse and short. Second gnathopods of male with pro-
podus large and oval with anterior margin rounded and posterior
one nearly straight, palm oblique, defined by a blunt tooth, be-
tween which and the hinge is a convex lobe provided with setz.
In female the first gnathopods resemble those of male but the
carpus lacks the rounded process and the propodus tapers distally
so that there is no distinct palm. Second gnathopods weak, basal

124 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

joint very broad, with anterior margin strongly convex and pro-
vided with short sete; propodus oblong, with anterior margin
slightly concave and shorter than posterior one, distal end
rounded ; very weakly chelate ; dactyl rudimentary. Second perei-
opods "oe than first; third pair very short and with basal
joint néarly circular; fourth and fifth pairs short and stout.

First uropods extending slightly beyond second, with rami
subequal in length to each other and to peduncle; second pair
with rami longer than peduncle and with inner ramus considerably
longer than outer; terminal uropods with single ramus as long as
peduncle but much narrower. Telson triangular, fleshy, emar-
ginate. :

Color grayish or sand-colored. Antenne pinkish or red at
base, flagellum blue.

Length 20 mm.

Distribution: Cape Cod to New Jersey; New Haven, Con-
necticut.

This species is usually quite abundant on sandy beaches at or
above high-water mark where the animals burrow beneath the
surface in order to reach moist sand. The species is nocturnal
in its habits and in the daytime the individuals remain quiet in
their burrows and their presence is indicated only by small holes
in the sand. In the night they run about over the seaweed that
has recently. been washed ashore and which furnishes their prin-
cipal food. The species is strongly attracted by a light and may
be gathered in large numbers simply by placing a lighted lantern
in the middle of a sheet spread on the beach where they are
known to be. When dug out of the sand in the day, Talorchestia
is rather sluggish and may feign death, but when aroused it
makes a few leaps and if it alights on loose sand it remains quiet
a moment and then very quickly begins to burrow.

Talorchestia is capable of swimming rapidly when driven out
of its burrows by a particularly high tide.

Miss Smallwood in Cold Spring Harbor Monographs No. 1,
pee has described the habits and variations of the species quite

ully.

Specimens bearing eggs have been found at Woods Hole in
July and August.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 125

Talorchestia megalophthalma (Bate).

Fic. 34. Talorchestia megalophthalma.

1862. Orchestia megalophthalma, Bate, Catalogue Amphip-
odawbrit Mus..p. 22.pl. 4, fie. 8

1874. Talorchestia megalophthalma, Smith, Rep. Com. Fish.,
vol.h,ps1550:

Eyes very large, covering almost entire side of head.

First antennz short, with flagellum shorter than peduncle,
extending as far as penultimate joint of peduncle of second
antenne, which are shorter than those of 7. longicormis.

First gnathopods of male with propodus tapering slightly to
distal end where posterior margin bears a rounded lobe, no dis-
tinct palm; carpus with prominent lobe near distal end of poste-
rior margin. Second gnathopods of male with large ovate pro-
podus having palm evenly convex and with prominent lobe poste-
riorly bearing a strong spine. Gnathopods of female very similar
to those of T. longicornis.

j

126 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Second abdominal segment with se angle produced
into a small acute triangular process.

First uropods with rami equal and about as long as peduncle;
second pair with rami longer than peduncle and with inner ramus
longer than outer; terminal pair with ramus slightly longer than
peduncle.

Length 15 mm.

Miss Smallwood, in Cold Spring Harbor Monographs, No. 1,
regards this species and the preceding as different stages of the
same form, me egalophthalma being a younger stage of longicorms.
Aside from the difference in the length of the antennz, however,
upon which Miss Smallwood bases her conclusions very largely,
the two species differ from each other in the size of the eyes,
the different form of the second gnathopod of the males, the
longer ramus of the third uropod of megalophthalma, and by the
triangular process on the postero-lateral angle of the second
abdominal segment.

Distribution: This species has the same range as the preced-
ing and occurs in similar situations but is far less common than
longicornus. Noank and New Haven, Connecticut.

Hyale H. Rathke.

Fourth coxal plates much deeper than fifth. First antennz
longer than peduncle of second.

First maxilla with uniarticulate palp reaching to base of
apical spines of outer plate. Maxillipeds with four-jointed palp.

Second gnathopods in male with carpus small and masked
behind by the merus; in female carpus produced ae between
adjacent segments.

Third uropods uniramous. Telson unarmed, divided to base.

Hyale prevostii (Milne-Edwards).

1830. Amphithoe prevostii, Milne-Edwards, Ann. d. Sci.
Nat. vol. 20, p. 378.
1888. Hyale prevostii, Stebbing, Rep. Voy. “ Challenger,”
vol. 29, p. 144.
Back smooth, coxal plates with lower margins smooth; first
pair widened below.
' Eyes small, round.

CONNECTICUT.

ARTHROSTRACA OF

Fic. 35. Hyale prevostii.

128 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

First antenne as long as head and first segment of thorax
together, extending well beyond the peduncle of second antenne ;
peduncle with joints becoming successively smaller; flagellum
longer than peduncle and made up of about ten joints. Second
antenne with last joint of peduncle the longest; flagellum longer
than peduncle and made up of about a dozen segments.

First gnathopods in the male with short, stout basal joint,
scarcely twice as long as wide; carpus triangular, with short,
posterior margin strongly convex and armed with many sete;
propodus subrectangular with front margin strongly convex,
about twice as long as wide, palm slightly oblique and convex;
dactyl stout and curved. Second gnathopods very large; basal
joint stout and expanded below in front; merus bearing a tri-
angular process distally; carpus very small and inconspicuous ;
propodus large and oval, palm oblique and convex, armed with a
row of short spine teeth, prehensile angle prominent but rounded.

In the female the two pairs of gnathopods are of the same
form, but the second pair is slightly larger than the first and the
carpus of the first is relatively longer than that of the second;
propodus subrectangular with fascicle of spines at middle of
posterior margin, dactyl longer than palm. Pereiopods stout, and
provided with numerous spines and sete. Third to fifth pereio-
pods with basal joint expanded and hind margin smooth. Fourth
and fifth pairs with propodus armed with a spine at the middle
of the hind margin.

Postero-lateral angle of third abdominal segment very slightly
produced, forming less than a right angle.

First uropods extending beyond the others; rami short and
spinous on margins and apex. Terminal pair small, with ramus
much shorter than peduncle.

Telson divided into two obtuse lobes.

Length 6-8 mm.

Distribution: Atlantic coast of Europe; Azores; Bermuda;
Noank, Connecticut, low water, Aug. 29, 1874, and Long Island
Sound.

Hyalella Smith.

Similar to Hyale except that first maxilla have a smaller palp
not reaching the base of apical spines of outer plate. Second

~

No. 26.] ARTHROSTRACA OF CONNECTICUT. 129

=

gnathopods in male with carpus produced behind between merus
and propodus. Telson entire.

Hyalella knickerbockeri (Bate).

Fic. 36. Hyalella knickerbockeri.

1862. Allorchestes knickerbockeri, Bate, Cat. Amphipoda.
Brit. Mus., p. 36, pl. 6.

1874. Hyalella dentata, Smith, Rep. U.S. Fish. Com., 1872-3,
p. 645, pl. 2.

1907. Hyallela knickerbockeri, Weckel, Proc. U. S. Nat.
Mus., vol. 32, p. 54.
| g)

130 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Eyes nearly round, their distance apart slightly greater than
their diameter.

First antenne shorter than second pair; first and second
segments of peduncle subequal in length and slightly longer than
third; flagellum about twice as long as peduncle and made up
of seven to nine joints. Second antennz half as long as the body ;
peduncle exceeding that of the first pair; last two joints elongated
and subequal; flagellum usually only slightly longer than that of
first pair.

First gnathopods in the male with carpus longer than pro-
podus and having a rounded lobe posteriorly densely setose; pro-
podus more than half as long as wide, subrectangular, provided
with a group of short cilia near the distal end of front margin
and a fascicle of long ones at the apex; palm nearly trans-
verse, slightly sinuous and provided with a prehensile spine;
dactyl strongly curved and shorter than palm. Second gnatho-
pods in the male with enormous oval propodus; carpus short,
with a long, slender lobe extending along the posterior margin
of propodus which is more than half as broad as long, palm
oblique, the middle portion slightly arcuate and provided with a
notch near the middle, armed with a submarginal row of spines,
prehensile angle prominent, rounded. Second gnathopods of
the female elongated, weak; carpus wider than propodus with
small, rounded lobe behind, provided with a group of sete;
propodus somewhat curved and broadest distally, more than twice
as long as broad, posterior margin prolonged to form a chela with
the dactyl, which is shorter than the palm and not strongly
curved. Posterior margin of basal joints of last three pereiopods
serrate.

Postero-lateral angles of third abdominal segment produced
slightly to form a triangular tooth; first two or three segments
usually produced dorsally to form a well marked posterior tooth
on the middle line.

First uropods almost twice as long as the second pair. Ter-
minal pair very short, not exceeding the peduncle of the second
pair in length; peduncle very short, nearly as broad as long,
furnished distally with a few sete: ramus tapering, as long as
peduncle, with a few sete at apex. Telson short, entire, nearly
as broad as long and furnished with a slender seta on each side.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 131

Length 7 mm.

Very abundant in streams, lakes, and stagnant pools through-
out the entire United States. New Haven and Canaan,
Connecticut. j

Allorchestes Dana.

First antenne longer than peduncle of second.

First maxille with uniarticulate palp. Maxillipeds with four-
jointed palp.

Second gnathopods in male with carpus produced behind
between the adjacent segments.

Telson more or less divided.

Allorchestes littoralis Stimpson.

Fic. 37. Allorchestes littoralis.

— 1853. Allorchestes littoralis, Stimpson, Marine Invert. Grand
Manan, Smithson, Contrib. Knowl., vol. 6, No. 5, p. 49, pl. 3,
fig. 36.

1874. Hyale littoralis, Smith, Rep. Com. Fish., vol. 1, p. 556.

Eyes oval, moderately large, situated rather close together.

First antenne three-fourths the length of second with the
three joints of peduncle of subequal length; flagellum longer than
peduncle and made up of nine to thirteen joints. Second antenne
less than half the length of body, last joint of peduncle slightly
longer than preceding one, the lower side furnished with a large
tuft of plumose spines.

First gnathopods much alike in the two sexes; merus pro-
duced distally into a prominent setose angle; carpus with posterior
lobe oblong, rounded, and thickly setose; propodus oblong, widen-

132 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

ing distally, palm slightly convex and nearly transverse, prehen-
sile angle armed with two short, stout spines, posterior margin
with a setose convexity just distal to the middle, dactyl closely
fitting palm, with a single short seta on outer margin near base.

Second gnathopods stout in male; basal joint elongated and
concave anteriorly; merus twice as long as ischium and strongly
produced distally into a pointed lobe; carpus with posterior lobe
very long and narrow; propodus large, oval, palm oblique and
evenly convex with two short, stout spines at prehensile angle,
posterior margin with a small setose convexity near the palm;
dactyl much as in first gnathopods. In female the posterior lobe
of carpus not nearly so narrow and propodus smaller and more
oblong than in male; palm more oblique than in first gnathopods.

First and second uropods with rami subequal to peduncle;
first pair with peduncle armed above with two rows of three or
four spines each, last spine of inner row enormously developed
about two-thirds the length of rami; each ramus with two spines
on upper margin and a cluster at the tip. Peduncle of last uro-
pods very short and stout, with a single stout spine on upper
margin; ramus as long as peduncle but much narrower, furnished
with a cluster of spines distally.

Telson deeply bilobed.

General color, green to olive-brown; antenne reddish brown;
eyes black.

Length 6 mm.

Distribution: Grand Manan to Long Island Sound; New
Haven, Connecticut (Smith).

This species occurs on rocky shores high up on the beach
near high water; on piles, and in tide-pools. It approaches a
terrestrial habit like Orchestia, as it can walk upright with some
difficulty while out of water and hops quite readily.

AORID-.

Fourth coxal plate not excavate behind.
First antenne longer than second; third joint of peduncle
short; accessory flagellum present.

First maxilla with a single seta on inner plate; second joint
of palp elongate.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 133

First gnathopods larger than second and showing consider-
able differences usually in the two sexes. First and second pereio-
pods glandular. Last pair of pereiopods the longest.

Terminal uropods biramous, not elongate. Telson simple.

Microdeutopus Costa.

Body slender, slightly compressed ; coxal plates comparatively
small.

Mandibles strong, with palp of moderate size and having
terminal joint slender. First maxillz with inner plates small and
furnished with a single apical seta. Maxillipeds with palp not
very large.

First antennz longer than second and provided with a distinct
accessory flagellum.

Gnathopods in female comparatively small, the first pair
being a little larger than the second pair; propodus imperfectly
subchelate; that of second pair narrow and with palm nearly
transverse and very short. First gnathopods in male greatly
developed and with carpus extremely large and swollen, forming
with the propodus and dactyl a kind of chela. First and second
pereiopods glandular. Three posterior pereiopods rapidly in-
creasing in length and with basal joint but little expanded.

Terminal uropods not extending beyond the others; rami
sublinear and sparsely spinous. Telson large and thick, oval
with a dorsal fascicle of spines on either side of the obtusely
rounded tip.

Microdeutopus gryllotalpa Costa.

1853. Microdeutopus gryllotalpa, Costa, Rendiconto d. Soc.
Reale) Borbenica, Ac. d:) Sei, n. ser., vol. 2p. 178: .

1873. Microdeutopus minax, Smith, Rep. U. S. Com. Fish.,
VOl.<1s p. 562,

1896. Microdeutopus gryllotalpa, G .O. Sars., Crust. Norway,
vol. 1; p2543, pl. 102, fig. 2:

Eyes small, round, deeply pigmented.

First antennz more than half as long as body; second joint of
peduncle a little longer than first and as long as head, third joint
short; principal flagellum slender, of about twenty segments and
longer than peduncle; accessory flagellum one-jointed and not as
long as first joint of principal flagellum.

134 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Second antennz three-fourths as long as first, with fourth and
fifth joints of peduncle subequal and nearly twice as long as
third; flagellum slightly longer than last joint of peduncle and
made up of seven joints.

Fic. 38. Microdeutopus gryllotalpa,

=

In male: first gnathopods very strong ; carpus oval and longer
than basal joint, posterior margin produced to form a prominent

No. 26.] ARTHROSTRACA OF CONNECTICUT. 135

triangular process proximal to which are two smaller ones; pro-
podus twice as long as wide, tapering slightly, posterior margin
very irregular, bearing several rounded prominences; dactyl long
and slender. Second gnathopods with basal joint irregularly oval
in form with front margin crenulated; carpus long and slender,
rectangular; propodus subrectangular, slender, not as long as
carpus, palm slightly oblique; dactyl short; carpus and propodus
densely setose.

In female: first gnathopods not as strong as in male; carpus
broadly oval; propodus suboval, slightly longer than carpus but
narrower, palm straight, oblique, with prehensile spine.

Third pereiopods very short, fourth and fifth increasing in
length and with basal joints expanded.

Coxal plates lower than their respective segments; first pro:
jecting well forward to form a slender triangular process.

First pair of uropods extending as far posteriorly as last pair,
with the peduncle and subequal rami provided with stout spines
on dorsal margin; rami styliform and equal in each case to the
peduncle in length. .

Telson broadly oval, slightly longer than broad and with
rounded apex provided with a group of three spines at the
postero-lateral angle.

Body densely variegated with a dark brownish pigment.

Length 8 mm.

Distribution: European coast from Norway to the Mediter-
ranean; Provincetown (Rathbun) ; Woods Hole, Massachusetts ;
Vineyard Sound; New Haven (Smith), Noank, Noank Harbor,
Connecticut ; Long Island Sound.

The species occurs among hydroids and alge, on piles and in
eel-grass. A few specimens in the collections studied, had been
taken at the surface, Noank Harbor, in the evening, July 13, 1874.

Microdeutepus damnoniensis (Bate).
1856. Lembos damnoniensis, Bate, Rep. Brit. Assoc., Meet-
M225, P.-56, pl. 17; fie.
1903. Microdeutopus damnoniensis, Holmes, Amer. Natural-
ist, vol. 37, p. 290.
1905. Microdeutopus damnoniensis, Holmes, Bull. U. S. Bur.
Fish., vol. 24, p. 515.

136 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

This species may be readily distinguished from the preceding
one by the biarticulate accessory flagellum of the first antenne ;
by the more slender first gnathopods of the male, the more
elongated carpus, and different form of the carpal process which
is narrowly triangular, acute, and with a small tooth near the base
of the posterior margin; by t the less elongated propodus of the
second gnathopods; and the longer and more slender terminal
pereiopods. ,

Length 6 mm.

The species has been recorded from Norway, the British Isles ;,
and Woods Hole, Massachusetts.

Lembos Bate.

Body slender, coxal plates of medium depth.

First antenne much longer than second with flagellum long
and accessory flagellum well developed.

Lower lip with mandibular processes strongly produced.
Mandibles with both incisive plates dentate, molar tubercle
strong ; third joint of palp longer than second. First maxillze with
inner plate small and bearing a single apical seta; second joint of
palp with several spine-teeth. Maxillipeds with plates generally
well developed; fourth joint of palp not stout.

First gnathopods in male with merus not elongate ; carpus and
propodus stout, subequal in width, strongly setose, palm of latter
with tooth-like projections. First and second pereiopods glandu-
lar. Posterior pereiopods with basal joint not very widely
expanded.

Third uropods with rami much longer than peduncle and
equal. Telson simple.

Lembos smithi (Holmes).

1903. Autonoe smithi, Holmes, Amer. Naturalist, vol. 37, p
290.

1905. Autonoe smithi, Holmes, Bull. U. S. Bur. Fish., vol.
2A; poSio:

1906. Lembos smithi, Stebbing, Das Tierreich, Lief. 21.

Eyes oval, deeply pigmented.

First antenne nearly as long as body; first joint of vedanele
as long as head; second joint considerably longer than first and

No. 26.] ARTHROSTRACA OF CONNECTICUT. 137

_ about three times as long as third; principal flagellum slender and
longer than peduncle, provided with abundant sete on lower
margin; accessory flagellum as long as terminal joint of peduncle,
consisting of three joints. Second antennz much shorter than
first, but with longer peduncle; gland cone slender and not large,
third joint twice as long as wide, fourth joint slightly shorter
than fifth, which in turn is as long as the six- or seven-jointed
flagellum.

Fic. 39. Lembos smithi.

Coxal plates small and provided with a few short sete; the
first four subquadrate and much longer than high.

First gnathopods very stout, with basal joint short, not more
than twice as long as broad; carpus as broad as long and cup-
shaped, posterior margin densely setose; propodus broader and
longer than carpus; oval in form, with palm sinuous, posterior
angle prominent and armed with a stout,spine, posterior margin

138 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.
short and marked by two prominences ; dactyl stout and provided
with many minute blunt teeth. Second gnathopods longer and
more slender than first; carpus densely setose, triangular with
anterior margin strongly convex; propodus also densely setose,
rectangular and about as wide as carpus but scarcely as long,
palm short, transverse, convex with a spine at rounded posterior
angle ; dactyl provided with several short setee on concave margin.

First two pereiopods with spinning glands and basal joints
long and narrow ; merus broadened distally and projecting beyond
the carpus which is equal in length to the propodus; terminal
joint very slightly curved. Third, fourth, and fifth pereiopods
increasing successively in length; second joints slender.

Postero-lateral angles of first three abdominal segments
rounded.

First pair of uropods slender, with rami equal to the peduncle
which bears a slender, curved projection nearly half as long as
rami; second uropods extending as far as first and of similar
form but with much shorter peduncle; third uropods with rami
which are much longer than the peduncle and provided distally
with long slender spines ; peduncle without terminal prolongation.
Telson thick, rounded distally, wider than long and with several
long setz.

Holmes describes the color as follows: “body and coxal
plates with blackish pigment, the fifth thoracic segment lighter
than the others: abdomen lighter than thorax; legs transparent
and almost devoid of pigment; body and appendages with a
diffuse reddish-brown coloration, which is deeper on the large
hand, becoming more intense toward the tip and on the base of
the dactyl; dorsal side of body crossed with purple, orange, or
rose-colored bars; both pairs of antenne very beautifully and
conspicuously marked with spots of red, pink, or orange, these
spots on the peduncles of both antenne at the base of the sete,
on the flagellum of first antenne; they are regularly arranged,
a pair of oblong spots being separated by a colorless longitudinal
interval on each joint.” .

Length 6 mm.

Distribution : Cape Cod to Hatteras, Vineyard Sound (Smith),
“in tubes, in masses of a compound ascidian (Amouroucium
pellucidum) in 3-8 fathoms” (Verrill) ; Long Island Sound.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 139

PHOTIDAS,

Fourth coxal plates not excavate behind.

First antennz sometimes as long as second, sometimes longer;
accessory flagellum varying from long to obsolete.

First and second gnathopods either subchelate or simple; first
never larger than second. First and second pereiopods glandular.
Fourth and fifth pereiopods longer than the others.

Terminal uropods uniramous; first and second biramous.
Telson simple.

Photis Kroyer.

Posterior abdominal segments elongated and slender. Ante-
rior pairs of coxal plates comparatively large and closely con-
tiguous ; fifth pair scarcely smaller than preceding pairs.

Eyes small. Antennz subequal, and generally densely setifer-
ous posteriorly, peduncles elongated; first pair with no accessory
flagellum.

Mandibles with elongated palp having terminal joint compara-
tively short and densely setose.

Gnathopods distinctly subchelate ; the second pair being some-
what larger than the first pair. First and second pereiopods
glandular. Third pereiopods stout and strongly reflexed, with
basal joint boldly curved anteriorly and dactyl inverted.

Last pair of uropods slender and extending beyond others;
rami very unequal, the inner one being very minute, the outer
one elongated and having a small terminal joint. Telson ex-
tremely small, triangular.

Photis reinhardi Kroyer.

1842. Photis reinhardi, Kroyer, Naturh. Tidsskr., vol. 4,
Pp. 155. . i

1894. Photis reinhardi, G. O. Sars, Crust. Norway, vol. 1
p. 569, pl. 202. |

Eyes elongated, situated on prominent interantennal lobes;
head not as long as first two thoracic segments together. First
coxal plates somewhat attenuated distally and rounded at the
tip. Second to fifth coxal plates taller than their respective *
segments ; fifth bilobed, posterior lobe small.

140 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Fic. 40. Photis reinhardi.

Antenne stout and setose. First antenne half as long as body
and a little longer than second pair; second joint of peduncle
the longest; third joint a little longer than first which is much
stouter than the succeeding ones ; flagellum of about eight joints,
more than half as long as peduncle. Second antenne with flagel-
lum of about six joints, not as long as last two joints of peduncle.

First gnathopods of female robust, with carpus expanded
behind into a broad lobee provided with long sete; propodus a

No. 26.] ARTHROSTRACA OF CONNECTICUT. 141

‘

little longer than carpus, broad, oval quadrangular in form; palm
oblique and convex and longer than hind margin; dactyl strong
and denticulated within. Second gnathopods more strongly built
and with larger propodus than first pair; carpus short, with lobe
much narrower than in first pair; propodus with the palm some-
what sinuous and defined behind with a distinctly projecting
angle and a stout spine; dactyl stout, with several serrations
within. Gnathopods in the male considerably stronger than in
female, with propodus comparatively larger; palm of first pair
slightly excavated; in the second pair much shorter than the
hind margin and defined by a strong acuminate process. Pereio-
pods stout. Third pair with propodus slightly expanded distally
forming a kind of palm armed with a slender spine against which
the short, stout dactyl strikes; last two pairs of nearly equal
length, with basal joints oblong oval in form.

Last pair of uropods with the outer ramus scarcely as long as
peduncle, biarticulate, with terminal joint very minute and tipped
. with a long spine; inner ramus minute. Telson less than twice
as broad as long, triangular in form.

Length 5 inm.

Distribution: Arctic Ocean, Greenland, Iceland, Norway. I
met with a single female specimen from Long Island Sound in
the collection.in the U. S. National Museum obtained from the
region about Noank, Connecticut.

Podoceropsis Boeck.

Antennz slender and subequal in length, peduncles elongated,
densely setiferous, no accessory flagellum.

Mandibular palps elongated and densely setose. Other mouth
parts normal.

Gnathopods very unequal, the first pair being feeble; the
second pair being much larger and very powerfully developed in
male. Posterior gnathopods with basal joint moderately ex-
panded. First two pereiopods glandular.

Last pair of uropods scarcely extending beyond the others;
tami subequal. Telson rounded, tubular.

=
CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

142
Podoceropsis nitida (Stimpson).

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Podoceropsis nitida.

FIG: AT.
Podocerus nitidus Stimpson, Smithson. Contr. Knowl,,

1853.
vol. 6, No. 5, p. 45.
1877. Podoceropsis excavata (Bate), Méinert, Naturhist.

Wdskre ((3'); walt vi jope eS ot
Eyes oval, situated on rather prominent, acutely pointed inter-
antennal lobes.
Antenne subequal in length, exceeding somewhat half the
First antenne with

length of the body, and strongly setose.
basal joint of peduncle stout and scarcely as long as third joint;

No. 26.] ARTHROSTRACA OF CONNECTICUT. 143

second joint much longer than third; flagellum about as long as
peduncle. Second antenne with fourth and fifth joints of pedun-
cle subequal in length, third joint hardly twice as long as wide;
flagellum shorter than peduncle.

First two pereiopods with spinning glands; fifth coxal plate
taller than fourth and with a small posterior lobe.

First gnathopods quite slender; carpus elongated and slender,

setose ; propodus shorter and narrower than carpus, more or less

fusiform; palm not marked off distinctly from posterior margin;
dactyl very long and curved, closing against entire posterior
margin. Second gnathopods large; carpus very short and cup-
shaped; propodus strong, suboval, palm finely tuberculated and
oblique, with a rather deep rounded excavation at middle which
is bounded by angular prominences, posterior margin setose;
dactyl strong and curved, scarcely reaching posterior angle of
palm. The male differs from the female in the fact that the
angular prominence of the palm toward the hinge is broadly
truncate and slightly emarginate, and the excavation is narrower
than in the female.

First and second pereiopods with meral joints nearly as long
as carpus and propodus combined. Third pereiopods with basal
joint nearly as broad as long.

-Postero-lateral angles of third abdominal segment with a
very small projection.

First uropods with peduncle considerably longer than the
styliform rami and with ventral margin prolonged to form a
slightly curved spine projecting below rami; third uropods with
rami equal in length to peduncle, extending as far posteriorly as
first but not quite so far as second, inner ramus slightly longer
than outer.

Telson as broad as long with group ‘of three sete on each

side of rounded apex.

Length 7 mm.

Distribution: Norway.; British Isles; Grand Manan; Eastport,
Maine; Rhode Island; Long Island Sound.

The species occurs at depths of 30-40 fathoms.

Leptocheirus Zaddach.
Posterior portion of abdomen strongly built? Second pair
of coxal plates greatly expanded.

144 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

First antennz longer than second, with well developed acces-
sory flagellum.

Mandibles and maxille Hecme Maxillipeds comparatively
large, with inner and outer plates small, and palp very slender
with third joint very much elongated.

Gnathopods unequal in structure; first pair distinctly sub-
chelate with ischium laminarly expanded. Second pair slender
with dense sete along front edge; carpus large; propodus short
and tapering without a distinct palm. First two pereiopods
glandular and with propodus unusually slender and elongated.

First and second uropods robust, and armed with strong
unguiform spines; last pair small. Telson small and tubular.

Leptocheirus pinguis (Stimpson. )

1853. Ptilocheirus pinguis, Stimpson, Smithson. Contrib.
Knowl., vol. 6, No. 5, p. 56.

1888. Leptocheirus pinguwis, Stebbing, Rep. Voy. “ Chal-
lenger,” vol. 29, p. 279.

Body broad. Eyes oval or reniform.

First antennz longer than second pair but not so stout, last
joint of peduncle short, second joint longer than the first; prin-
cipal flagellum slender, composed of twenty or more segments,
longer than the peduncle; accessory flagellum well developed.
Second pair of antenne with flagellum about one and a half times
as long as last peduncular joint.

First gnathopods larger than the second ; coxal plate prolonged
considerably anteriorly ; carpus rectangular and as long as pro-
podus, with dense sete on posterior margin; propodus slightly
broader distally than proximally, palm transverse, posterior
margin with dense sete; dactyl short and curved; carpus bent
inward at nearly right angles to the proximal joints. Second
gnathopods with basal joint slightly rounded in front and fringed
with very long plumose spines; carpus longer than propodus
and somewhat broader, provided with very thickly set sete on
hind margin; propodus slightly tapering in form, with short palm
and with hind margin densely covered with long sete. First and
second pereiopods with spinning glands, and subequal in size;
third, fourth, and fifth periopods with basal joints well rounded
and increasing in length posteriorly.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 145

Fic. 42. Leptocheirus pinguis.

146 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. , [Bull.

Uropods biramous; terminal pair projecting beyond the
others, rami armed dorsally and apically with groups of spines;
peduncle with group of spines on upper apex. Peduncles of
first and second pairs with a long, curved, claw-like projection
distally, extending beneath the rami. Telson broader than long,
apex rounded, undivided, postero-lateral angles with a tuft of
spines in front of which is a row of three or four short spines.

Fourth and fifth abdominal segments provided with a group
of short spines near posterior margin at either side of middle
line. ?

The color of this species is highly characteristic even in
alcoholic specimens in which the head, body segments, the coxal
plates especially in the proximal region, and the basal joints
of the posterior pereiopods, are marked with chocolate brown
granules. These markings on the body are usually in the form
of broad transverse bands which may enclose irregular lighter
areas. There is much variation in the amount of pigmentation.
The eyes of alcoholic specimens are black.

Length 13 mm.

Distribution: east coast of North America from New Eng-
land to Labrador; off New London, off Stonington, off Saybrook,
Noank, Connecticut ; off Race Point; Fishers Island, 42 fathoms;
Long Island Sound, 50 fathoms.

This is one of the most abundant of the Amphipoda of the
New England coast; it is especially common on muddy bottoms.
It occurs on the surface and, according to Smith, to depths of
150 fathoms.

AMPHITHOID-:.

Interantennal lobes not very prominent.

Fourth coxal plate not excavated behind; fifth with a broad
front lobe as deep as the preceding.

First antenne with third joint short; accessory flagellum
wanting or small.

Lower lip with principal plates having a deep notch in front
forming a broad sinus.

Gnathopods not simple, second usually larger than the first
and larger in the male than in the female and differently shaped.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 147

First and second pereiopods glandular. Third pereiopods re-
verted. Fifth pair the longest.

Third uropods with short rami, the outer one of which is
uncinate. Telson simple.

Amphithoe Leach.

Body slender, compressed, coxal plates of moderate size.

First antennz without accessory flagellum.

Lower lip with outer plates incised at tip. Mandibles very
strong; palp comparatively short, with terminal joint large and
expanded and setose distally and on inner margin. First maxille
with inner plate small and with a single seta. Second maxillz
with outer lobe much larger than inner. Maxillipeds with moder-
ately short palp.

Gnathopods subchelate. First two pereiopods glandular.
Posterior pereiopods increasing successively in length with pro-
podus simple.

Last pair of uropods with peduncle massive; rami subequal
in length, the outer one lamellar and armed with two unguiform
spines, the inner one conical in form. Telson of moderate size
with a small projection on either side of the tip.

‘Amphithoe longimana Smith.

1874. Amphithoe longimana, Smith, Rept. U. S. Com. Fish.,
1871-2, p. 563.

Body slender. Eyes round and, in life, red.

First antenne slender and as long as body; second joint of
peduncle longer than first and nearly twice as long as third;
flagellum about twice as long as peduncle. Second antenne
stouter than first, especially in male, and somewhat shorter;
peduncle much elongated, last joint considerably longer than
preceding one and about as long as flagellum.

First five coxal plates much deeper than their segments; the
first one prolonged in front; the three following plates oblong.

First gnathopods in male unusually elongated; carpus long
and narrow with sete on hind margin; propodus three times
as long as wide and as long as carpus but hardly as broad, palm
short and transverse, posterior margin slightly ‘concave and
covered densely with sete; dactyl large and projecting well be-

148 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Fic. 43. Amphithoe longimana.

No. 26. ARTHROSTRACA OF CONNECTICUT. a
49

yond the palm. Second gnathopods very strong; carpus sub-
triangular, much shorter than propodus which is oblong and
broader than in first pair, and slightly broader distally than
proximally, front and hind margins setose, palm oblique and con-
cave, with prehensile angle prominent. Gnathopods in female
comparatively small; first pair with propodus oblong and longer
than carpus, and palm oblique and rounded behind where it is
armed with a strong spine; dactyl projecting beyond palm but
not nearly so far as in the male. Second gnathopods with carpus
produced behind into a narrow lobe which is setose distally ; pro-
podus oblong, shorter and broader than in first pair, palm oblique,
prehensile angle rather prominent and armed with a stout spine.

Terminal uropods with outer ramus shorter than inner, and
armed apically with two hooked spines; rami less than half as
long as peduncle.

Color bright green, pale green, bluish; nearly colorless to
dark reddish brown.

Length 9 mm.

Distribution: Provincetown (Rathbun), Woods Hole, Vine-
yard Sound, New Jersey ; Noank Harbor, north of Fishers Island,
Long Island Sound.

The species is not uncommon among seaweed near shore and
in sheltered places, and has been taken at the surface in the
tow-net at Woods Hole and Noank. It is not common on eel-
grass near the roots but seems to prefer the masses of eel-grass
nearer the surface.

Professor Holmes has described the habits and natural his-
tory of the species fully in the Biological Bulletin, vol. 2, p. 165-
193, to which the reader is referred for details.

Amphithoe rubricata (Montagu).

1808. Cancer Gammarus rubricatus, Montagu, Trans. Linn.
Soc: Lond. volio;p..60, pl. 5; fig.)1:

1853. Amphithoe maculata, Stimpson, Smithson. Contrib.
Knowl., vol. 6, p. 53.

1874. Amphithoe valida, Smith, Rept. U. S. Com. Fish., * bea)
1871-2, p. 563.

Body stout, robust; interantennal lobes blunt. Eyes small,
round or oval.

150 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Fic. 44. Amphithoe rubricata.

First antenne usually more than half as long as body; first
and second peduncular joints subequal and each one twice as
long as the last one; flagellum slender and longer than peduncle.
Second antennz decidedly stout, shorter than the first in female,
relatively longer in the male; last joint of peduncle as long as pre-
ceding; flagellum short and thick, composed of few joints, and
often less than half as long as peduncle.

Coxal plate of first gnathopod produced bluntly forward;
first five deeper than their respective segments; fourth pair not
excavate behind; fifth pair with broad front lobe as deep as
preceding.

First gnathopods in the male stout, with basal joint short
and produced into a prominent lobe at antero-distal angle; pro-
podus oblong with palm oblique and convex and with posterior
angle rounded and armed with a spine. Second gnathopods with
broad basal joint with distal lobe smaller than in first pair; pro-
podus stout and provided with a tuft of sete at the apex, palm
oblique, convex toward ‘pex, concave toward prehensile angle
which is produced. In the female, first gnathopods with carpus

a ne i i

No. 26.] ARTHROSTRACA OF CONNECTICUT. I51

shorter than in male and propodus narrower, but otherwise quite
similar in form. Second gnathopods with propodus resembling
that of male but less densely setose apically, palm with a strong
prehensile spine. Third pereiopods with basal joint broader than
long.

Third segment of abdomen with postero-lateral angles
rounded.

First and second uropods spinose; first pair with peduncle
longer than rami. Third pair with peduncle twice as long as
rami; outer ramus with two strong hooks apically, inner ramus
narrower than outer, with two lateral spines and an apical one
and several sete. Telson as broad as long, apex rounded, between
two little tubercles, within which are three setules on each side.

The color of the species varies from green to reddish; gen-
erally there is a row of light colored spots along the mid-dorsal
line, one spot for each segment.

Length 20 mm.

Distribution: Norway; England; France; Azores; Labrador;

Bay of Fundy; Grand Manan; Woods Hole, Massachu-
setts; Newport, Rhode Island; Noank, New Haven (Smith),

Long Island Sound, north of Fishers Island, off Stonington, Con-
necticut.

The species occurs under rocks and in alge at low tide on
muddy shores and to depths of 9g fathoms. It occupies tubes
covered with sand and bits of alge, attached to the underside
of stones at low-water mark. >

Grubia Czerniavski. = Cymactze
Like Amphithoe but first antennz have a unitarticulate acces-
sory flagellum and second antenne an elongate flagellum. Man-
dible with third joint of slender palp not distally expanded.

\

Grubia compta (Smith). = 4

1874. Amphithoe compta, Smith, Rep. U. S. Com. Fish. for
1871-2, p. 564.

1905. Grubia compta, Holmes, Bull. U. S. Bur. Fish., vol.

24, p. 510.
Eyes round, situated on interantennal lobes.

CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

152

Gp My

AL

Lf)

N41,

SKY

Pal
/

Z , —
Se a ae

First antennz longer than second, with first and second joints
of peduncle subequal in length and twice as long as third. Flagel-
lum long and slender; accessory flagellum short, one-jointed.
Second antenne slender with elongated peduncle.

Mandibles with three-jointed palp, the distal one of which is
not enlarged distally. Lower lip with outer plates incised.
First maxille with small triangular inner plate having a number

Fic. 45. Grubia compta.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 153

of sete on inner margin and with a two-jointed club-shaped
palp. Maxillipeds with four-jointed palp and plates well
developed.

First five coxal plates large, first four oblong and first
not produced greatly anteriorly; all much deeper than their
segments ; fifth coxal plate bilobed.

Gnathopods of male- greatly elongated and provided with
abundant plumose sete, first pair as large as second; fourth joint
with posterior margin produced to form a rather slender triangu-
lar process which fits behind the very long subtriangular carpus ;
propodus oval, considerably smaller than carpus, palm oblique,
nearly straight and armed with a stout prehensile spine at the
rounded posterior angle, dactyl long and curved. Second gnath-
opods with merus and carpus smaller than in first; propodus
oblong, with a sinuous palm and posterior angle produced; dactyl
shorter and stouter than in first.

Gnathopods of female of nearly equal size and similar form,
much smaller than in male; carpus as broad as, and longer than,
propodus which is narrowed at the proximal end and expanded
distally, palm oblique and rounded posteriorly where it is armed
with a spine.

First pair of uropods with styliform rami; nearly as long as
peduncle and provided with spines on upper margin; peduncle
bearing a slightly curved prolongation distally below rami; second
uropods with rami as long as peduncle; third uropods with short,
stout rami the outer one of which is shorter than the inner and
provided distally with two strongly curved hooks; inner ramus
about one-half as long as peduncle.

Telson thick, triangular with rounded apex, provided with
several setze at distal corners.

Color variable, about as in Amphithoe longimana.

Length 12 mm.

Stebbing (1906) erroneously. refers this species to the genus
Amphithoides Kossmann from which genus Grubia differs by
having two well developed hooks on outer ramus of terminal
uropods and the terminal joint of mandibular palp not enlarged.

The species occurs generally from Cape Cod southward to
North Carolina, being especially common in eel-grass.

154 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

JASSIDZE.

Interantennal lobes often somewhat prominent. Fourth coxal
plates usually not excavate behind.

Accessory flagellum of first antenne never large, often indis-
tinct.

Third joint of mandibular palp shorter than second, laminar.

Gnathopods subchelate, second pait larger than first, often
greatly modified in the male. First and second pereiopods glandu-
lar; third pair reverted; fifth pair the longest.

Third uropods with very short rami of which the outer is
uncinate and usually surmounted by denticles. Telson simple.

Jassa Leach.

Fourth coxal plates not perceptibly emarginate behind.

Antenne setose, with flagellum shorter than elongated pedun-
cle. First antenne with first joint of peduncle shorter than
second or third; accessory flagellum very small. Second antenne
usually considerably larger than first.

Mandibles with large palp having third joint shorter than
second, distally widened, and densely setose. First maxillz with
inner plate very small and provided with marginal sete; second
joint of palp long.

Second gnathopods much larger than first, stronger in male
than female; hind margin of propodus of male produced into
a strong tooth. First and second pereiopods glandular with
basal joint slightly expanded. Posterior pereiopods with basal
joint somewhat expanded.

First and second uropods with outer ramus shorter than
inner. Third uropods with stout peduncle much longer than

rami, the outer one of which ends in a hooked spine. Telson
triangular.
Jassa marmorata Holmes.

1903. Jassa marmorata, Holmes, Amer. Naturalist, vol. 37,
p. 289.

1905. Jassa marmorata, Holmes, Bull. U. S. Bur. Fish., vol.
24 Po hkl:

Head produced into a small, broadly triangular rostrum.
Body moderately depressed. First two coxal plates as deep as

No. 26.] ARTHROSTRACA OF CONNECTICUT. 155

their segments, third pair the largest. Eyes round, situated on
the prominent interantennal lobes.

Antenne stout, their lower margins with long sete; first pair
shorter than second pair, first joint of peduncle much shorter
than second which is a little longer than the third; flagellum not
much longer than last joint of peduncle, composed of five or six
joints ; accessory flagellum minute, consisting of a single joint.
Second antennz very stout, with last joint of peduncle a little
longer than preceding one; flagellum about three-fifths as long
as last joint of peduncle.

Fic. 46. Jassa marmorata.

First gnathopods in both sexes with propodus ovate, palm
very oblique, with a row of three prehensile spines. Second
gnathopods with propodus enormously developed and produced at
proximal end of palm into a long, narrow, thumb-like process,
lower end of palm with a triangular process. In the female the
second gnathopods are much smaller than in the male, propodus
oval in outline, with front margin very convex and palm concave.
First and second pereiopods with merus much dilated and pro-
duced downwards in front.

First uropods with peduncle having a large spine on the lower
margin nearly half the length of the rami. Last pair with rami
half as long as peduncle. Telson broader than long, apex rounded

156 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

and entire and provided on either side with a minute spine and
one or two sete.

The species is conspicuously mottled. The ground color is
reddish, the spots are of a lighter color.

Length of large male 10 mm.

Distribution: Nahant, Woods Hole, Gay Head, Vineyard
Haven, Massachusetts; New Haven, Connecticut.

The species occurs frequently among hydroids and alge on
piles but has also been collected at the surface, in tide-pools and
on sandy and muddy bottoms.

I was unable to examine the specimen from New Haven
which was collected and identified by Dr. W. K. Longley.

Ischyrocerus Kroyer.

Similar to Jassa except as follows. Second coxal plates not
differently shaped from third. Second gnathopods in female a
little larger than first; in the male with hind margin of propodus
not produced into a prominent decurrent tooth.

Ischyrocerus anguipes Kroyer.

1894. Ischyrocerus anguipes, G. O. Sars, Crust. Norway,
vol. 1, p. 588, pl. 2009.

1874. Podocerus fucicola, Smith, Rep. U. S. Fish. Com.,
1871-2, p. 565.

Eyes nearly round.

First antenne considerably shorter than second, peduncle with
second joint a little longer than third and nearly twice as long
as first ; flagellum shorter than last two joints of peduncle; acces-
sory flagellum very small, consisting of an elongate joint tipped
by a very minute one. Second antenne stout and elongate;
peduncle with last two joints subequal; flagellum shorter than
last joint of peduncle and composed of five or six joints of which
the first is the longest.

First four coxal plates subquadrate, and as deep as their
respective segments.

First gnathopods in male small; basal joint broad; carpus
rounded and setose behind; propodus subovate, with palm very
oblique and nearly straight, posterior margin with a row of
spines which begins at the palm; dactyl with inner margin finely

ARTHROSTRACA OF CONNECTICUT.

SS Sa
EEN Gaia’.

157

Fic. 47. Ischyrocerus anguipes

158 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

serrate. Second gnathopods in male very large, much elongated ;
basal joint narrow, elongate, gradually widening distally and
curved forward, lower anterior angle produced downward in a
rounded lobe; ischium produced anteriorly into a prominent
rounded lobe as in first gnathopods; merus with pointed process
at infero-posterior angle; carpus triangular, with an angular
posterior projection which bears a fascicle of sete; propodus
elongate, thickened, curved backward, posterior margin some-
what concave and fringed with plumose sete and bearing a blunt
projection near distal end of segment. In the female, first gnatho-
pods quite similar to those of male but with basal joint narrower.
The second gnathopods are very much smaller than in the male
and of very different form; basal joint relatively broader and
widening more distally ; merus broadly rounded and setose behind ;
carpus subtriangular, short, produced behind into a setose lobe;
dactyl narrowly ovate with palm slightly sinuate and provided
with two prehensile spines.

First uropods with peduncle having a spine at distal end
which is much less than half as long as rami; terminal uropods
with rami very small, scarcely one-fourth as long as peduncle.
Telson triangular, with rounded apex.

In the female, besides the differences in the gnathopods, the
second antenne are much smaller than in the male, being only
a little longer and stouter than the first pair; the body is also
broader in the middle, and the second, third, and fourth coxal
plates are somewhat deeper than long.

The color varies from light olive or greenish to light crim-
son. Some specimens, according to Smith, taken at Watch Hill,
Rhode Island, “ had a transverse dorsal band of red or orange on
each segment, and similar ones on the epimera, and were minutely
speckled with dark brown; the antenne and legs were annulated
with white and light red or orange.”

Length 10 mm.

Distribution: Norway; Greenland; Labrador; Iceland;
Siberian polar seas; Grand Manan; Bay of Fundy; Marble Head
Beach, Massachusetts ; “ Prof. Smith states that ‘ this species was
dredged by Professor Verrill in 4 to 5 fathoms off Watch Hill,
Rhode Island, in April, 1873;’” Sea Flower Reef, Long

No. 26.] ARTHROSTRACA OF CONNECTICUT. 159

Island Sound, July 17, 1874; off Stonington, Connecticut, 4 to
6 fathoms, April, 1873, rocky bottom.

In the shape of the second gnathopods of the male I find
considerable variation quite similar to that described by Holmes
for Jassa marmorata. In a series of specimens collected by
Verrill off Stonington I found a number of intermediate forms
between the typical form with the hind margin of the propodus
of second gnathopod concave and the whole segment curved, to
the less usual form in which the propodus is oval and relatively
much wider than in the typical form. The series of specimens
was not extensive enough to allow of a generalization regarding
the significance of. this variation.

COROPHIIDAS.

Body usually depressed. Abdomen small. Coxal plates
usually small and often not in continuity.

Antenne of variable proportions, with or without an acces-
sory flagellum.

Gnathopods-variable in form and relative size. First and
second pereiopods usually glandular. Fifth pereiopods the
longest.

First uropods biramous; second uni- or biramous. Third
‘ pair small, weakly biramous, uniramous or without rami. Tel-
son simple, sometimes lobate.

Cerapus Say.

Body slender, abdomen depressed. Head with distinct
rostrum. First four coxal plates very small; fifth and sixth
larger.

First antenne without accessory flagellum. Flagellum of
first and second antennz short.

Mouth parts normal.

First gnathopods subchelate. Second complexly subchelate
and powerful in male, weak and simple in female. First and
second pereiopods short, glandular, front margin convex ; poste-
rior pereiopods short, recurved, with very short, bidentate finger.

Second and third uropods uniramous, with ramus short and
uncinate. Telson short, broad, bilobed.

160 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Cerapus tubularis Say.

Fig. 48. Cerapus tubularis.

1817. Cerapus tubularis, Say, Jour. Phila. Acad. Sci., vol.
I pt. 2, ps 50,epl: 4, figs. 7-11.

1880. Cerapus tubularis, Smith, Trans. Conn. Acad., vol. 4,
pp. 269-277, pl. 2, figs. 1-6.

Head with a small rostrum and a faint dorsal carina; body
greatly depressed.

Eyes small.

First and second antenne subequal in length and in male a
little over half the length of the body. First segment of first
antenne stout, laterally compressed, furnished below with a
carina which is more prominent near the base; second and third
joints subequal and each somewhat longer than first and subequal
to the flagellum which is triarticulate. Second antenne, slightly
shorter than first and with triarticulate flagellum which is nearly
as long as last joint of peduncle.

Coxal plates broader than deep; fifth pair the largest.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 161

First gnathopods with carpus produced downward at
postero-distal angle into a small lobe; propodus oblong, narrower
than carpus but about as long, palm oblique and spinose. Second
gnathopods in male with carpus having front margin convex
and furnished at its postero-distal angle with a large, acute
tooth, above which is a rounded sinus separating the latter from a
small rounded tooth; propodus oblong, slightly curved, nearly
as long as carpus, hind margin irregular; dactyl large and stout.

Second gnathopods in female similar to first pair. Third
pereiopods very small; merus with a long spatulate lobe on poste-
rior margin; carpus articulated to posterior margin of merus
above distal end of latter, and produced greatly beyond articu-
lation of oblong propodus; dactyl short and broad with an
abruptly recurved hook-like tip. Fourth pereiopods with basal
joint as long as merus, longer than broad; fifth pair more slender.

First uropods with outer ramus much larger than inner;
second pair about one-half as long as first, with a single ramus
which is very short and furnished with a terminal hook; last pair
much like preceding but stouter. Telson with two dorsal rows
of sharp, upturned spinules, about twice as broad as long and
distally emarginate.

Length 4.5 mm.

Distribution: Great Egg Harbor, New Jersey; Vineyard
Sound, Massachusetts, in masses of the compound ascidian
(Amouroucium pellucidum) ; Noank (Harbor, Connecticut ;
(Smith), Long Island Sound.

The species occurs also in eel-grass to depths of 10 fathoms.
Considerable numbers were taken at the surface in the evening
at Noank Harbor, July 21, 1874.

These animals construct thin cylindrical tubes which they
carry about with them, thus differing from the great majority of
tube-dwelling Amphipoda which inhabit a fixed tube. Professor
Smith (Trans. Conn. Acad., vol. 4, pp. 269-277) has given a full
description of the species with observations on its habits.

Ericthonius Milne-Edwards.

Body somewhat depressed, with very small coxal plates;
abdomen narrow and elongated.

11

162 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Antenne slender, subequal, peduncle long; flagellum of several
joints; no accessory flagellum; second antenne attached much
behin'd first; third joint of peduncle unusually elongated.

Mandibles short and stout with palp much elongated and
having terminal joint lamellar and densely setose. Maxillipeds
with palps comparatively narrow.

Gnathopods very unequal, the anterior ones small, with carpus
comparatively large and expanded posteriorly; propodus short
but broad. Second gnathopods in female considerably larger than

first and with carpus produced posteriorly ; propodus expanded, .

with palm well defined, in the male of enormous size and com-
plexly chelate, the carpus being extremely large and bearing
ventrally an acuminate thumb-like process; propodus narrower
than carpus and having palm imperfectly defined. Anterior
pereiopods with basal joints lamellarly expanded.

Last pair of uropods with a single lamellarly unguiform
ramus. Telson short and broad with two densely spinous pro-
cesses above.

Ericthonius rubricornis (Stimpson).

1853. Cerapus rubricornis, Stimpson, Marine Invert. Grand
Manan, Smithson. Contrib. Knowl., vol. 6, p. 43, fig. 33.

1880. Erichthonius difformis, Smith, Trans. Conn. Acad., —

vol. 4, p. 278.

Eyes nearly round. Interantennal lobes projecting strongly
forward. .

First antenne slightly longer than second, with second and
third peduncular joints subequal in length and not quite twice as
long as first joint; flagellum short. Second antenne with last
joint of peduncle a little longer than preceding one; flagellum
short and furnished with long sete on lower margin,

First gnathopods with merus produced distally to a triangular
process ; carpus large, widening distally; propodus smaller than
carpus and greatly constricted at base, two-thirds as broad as
long, palm slightly convex and finely serrated and passing gradu-
ally into posterior margin; dactyl strong, armed with a few
short spines. Second gnathopods in male very large, with carpus
produced below propodus into a large acute process; propodus
oblong, with a prominence near the distal end of posterior margin;

—- ==

No. 26. ARTHROSTRACA OF CONNECTICUT. 16
3

in female carpus produced to a lobe, which extends behind the
propodus nearly as far as the tip of the dactyl when closed,
armed near distal end with several spines and numerous sete ;
propodus ovate, palm very oblique, provided with many short
- setee and several large prehensile spines.

First and second pereiopods short and provided with spinning
glands; basal joints large, subovate, more convex in front than
behind; merus expanded and produced downwards in front;
dactyl long and slender. Last pair considerably longer than the
preceding.

Second and third uropods with margins acute and serrate;
terminal pair with a single subconical ramus which is curved and
shorter than the peduncle and has two or three short spines at
the tip.

Telson emarginate, lobes armed with numerous very short,
hook-like spines. f

Color, on the back dark mottled gray; coxal plates blackish.

Length 9 mm.

Distribution: Labrador; Grand Manan; Bay of Fundy; whole
coast of New England. It is more common north than south of
Cape Cod. Smith has reported it from Vineyard Sound.

The species inhabits flexible tubes composed of sand or mud
stuck together with a small amount of adhesive material from the
spinning glands.

It is found usually in shallow water but may extend to depths
of 100 fathoms, according to Smith.

Ericthonius brasiliensis (Dana):
1853. Pyctilus brasiliensis, Dana, U. S. Explor. Exped., vol.

12) pe. 2, -p: 676, pl: 67, fig. 5 a-h.
‘1874. Cerapus minax, Smith, Rep. U. S. Com. Fish., 1871-2,

p. 565.
1906. Ericthonius brasiliensis, Stebbing, Das Tierreich, Lief.
Zi pve ts

Eyes large, nearly round; interantennal lobes broad with a
small apical point.

Antenne of subequal length, more than one-half as long as
body. First antenne with last two joints of peduncle subequal
and about one and one-half times as long as first; flagellum as

164 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull —

long as peduncle and twelve-jointed. Second antenne with last 7

joint of peduncle a little longer than preceding one; flagellum _

nearly as long as peduncle and made up of about nine joints. 4
Coxal plates contiguous; the second and fifth being the

largest.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 165

First gnathopods short, with large carpus widening distally
and setose behind; propodus shorter than carpus, gently convex
in front, quadrately rounded behind, palm subequal to hind
margin; dactyl finely serrate. Second gnathopods in male very
large; merus very small; carpus elongated, produced beyond pro-
podus into a very large, acute process which has a very large
tooth on its front margin; propodus much narrower but not much
shorter than basal part of carpus, with a low elevation near
distal end of hind margin; dactyl with long sete apically.
Second gnathopods in female with carpus produced behind pro-
podus in a slender Icbe which is armed distally with sete and
recurved spines; propodus large, palm oblique and longer than
hind margin.

First uropods projecting beyond second and third; peduncle
slender and much longer than rami; inner margin of peduncle
of second uropods with acute serrations; margins of rami of
second and third uropods acutely serrate, the serrations on inner
rami being the larger; third uropods with peduncle broad at
base and much longer than ramus which ends in two upturned
spines.

Telson twice as broad as long, emarginate, with lobes armed
with numerous, very short, hook-like spines.

Length 6 mm.

Distribution; Europe, from Norway to the Adriatic; Rio
Janeiro; Bermuda; Vineyard Sound; Woods Hole, Massachu-
setts; Great Ege Harbor, New Jersey; Long Island Sound; New
Haven (Smith), Noank, Connecticut, off Sea Flower Reef.

The species occupies tubes which are affixed to hydroids and
algze ; it is more common according to the Woods Hole Survey at
depths between 8 and 16 fathoms.

Unciola Say.

Body slender, depressed, with small angular, coxal plates.

First antennz longer than second with an accessory flagellum.
Second antenne larger in male than female; flagellum multi-
articulate.

Mandibular palps well developed, triarticulate. Maxillipeds
with outer plates short and broad and armed inside with strong
flattened spines.

166 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

First pair of gnathopods much stronger than the second ;
propodus large and broad, subchelate. Pereiopods comparatively
slender. Three posterior pairs having basal joint expanded.

Last pair of uropods very small with peduncle expanded
medially. Telson comparatively large, lamellar, rounded.

Unciola irrorata Say.

Fic. 50. Unciola irrorata.

1818. Unciola irrorata, Say, Jour. Acad. Nat. Sci. Phila.,
vole 1, -pt.-2)-p.380: ;

1874. Unciola irrorata, Smith, Rep. U. S. Com. Fish,
1871-2, p. 567, pl. 4, fig. 19. |

Body depressed; coxal plates very low; eyes nearly round.

First antennz over half as long as body, with principal flagel-
lum shorter than peduncle; accessory flagellum shorter than last
joint of peduncle. Second antennz shorter than the first, with a
short flagellum and a strong peduncle which is very stout in the
male.

First gnathopods much stronger than second and of similar
form in the two sexes; basal joint thick and hollowed out in
front; carpus short; propodus very large and oval, with convex

No. 26.] ARTHROSTRACA OF CONNECTICUT. 167

palm provided with many spines and finely serrated and marked
off from the short posterior margin by a stout triangular process ;
armed apically with a spine; dactyl strong and curved. Second
gnathopods slender; carpus triangular and as wide as, but shorter
than, propodus, and abundantly provided with sete; propodus
oblong, tapering very slightly to distal end, also provided with
dense sete on the margins, palm short, transverse, infero-posterior
angle of propodus slightly produced; dactyl very small. Last
pair of pereiopods much longer than others, with a long slender
dactyl.

Third abdominal segment with postero-lateral angle produced
into a slender curved point above which is a prominent sinus.

First uropods with peduncle having an upturned spiniform
projection beneath the rami which are one-half as long as
peduncle; second pair with no spiniform, projection; last pair with
a single ramus not half as long as peduncle but with peduncle pro-
duced into a lobe as large as ramus and lying internal to the
ramus. Telson rounded, slightly longer than broad, not extending
back quite as far as terminal uropods.

In life the body is mottled bright crimson, head with a broad
median band of crimson which divides in front. The first
thoracic segment is more highly colored than the others; a row
of small crimson spots along either side of the mid-dorsal line;
bases of both pairs of antennz crowned with orange; flagellum
with a double row of crimson spots, a pair to each segment, pro-
podus of first gnathopods with crimson blotches.

Length 15 mm.

Distribution: Great Egg Harbor, New Jersey ; from Connecti-
cut to the Bay of Fundy (Smith); Nova Scotia; Labrador;
Greenland; Spitzbergen; Norway; off New London, Connecti-
cut, taken at 8 fathoms on sandy bottom, July 17, 1874; off Say-
brook; Fishers Island Sound; north of Fishers Island; 3% to 5
fathoms, Aug. 10, 1874.

The species ranges in depth from low-water eet to 500
fathoms. It is an exceedingly abundant species, occurring more
abundantly on muddy or sandy bottoms.

According to Smith (Trans. Conn. Acad., vol. 4, p. 282) these
animals do not construct tubes for themselves but are often
found in the tubes of other Amphipoda and Annelida.

168 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Siphoneecetes Kroyer.

Body slender and narrow, abdomen very small. Coxal plates
very small.

Antenne densely setose and unequal; first pair slender and
without accessory flagellum; principal flagellum well developed.
Second pair much longer than first, subpediform, with short
flagellum armed apically with unguiform spines.

Mandibular palp small, uniarticulate.

Gnathopods unequal, the second pair being considerably
stronger than the first pair and distinctly subchelate. Anterior
pairs of pereiopods with basal joint and merus much expanded ;
third and fourth pereiopods comparatively small, with dactyl
inverted; last pair considerably more elongated and with basal
joint lamellarly expanded and fringed on both sides with ciliated
sete. *

First and second uropods biramous, with outer ramus the

larger and spinulous externally. Last pair with peduncle lami-

narly expanded; single ramus small, simple, setiferous.
Telson imperfectly defined from last segment, smooth above
and broadly rounded at tip.

Siphoneecetes smithianus Rathbun.

1874. Stphonecetes cuspidatus, Smith, Rep. U. S. Com.
Fish., 1871-2, p. 566.

1905. Siphonecetes snuthianus, Rathbun, Occas. Papers,
Boston Soc. Nat. Hist., vol. 7, p. 74.

Head produced into a long, slender, acute rostrum, inter-
antennal lobes long, projecting in a rounded form at the end
and somewhat constricted at the base. Eyes situated on inter-
antennal lobes.

First antenne of female extending as far as penultimate
joint of peduncle of second antenne; first joint of peduncle
stouter than succeeding ones, but subequal in length to each
of them; flagellum of about four joints and one-half as long as
peduncle. Second antennz two-thirds as long as body; peduncle
stout, third joint as long as first joint of peduncle of first antenne,
fourth joint longer than fifth which in turn is nearly one-half
longer than the third; flagellum slightly longer than third joint,

No. 26.] ARTHROSTRACA OF CONNECTICUT. 169

composed of only two joints of which the terminal one is minute.
In the male the second antenne are a little longer than the body
and stouter than in the female.

Fic. 51. Siphonecetes smithtanus.

Coxal plates low and not contiguous, with sete on ventral
and anterior margins.

First gnathopods in female with carpus as long as, but broader
than, propodus, with slightly convex front margin, which bears
six fascicles of sete; propodus tapering, simple, hind margin

170 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

with abundant stout sete; dactyl with several serrations near
tip on inner margin. Second gnathopods with basal joint very
stout; merus elongated on posterior margin and terminating in a
rounded apex which bears long sete ; carpus with a rounded lobe
behind; propodus oblong oval, twice as long as wide, with
numerous fascicles of sete on front margin, palm long, armed
with sete and four spines near the poorly defined prehensile
angle; dactyl with inner margin serrated. First two pairs of
pereiopods with basal joints greatly expanded and front and hina
margins strongly convex; merus subcordate in form, with front
and hind margins setose; carpus very short; propodus tapering,
about twice as long as wide; dactyl straight, slender, and nearly
as long as the two preceding joints together. Third and fourth
pereiopods with basal joints stout but not greatly expanded; car-
pus as broad as long; propodus somewhat curved backward;
dactyl stout and strongly curved. Last pair elongated; with
oval basal joint provided on front and hind margins with abun-
dant long setz.

First pair of uropods extending beyond the others; peduncle
cylindrical and twice as long as outer ramus which is much
larger than inner; distal end of peduncle internally finely ser-
rated for a short distance; outer ramus with stout spines on
. outer margin and a long one apically. Second pair with outer
ramus longer than inner but not as long as peduncle. Terminal
uropods with a single ramus less than one-half as long as
peduncle which is expanded to a rounded lobe distally and
medially which bears several sete apically; ramus as broad as
long and with several long sete at the rounded tip. Telson
broader than long, transversely elliptical.

Length 6 mm.

Distribution : in deep water off Vineyard Sound and Buzzards
Bay ; Long Island Sound.

The species inhabits tubes constructed of grains of sand,
usually on bottoms of fine compact mud and sand.

Corophium Latreille.

Body comparatively stout and much depressed, with extremely
small coxal plates; first pair conically produced and tipped by a

No. 26.] ARTHROSTRACA OF CONNECTICUT. . 171

number of strong ciliated sete. Posterior segments of abdomen
flattened and sometimes fused.

Antenne unequal; first pair slender, without accessory flagel-
lum but with principal one multiarticulate. Second antennz
strong, pediform, generally much stronger in male than female;
fourth joint of peduncle large and produced distally to a spini-
form process; flagellum short, triarticulate, terminating in several
small hooks.

Mandibles with palp small and narrow, composed of only
two joints. First maxillze with inner plate obsolete. Second
maxillze with outer lobe larger than inner. Maxillipeds with
inner plates narrowly produced; outer plates long and narrow;
palp slender, with fourth joint short and setose at tip.

First gnathopods slender with ischium forming below a
rounded, densely setose expansion, carpus much elongated and
densely setose behind, propodus narrow, with short palm. Second
gnathopods somewhat stronger than first; merus forming a broad
lamellar expansion which is firmly connected with posterior
margin of carpus, and edged with a double row of extremely
elongated and finely ciliated setee; propodus sublinear, without
distinct palm. First two pairs of pereiopods with basal joint
large and broad and merus more or less expanded. The two
succeeding pairs comparatively stout and of same structure, both
having merus obliquely expanded in front and carpus armed
with two oblique rows of strong spines. Last pair of pereiopods
elongated and slender with basal joint expanded and densely
fringed with long ciliated setee on both margins.

First and second uropods with short rami; last pair with
peduncle scarcely expanded, and single ramus lamellar and
setose. Telson small, entire.

Corophium cylindricum (Say).

1818. Podocerus cylindricus, Say, Jour. Acad. Nat. Sct.
Philagevol. 17 pt! 2, p.387.

1874. Corophium cylindricum, Smith, Rep. U. S. Com. Fish.,
1871-2, p. 566.

Body broad and much depressed, with very small coxal
plates which are discontinuous. Fourth, fifth, and sixth abdom-
inal segments fused.

172 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Fic. 52. Corophium cylindricum.

Antenne stout in female, first pair nearly as long as second
pair, less than one-third as long as body. First antennz with first
joint of peduncle very stout and slightly longer than second, pro-
vided with several stout spines on lower margin, third joint one-
half as long as second; flagellum as long as second and third
joints of peduncle together, and made up of about six rather long
segments. Second antenne very stout, pediform, especially in
the male; second and third joints only slightly longer than broad,
third joint with four stout spines distally, fourth and fifth joints
subequal in length in the female and each about as long as first
two joints together, and provided with a few stout spines. In
male the lower margin of penultimate joint is produced distally
to form a curved, finger-like process. Flagellum very short and
stout and made up of three joints terminating in two curved
spines.

First gnathopods with coxal plate produced anteriorly and
tipped with three sete; carpus rectangular and slightly longer
than propodus, with hind margin provided with long plumose
spines; propodus widening a little distally, subchelate, palm

No. 26.] ARTHROSTRACA OF CONNECTICUT. 173

slightly oblique. Second gnathopods with simple propodus;
posterior margin of merus and carpus provided with very long
plumose spines; basal joint exceedingly stout; merus with hind
margin strongly convex ; carpus short and articulating with front
margin of merus; propodus subrectangular and slender; dactyl
strong and with denticle on inner margin. First and second perei-
opods with very long dactyl and stout propodus; carpus short and
merus projecting anteriorly and distally as a moderate lobe.
Third and fourth pereiopods short; carpus short and armed
distally with stout spines; basal joint of fourth pair with a few
setee on the posterior margin. Fifth pair of pereiopods very
long and slender with basal joint oval and with margins setose.

First uropods with rami half as long as peduncle; second pair
not projecting as far as first pair, with rami nearly as long as
peduncle and with apices rounded. Terminal pair, uniramous,
peduncle very short and ramus broadly ovate, extending about as
far posteriorly as second pair. Telson very short and thick,
triangular, entire.

The body is marked with purplish brown pigment cells and
the posterior margin of each segment bears a dark transverse
band. The anterior part of the head is dark.

Length 3 mm.

Distribution: New Jersey to Vineyard Sound. Noank
Harbor, taken at the surface in the evening, also found on piles
and among sponges growing on piles; Noank, Long Island Sound,
Sea Flower Reef, New Haven, Connecticut.

The species lives in soft tubes although it is often found free.
The tubes are particularly common in eel-grass near the roots.
It is very common at all depths to 30 fathoms. In dredging,
according to the Woods Hole Survey it is rarely found on muddy
bottoms.

CHE LURIDA:

Fourth to sixth abdominal segments coalesced. Coxal plates
small.

Second antenne with blade-like flagellum.

Pleopods with peduncle produced on inner side.

Second and third uropods abnormal.

174 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Chelura terebrans Philippi.

1839. Chelura terebrans, Philippi, Arch. f. Naturgeschichte,
vol. 5, p. 120, pl. 3, fig. 5. :

1879. Chelura terebrans, S. 1. Smith, Proc. U. 5. Nat. Mus.,
vol. 2, p. 232.

1894. Chelura terebrans, G, O. Sars, Crust. Norway, vol. 1,
p. 627, pl. 225.

This species of wood-boring Amphipod is not widely dis-
tributed on the Atlantic coast of North America, having been
reported only from Woods Hole and Provincetown, Massachu-
setts. It occurs along the coast of Europe from Norway to the
Mediterranean and also at Bermuda.

It is readily distinguished from all other crustaceans by the
structure of the uropods; the first pair lie under the abdomen
and have a long peduncle and two short rami. The second pair
have the dorsal edge of the peduncle expanded into a thin, broad,
oval plate projecting beyond the two small rami which are
attached in an emargination of the lower margin. The last pair
have very stout but short peduncles to each of which is attached
a single very long, strong ramus which is much longer in the
males than females.

Length 6 mm.

CAPRELET DEA

Head fused with first thoracic segment, first gnathopods situ-
ated close to mouth parts; body slender and filiform; maxillipeds
with well developed palp, one to four-jointed ; coxal plates want-
ing; gills present usually only on two segments; anterior pereio-
pods rudimentary or wanting; abdominal appendages lacking or
rudimentary. Hepato-pancreatic tubes, two ; rectal gland lacking;
heart with three pairs of ostia.

fEginella Boeck.

Body slender, sometimes smooth, sometimes coarsely spinous.

Antenne slender and elongated; second antennz with short,
biarticulate flagellum.

Mandibles with molar tubercles well marked and palps moder-
ately developed and triarticulate. Maxillipeds with outer plates
strongly spinous on inner margin.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 175

Gnathopods .very unequally developed, the first pair being
small. Second pair much elongated with propodus exceedingly
large and with palm divided into acute lappets. First two pairs
of pereiopods wholly absent. Three posterior pairs strongly
developed and similar, with propodus large and expanded at
base. Gills present on only the third and fourth thoracic seg-
ments.

Abdomen with two pairs of appendages in both sexes.

Le
|

ZEginella longicornis (Kroyer).

Fic. 53. Aginella longicornis.

1842-3. AZgina longicornis Kroyer, Naturhist. Tidsskrift,
1 Rakkes, 4 Bind.

Body slender, smooth or spiniferous, head often furnished
with a pair of dorsal spines.

Eyes small.

176 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull

First antenne long, with last joint of peduncle nearly as long
as preceding one; flagellum shorter than peduncle. Second
antenne extending but little beyond penultimate joint of peduncle
of first; last joint of peduncle longer than the preceding one;
flagellum biarticulate and shorter than last joint of peduncle.

First gnathopods with propodus having palm nearly straight
and extending to proximal end of joint where it is defined by a
stout prehensile spine. Second gnathopods with basal joint
usually slightly dentate in front and produced below into an
acute lobe; ischium and merus each with an acute inferior
process; propodus with a triangular tooth at upper end of palm
and a narrow tooth below the middle separated from a triangular
eminence below by a narrow sinus.

Third, fourth, and fifth pereiopods increasing in size poste-
riorly.

Gills oval, elongated.

Abdomen with two pairs of appendages in both sexes; the
first pair of which are biarticulate.

Length 16 mm.

Distribution: Siberia; Greenland; Labrador; Eastport,
Maine; Narragansett Bay; Woods Hole, Massachusetts; Long
Island Sound; off Sea Flower Reef.

The development of spines on the body is very variable; they
may be reduced to small tubercles or entirely absent.

Caprella Lamarck.

Body more or less slender, being as a rule much more
elongated in the male than female.

First antenne elongated. Second antenne generally densely
setose below, flagellum biarticulate.

Mandibles without palp. Maxillipeds with outer plate
scarcely larger than inner one; palp very strong.

First gnathopods of usual structure. Second pair strongly
developed. First two pairs of pereiopods entirely wanting ; three
posterior pairs of similar form, generally strongly built and sub-
chelate. Gills present only on the third and fourth thoracic
segments.

Abdomen in female without distinctly defined appendages ; in
male with a pair of biarticulate limbs in front.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 177,

Caprella linearis (Linnzus).

Cancer linearis, Linneus, Syst. Natur., p. 1056.
Body slender, although the third and fourth thoracic seg-
ments of female which bear marsupial plates are rather broad,

Fic. 54. Caprella linearis.

smooth except for a few slender tubercles on the three posterior
segments. Body of adult male much more slender than female,

12

178 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

first free thoracic segment equaling in length the three succeeding

segments combined.

Eyes small, round.

First antenne in female stout, half as long as body; first and
third joints of peduncle subequal, second joint longer; flagellum
nearly as long as peduncle and composed of about a dozen joints.
In male joints of peduncle expanded and finely ciliated on edges.
Second antennze longer than peduncle of first ; flagellum composed
of two joints and as long as last joint of peduncle.

First gnathopods with carpus short and forming a rounded
lobe bearing sete posteriorly ; propodus twice as long as carpus,
triangular, with palm occupying whole posterior margin and
defined proximally by a projecting angle armed with a spine.
Second gnathopods in female attached in front of middle of
segment; basal joint with antero-distal angle produced to form
a triangular process; propodus oval, palm defined proximally
by a prominent projection with spine and bearing a small tri-
angular lobe near distal end. In male second gnathopods with
basal joint longer than propodus and attached near posterior end
of corresponding segment; propodus long and slender, oblong in
form, palm irregularly indented, having at the middle an acute
projection, and in front of projecting angular lobe, the two being
separated by a deep sinus.

Gills large and oval.

Pereiopods three pairs, stout; with narrow propodus having
palm about two-thirds as long as posterior margin and defined
proximally by a projection bearing a spine.

Length 16 mm. Females always much shorter than males.

Distribution: European coast south to France; Greenland and
Labrador (Ortmann); Casco Bay, Maine; Portsmouth, New
Hampshire (Mayer) ; Grand Manan (Holmes) ; off Head Harbor
to Salem, Massachusetts; Annisquam; off Montauk Point
(Holmes) ; Noank, Connecticut.

Caprella geometrica Say.
1818. Caprella geometrica, Say, Jour. Acad. Nat. Sci. Phila.,
vol, 1, pt: 2,.p: 300.
Body robust and devoid of spines and tubercles; head with
large triangular process projecting anteriorly.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 179

Fic. 55. Caprella geometrica.

Antenne stout, first pair with second joint of peduncle the
longest, and with flagellum, composed of about a dozen segments
and shorter than peduncle. Second antennz two-thirds as long

180 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

as first with ventral margin of peduncle fringed with long sete,
fifth joint of peduncle the longest; flagellum as long as penulti-
mate joint of peduncle and composed of two segments.

First gnathopods with very short basal joint; carpus bearing
a rounded lobe posteriorly which is provided with group of long
sete; propodus triangular, twice as long as wide, with anterior
and posterior margins slightly convex, palm coincident with
posterior margin and finely serrated, proximal angle with stout
spine ; dactyl long and stout with concave margin serrated.

Second gnathopods with basal joint shorter than propodus
and bearing a rounded lobe at antero-distal angle; carpus very
short; propodus oval, tapering somewhat distally; setose. palm
convex and nearly as long as posterior margin and demarcated
by a process and two spines, anterior margin strongly convex,
pereiopods stout; carpus as broad as long and one-third as long
as propodus which has a palm nearly as long as front margin,
demarcated from it by a prominent projection having a spine
on its apex; dactyl long and strongly curved.

The color is very variable. Some individuals are nearly color-
less; others are uniformly reddish; and others mottled.

Length, of adult male, 15 mm.

This is one of the commonest species of Amphipoda on the
coast of New England. North of Cape Cod it is more rare, and,
according to Holmes, it has not been found at all as far north
as Maine; southwards it probably extends beyond Virginia.
Within the limits of Connecticut it has been obtained at New
Haven and Noank; at the latter place in eel-grass and on the
piles of a wharf, in sponges, etc. The species has also been re-
ported from the Mediterranean, Belgium, France, Great Britain,
Hong Kong, and Rio Janeiro.

Caprella zquilibra Say.

1818. Caprella equilibra, Say, Jour. Acad. Nat. Sci. Phila.,
vol. "lL pt: p:

Body comparatively robust and perfectly smooth above, with
anterior part very much elongated. Head without an anteriorly
directed spine.

Second gnathopods of the male with the basal joint very
much shorter than the propodus and attached near the posterior

No. 26.] ARTHROSTRACA OF CONNECTICUT. 181

end of the segment. A ventral spine between the bases of the
second gnathopods.

Length of adult male 13 mm.

This species has a remarkably wide distribution. It has
been recorded from the British Isles, France, the Mediterranean,
Azores, Bermuda, Brazil, Japan, New South Wales, New Zealand,
and the whole Atlantic coast of North America.

PART II

ISOPODA

183

No. 26.] ARTHROSTRACA OF CONNECTICUT. 185

PART II. ISOPODA.

The Isopoda are divided into six suborders by Sars, whose
classification of the group is usually followed and upon whose
key the following one is based.

KEBY=TO THE SUBORDERS OF ISOPODA.

A. First gnathopods chelate; uropods terminal; pleopods when dis-
tinctly developed, exclusively natatory ........ TANAIOIDEA p. 193
AA. First gnathopods not chelate.
B. Uropods lateral.
C. Uropods forming together with the terminal segment of the
abdomen a caudal fan; pleopods for the most part natatory
CYMOTHOIDEA p. 197
CC. Uropods valve-like, inflexed, arching over the pleopods
which to a great extent are branchial ...... IDOTHEOIDEA p.214
BB. Uropods terminal.
C. Pleopods exclusively branchial, generally covered by a thin
opercular plate (the modified first pair) ....ASELLOIDEA p. 230

CC. Pleopods fitted for air-breathing ........ ONISCOIDEA pp. 237
CCC. Pleopods, when present, exclusively branchial in the adult

and not covered by an operculum ........ BOPYROIDEA p. 235

EXTERNAL ANATOMY.

The Isopoda differ most strikingly from the Amphipoda in
the general form of the body which is always depressed or, at
least, not compressed laterally. The Anthuridz are very slender
and elongate and represent an extreme condition which is com-
parable with that of the Caprellidea. With-the exception of the
Bopyride, which are parasitic, the Isopoda are all bilaterally
symmetrical. In this one aberrant family the males and females
are exceedingly different in form, the females being four or five
times larger than the males and exhibiting marked degenerative
changes while the males are minute and remain permanently
attached to the body of the female in the region of the latter’s
genital openings.

The segmentation of the body is less regular than among the
Amphipoda; the head is fused with the first thoracic segment in
the Tanaioidea and the segments of the abdomen suffer various

186 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

degrees of reduction. Many of the Sphzromide and Oniscoidea
such as Oniscus asellus and Armadillidium vulgare are capable
of rolling the body completely into a ball.

The head may be regarded as composed of seven coalesced
segments as in the Amphipoda, the segments being indicated by
the appendages.

The eyes, which are always present in New England species,
are paired ; they may be small and simple, or large and compound,
made up of many ocelli. In the Tanaide the eyes are situated
on stalks which are never movable, but in all other families the
eyes are sessile.

There are always two pairs of antennz as in the Amphipoda,
but their relation to each other is somewhat different; for the
first pair, instead of arising dorsal to the second, arise nearer
the middle line and so may be designated as the inner antenne.
In the Oniscoidea the first pair are very small and inconspicuous
and are never more than three-jointed. Usually besides the three
joints of the peduncle there is a multiarticulate flagellum. In the
Idotheoidea the flagellum is uniarticulate, the segments evidently
being fused. In the Tanaide the flagellum of the first antenne is
rudimentary or wanting in the females, as is also the case in the
female of Cyathura.

The second antennz are usually composed of a peduncle of
five joints and a multiarticulate flagellum, but in Erichsonella
the flagellar joints are all fused to a single elongate tapering
joint. The flagellum is rudimentary in both sexes of the Tanaide,
and in the genera Edotea and Cyathura.

The mouth parts of the Isopoda resemble closely those of the
Amphipoda although there are a few important distinctive
characters, as for instance; in the Isopoda the first maxille are
generally devoid of a palp while the second pair carry external
to the outer plate a lamellar appendage which is to be looked upon
as a palp; and the maxillipeds regularly have a single pair of
plates homologous with the inner plates of those of the Amphip-
oda, and external to the proximal segment there is an epipod or
epignath which is entirely lacking in that group.

The mandibles usually bear a three-jointed palp but in the
Tanaide, Oniscoidea, and Idotheidz the palp is entirely lacking.
The molar tubercle is wanting in the Cymothoide, Limnoriide,
Armadillidide, Oniscide, and A®gide.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 187

The first maxille lack a palp in all the Isopoda except the
Tanaioidea in which a backwardly directed one is present. The
Tanaide and A*gide exhibit a single lobe in the first maxillz
whereas typically the first maxilla consist of two unequal lobes,
the inner of which is the smaller. The second maxille are typi-
cally tri-lobed at the apex but in the Oniscoidea they are laminar
with only a slight indication of division into lobes; in the AXgidz
there are only two lobes and in the Tanaidz the second maxillze
are quite rudimentary,

The maxillipeds bear a palp of a varying number of joints
and have a single expansion corresponding to the inner plates of
the Amphipoda. In the Tanaoidea the epipod extends within the
branchial cavity beneath the lateral margins of the carapace and
serves as a bailer like the scaphognathite of the Decapoda. In
the A°gide the epipod becomes fused with the basal joint.

In the Anthuridz the mouth parts are suctorial rather than
masticatory in function.

The thorax is always distinctly segmented, and in the New
England forms, with the exception of the Tanaioidea, is made
up of seven free joints. In the single group mentioned the first
segment is fused with the head.

The legs are normally fourteen in number, and made up of the
same number of joints as in the Amphipoda. The most important
distinction from the legs of the latter group is in the coxal plates
which are usually not separated from their respective segments
and are never as movable as in the Amphipoda. In no case is the
first coxal plate separated from its segment. In the Tanaide
the coxal plates, or epimera, are quite small, while in the Onis-
coidea they are greatly expanded.

It is only in the Oniscoidea that the legs are sufficiently
similar in structure to warrant the name of the whole group —
Isopoda. The first pair are frequently quite different from the
succeeding ones. In the Tanaide the first pair are chelate, and
in many of the other groups the first one or two pairs are sub-
chelate.

In the females odstegites are attached to four pairs of append-
ages, generally to the first four but occasionally to appendages
two to five inclusive. The Cymothoide are exceptions, bearing
five pairs of odstegites on the first five pairs of appendages and

188 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

also two pairs of small supplementary ones on the succeeding
segments. In the genus Tanais the odstegites are limited to a
single pair borne on the fifth segment.

The abdomen consists typically of six segments, as is clearly
indicated by the appendages; the five anterior segments are
short, the terminal one is large. The abdominal segments suffer
various reductions in number by fusion with each other. Thus
in the Aselloidea, and the genera Erichsonella, Jera, and Edotea
all the segments are united to a single large plate; in the Spero-
midee and females of Cyathura the five anterior abdominal seg-
ments are fused together; in /dothea the abdomen consists of
two short segments and a large terminal one; in Chiridotea, of
three short ones and a large terminal one; and in Tanais, of four
short ones and a large terminal one.

The appendages of the abdomen consist of pleopods and uro-
pods, but unlike the Amphipoda there is never more than one pair
of uropods, which are terminal in position in the Tanaioidea, the
Oniscoidea, and Aselloidea, and lateral in the Cymothoidea and
Idotheoidea. In the Tanaioidea the uropods are composed of
many joints but in the Oniscoidea and Aselloidea the rami are not
jointed but styliform. In the Cymothoidea the uropods are more
or less lamellar in form, consisting of a peduncle and two oval
rami, and with the terminal segment of the abdomen, with which
they articulate laterally, form a kind of caudal fan somewhat
like that of the Macrura. In the Anthuride the outer ramus
occupies a superior position arching over the telson, and in the
Spheromide the inner ramus is fixed and only the outer one is
movable. In the Idotheoidea the uropods close over the pleopods,
meeting ventrally in the middle line like double doors. These:
valves articulate with the terminal segment of the abdomen only
along the lateral margin.

The pleopods are usually present in five pairs and consist of
a peduncle and two lamellar rami. They function for swimming
and respiration; and in the male the inner ramus of the second
pair bears a slender stylet which aids in copulation. In the
Cymothoidea the pleopods are both natatory and respiratory ;
in the Aselloidea and Idotheoidea they are respiratory exclusively ;
and in the Tanaioidea they are exclusively natatory, respiration
in this group being accomplished by means of special chambers |

No. 26.] ARTHROSTRACA OF CONNECTICUT. 189

under the sides of the posterior part of the carapace. In the
Oniscoidea air sacs, or trachez, adapted for air breathing, are
developed in some or all of the pleopods. In Tanais the pleopods
are reduced to three pairs; and in the Asellidz the first pair of
pleopods is quite small and the outer rami of the second pair are
very large, forming a kind of operculum in the female, and com-
plex copulatory organs in the male. In the Oniscide and
Armadillidide the first and second pairs of pleopods are modified
to form sexual organs in the males, those of the first pair often
being coalesced in the Oniscidz and rudimentary in the females.

INTERNAL ANATOMY.

The alimentary canal is a straight tube much as in the
Amphipoda. A ccecal appendage corresponding to the rectal
gland is lacking. From the union of the stomach and the intestine
there extend posteriorly four hepatic coeca which are more or
less coiled.

The heart is an elongated tube situated to a great extent in
the abdomen except in the Tanaioidea, where it occupies the
anterior part ot the thorax, and in the Asellide, where it is con-
fined to the thorax. The dorsal aorta arises from the anterior end
-and in the method of branching there is great variation in different
species.

The nervous system and reproductive organs in general are
similar to those of the Amphipoda.

BIOLOGY.

Like the Amphipoda this group is for the most part marine,
but unlike that group there are some forms among the Oniscoidea
which have extended their habitat to land and are fully adapted
to a terrestrial form of life by the modification of the pleopods.
Within New England there is but a single fresh-water form —
Asellus communis — which is widely distributed and very abun-
dant. The terrestrial forms include several of practically world-
wide occurrence such as Armadillidium vulgare, Porcellio scaber,
Oniscus asellus, Metoponorthus pruinosus.

Of the European forms which are found on the Atlantic coast
of North America are Jdothea metallica, Cyathura carinata, 4iga
psora, Cirolana concharum, Idothea marina, Jera marina, Lepto-
chelia savignyt, Tanais cavolinii, Linnoria lignorum.

190 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

The food of the Isopoda consists for the most part of mol-
luscs, annelids, crustacea, and fish which are consumed generally
when dead. Cirolana concharum feeds on the blue crab, from a_
single specimen of which as many as 108 individuals have been
taken. The stomachs of terrestrial forms have been found to
contain moss cells and alge.

Besides the Bopyrids there are several other forms which are
also parasitic. The Cymothoidz and A‘gide attach themselves to
the fins, gills, and mouths of fishes. A‘gathoa oculata has been
taken from the mouth of a squid and also from a young mullet.
The Bopyride are all parasitic on Crustacea and attach them-
selves to the abdomen or within the branchial cavity beneath the
carapace.

The secondary sexual differences which occur among the
native Isopoda are less marked than among the Amphipoda. In
the Tanaide the legs of the first pair in the males are much more
robust and longer than those of the females but of similar form.
In Leptochelia the males have greatly elongated first gnathopods
and antennz while the females have these parts much reduced.

The development of several genera, Jera, Asellus, Ligia,
Cymothoa, Porcellio, and Armadillidium has been described fully
by McMurrich, 1895 (Journal Morphology, vol. 11, pp. 63-155).

PISTIOF SRECIESe

In the following list of Isopoda, an * before a species indicates
that it has not been reported from Connecticut although it has
been reported from adjacent regions and may be expected in this
state as well; a + indicates that the species occurs in fresh water;
and a { that the species is terrestrial.

TANAIOIDEA Of CHELIFERA, Edotea triloba (Say).

; _ Tanaide E. montosa (Stimpson).
Tanais cavolinn Milne-Edwards. Erichsonella attenuata (Harger).
Leptochelia savignyi (Kroyer). E. filiformis (Say).

*L. rapax Harger.

1 Since the manuscript of this paper was completed Professer A. E. Verrill has informed
me of two species of Isopoda which have not hitherto been recorded from Connecticut, but
which he had collected during the past two years at the Thimble Islands. These two spe-
cies I believe will be figured by Professor Verrill in his forthcoming report on the Higher
Crustacea of Connecticut, to be published in this series. The twospecies are Olencira pre-

gustator, parasitic on the mouth and gills of menhaden, and Jone thompsont,, parasitic on
the gills of Callianassa stimpsoni,

No. 26.] ARTHROSTRACA OF CONNECTICUT. IQI

CYMOTHOIDEA Of FLABELLIFERA. ASELLOIDEA Or ASELLOTA,

Anthuride. Asellidz.
Cyathura carinata (Kréyer). tAsellus communis Say.
Ptilanthura tenwis Harger. Janiride.
Cirolanide. Jera marina (Fabricius).
Cirolana concharum (Stimpson). BOPYROIDEA Or EPICARIDEA.
AE gide. Bopyride.
4iga psora (Linn). *Stegophryxus hyptius Thompson.
Cymothoide. *Probopyrus pandalicola (Packard).
Zé gathoa oculata (Say). . ONISCOIDEA.
Livoneca ovalis (Say). Oniscide.
Limnoriide. tOniscus asellus Linn.
Limnoria lignorum (Rathke). Philoscia vittata Say.
Spheromide. tCylisticus convexus (DeGeer).
Spheroma quadridentatum Say. tPorcellio rathkei Brandt.
IDOTHEOIDEA Of VALVIFERA. <P. spinicornis Say.
Idotheide. =P. scaber Latreille.
Chiridotea ceca (Say). t{Metoponorthus pruinosus (Brandt).
C. tuftsii (Stimpson). Actoniscus ellipticus Harger.
*Idothea metallica Bosc. Armadillidide.
I. baltica (Pallas). tArmadillidium vulgare (Latreille).
I. phosphorea Harger. Scyphacide.

*Scyphacella arenicola Smith.

KEY TO THE GENERA OF ISOPODA.
A. First pair of legs chelate, uropods terminal.
B. Uropods simple, short, uniramous, pleopods three pairs
Tanais p. 103
BB. Uropods biramous, pleopods five pairs ..... Leptochelia p. 195
AA. First pair of legs not chelate.
B. Uropods lateral.
C. Outer ramus of uropods arching over base of telson.
D. Maxillipéds with uniarticulate palp ...... Ptilanthura p. 200
DD. Maxillipeds with biarticulate palp ........ Cyathura p. 108
CC. Outer ramus of uropods not arching over base of tel-
son, and uropods not inflexed ventrally.
D. Abdomen of six segments.
E. Uropods with one ramus rudimentary ...Limnoria p. 211
EE. Uropods with both rami well developed.
F. Maxillipeds with palp free and margins of last two
joints never furnished with hooks ...Cirolana p. 203
FF. Maxillipeds with palp embracing distal portion of

buccal mass.
G. Both pairs of antennz with peduncle and flagellum

Wiel larcletrtnedia rere ciate stetets cleksnc) tyetersreyosepatel ences fEga p. 205
GG. Antenne much reduced, without clear distinction
between peduncle and flagellum.
H. Head produced posteriorly in three lobes, a
larger median one and two small lateral

Gis: Eee be coc OC RO oe pear ZEgathoa p. 207
HH. Head not produced posteriorly..Livoneca p. 209
DD Ahdoment ote two, SCGtmienmts) js). ais Sphzroma p. 212

CCC. Uropods inflexed ventrally and valve-like.

192 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

D. Sides of head emarginate and produced laterally beyond

the eyes, which are dorsal ...........--. Chiridotea p 215
DD. Sides of head not produced laterally; eyes placed
laterally.

E. Flagellum of second antenne multiarticulate.
Idothea p. 218
EE. Flagellum of second antenne not multiarticulate.
F. Second pair of antenne shorter than first..Edotea p. 223
FF. Second pair of antenne longer than first
: Erichsonella p. 227
BB. Uropods terminal.
C. Pleopods exclusively branchial.

D. Fresh-water. First pleopods in male not coupled with
second pair, peduncle short; second pair small and
Situated. DeloweiESt Pall) gs ele, eeiiaae Asellus p. 231

DD. Marine. First pleopods in male coupled with second
pair, peduncle elongate; second pair large and situated
externalto; first: S.2.053/: ocilek 2 cee ee eee Jezra p. 233

CC. Pleopods fitted for air-breathing.

D. Second antennz long and close together; legs long; uro-
pods produced, reaching beyond terminal segment of
abdomen.

E. Flagellum of second antennz of three joints.

F. Epimera of thoracic segments large, with posterior
angles acute; abdomen not abruptly narrower

than thorax ns costa eee Geneon Oniscus p. 238
FF. Epimera of thoracic segments small; abdomen ab-
ruptly narrower than thorax ....... Philoscia p. 240

EE. Flagellum of second antenne of two joints.
F, Abdomen not abruptly narrower than thorax; epi-
mera of abdominal segments large.
G. Body very convex, capable of rolling up like a ball;
joints of flagellum of second antenne _ sub-
EQUAL A the... SEE ee Ee Cylisticus p. 241
GG. Body more depressed, scarcely contractile;
first joint of flagellum of second antennze
longer. than seconds j.4: eee eee Porcellio p. 243
FF, Abdomen abruptly narrower than thorax; epimera
of abdominal segments small..Metoponorthus p. 247
EEE. Flagellum of second antennz of four joints.
Actoniscus p. 249
DD. Second antenne generally short. Contractile into
ball; head deeply immersed in first thoracic segment.
Armadillidium p. 251

No. 26.] ARTHROSTRACA OF CONNECTICUT. 193

ANALOG D PATO: CHEE LE EA.

Body nearly cylindrical; head fused with first segment of
thorax, forming together a kind of carapace, which contains a
small branchial cavity on each side. Coxal plates inconspicuous.
Abdomen usually of six segments the last one of which is much
the longest.

Second antennz smaller than first pair and originating directly
ventral to the latter.

Mandibles with or without palp. First maxille with a re-
flexed, setose palp. Second maxillze very small. Maxillipeds
coalesced at the base and each having an epignath projecting
within the branchial cavity.

First pair of legs very strong, curving anteriorly, with cheli-
form propodus. Second pair sometimes unlike the succeeding
ones which are simple and ambulatory.

Pleopods, when present, comparatively small and natatory,
with lamelliform rami. Uropods terminal, consisting of a short
peduncle and one or two terminal filaments.

TANAIDAL.

Body scarcely attenuated behind. First antennz without
accessory flagellum; flagellum usually rudimentary in female,
multiarticulate in male. Second antenne with rudimentary
flagellum.

Mandibles without palp. First maxillze with only a single
masticatory lobe. Second maxille represented by minute rudi-
mentary lobes. Maxillipeds with narrow, falciform epignath.

Second pair of legs not differing essentially from the follow-
ing pairs.

Pleopods with uniarticulate rami. Uropods simple or fur-
nished with two short filaments.

Tanais cavolinii Milne-Edwards.

1880. Tanais vittatus, Harger, Rept. U. S. Fish. Com. for
O70, Pe Ato, pl. 13, figs. 81, S2.
1899. Tanais tomentosus, G. O. Sars, Crust. Norway, vol.
2p ke. pls,
13

a
’ i
SORRY
\
yy wa
PSO Aaa F,_,
jE
ILL
SS —
———

194 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. | Bull.

Heo S&S S
i) a ae. ae
q 4, (| ( | 1o

Fic. 56. Tanais cavolinii.

1905. Tanais cavolinii, Richardson, Bull. U.S. Nat. Migss
No. 54, p..8.

Body elongate, between four and five times as long as wide,
and constricted at the articulations of the thoracic segments.
Head fused with the first segment of the thorax, about as long as
wide at the widest point, becoming gradually narrower toward the
anterior end, anterior margin triangularly produced with a very
obtuse apex. Eyes, small, compound, situated on short peduncles
at the antero-lateral angles of the head.

Antenne short, the first pair which is the longer, is subequal
in length to the head. First pair with first joint two-thirds as
long as head; second joint half as long as first ; third joint scarcely
as long as the second; terminal joint minute. Second antennz
shorter than first pair and more slender; first joint not quite as
long as the third; fourth joint longer than second and about
one-half as long as third; flagellum rudimentary, uniarticulate.

Mandibles without palp. First maxille with a single plate.
Maxillipeds with palp of four joints and well developed epignath.

Second and third segments of thorax subequal in length and
shorter than the succeeding ones. First pair of legs cheliform,
very large, with propodus longer than carpus. Second pair
with an especially long dactyl, much longer and more slender
than the succeeding ones which are all ambulatory.

Abdomen composed of five segments, of which the first three
are subequal in width to those of the thorax but somewhat
shorter, and the first is slightly longer than the two succeeding

No. 26.] ARTHROSTRACA OF CONNECTICUT. 195

subequal ones. First three segments with abundant sete on
lateral margins which are continued as transverse bands over the
dorsal side of the first and second segments near the posterior
margins. Last two segments much narrower than the preceding
ones; the fourth segment very short. The last segment is sub-
quadrangular and bears a triangular process at each side near
base. Pleopods, three pairs, consisting of a peduncle with two
semioval lamelliform rami. Uropods scarcely longer than last
two segments of abdomen; basal segment comparatively small;
second segment nearly as long as first, and third segment half as
long as the second.

Color brown, mottled with lighter above; nearly white beneath.

Length 5 mm.

The species occurs on piles and among alge and eel-grass
from I to 6 feet in depth. It is found on sponges, Balanus,
Laminaria, and oysters.

Distribution: Greenland, Norway, British Isles, Bermuda,
Azores, Mediterranean, Long Island Sound; Noank, Connecticut.

This species is readily recognized among the New England
Isopoda by the setze on the abdomen which are arranged on its
margins and in two transverse rows near the posterior margins
of its first two segments.

Leptochelia savignyi (Kro6yer).

TUS BaRS
aK see
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Ss

ee

Lg e ,
zi J] /T AK ———— 9) \ YN
Co av a fk \ Ng Sy }

Fic. 57. Leptochelia savignyt.

BEE LY)
Yih JV Pv

1874. Tanais filum, Harger, Rept. U. S. Com. Fish. for 1871-
2, pt. I, p. 573.

1879. Leptochelia algicola, Harger, Proc. U. S. Nat. Mus.,
Vole? p62.

1905. Leptochelia savignyi, Richardson, Bull. U. S. Nat.
Mus., No. 54, p. 26.

196 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Body of nearly uniform width throughout and not constricted
at the articulations; head longer than wide, anterior portion
narrower than posterior; first free thoracic segment the shortest ;
the two following ones subequal but not as long as the two suc-
ceeding segments, the last is shorter than the third. Abdomen
composed of six segments of which the five anterior ones are
subequal and somewhat broader than the thorax; last See
triangular, with rounded apex.

Eyes large, compound, supported on peduncles.

First antennz in female shorter than head, composed of three
segments of which the first is longer than the second and third
together, and the third is slightly longer than the second. In the
male the first antennze are about two-thirds the length of the
body and are composed of about eleven joints of which the first
is one-third as long as the whole appendage and curved some-
what ventrally. Second antennz in both sexes short, not reach-
ing as far as apex of first joint of first pair, slender, curved
downwards, terminated by a tuft of setz. :

First pair of legs in male much larger and more elongated
than in female; carpus elongate and cylindrical, extending about
one-half its length beyond the head; propodus robust and with a
strong curved digital process with two teeth, near the second
one of which are two stout sete; dactyl curved and provided on
inner margin with about seven short sete originating at the
bases of as many serrations. In the female, the first pair of legs
extends but little beyond the head; propodus with a stout, digital
process which is broadly notched near the base and is elevated
into.a slightly serrated lobe and bears at its apex a short, stout,
terminal tooth.

Second pair of legs, like all the following, ambulatory ; second
pair with dactyl more elongated than in succeeding legs, but
shorter than propodus. Third and fourth pairs of legs shorter
than second. Last three pairs with basal joints expanded and
dactyls short. ;

Uropods consisting of a robust peduncle and two rami, of
which the outer one is very small and uniarticulate, and the
inner One 1s six-jointed, tapering from the base, with the segments
of equal length and provided with sete near their distal ends.

Pleopods five pairs.

Length 2 mm.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 197

This species occurs abundantly among eel-grass and alge
from the surface to depths of 6 fathoms. It has been reported
from England, the Mediterranean, France, the Azores, Madeira
also from Provincetown and Woods Hole, Massachusetts ; Vine-
yard Sound; Long Island Sound; Noank, Connecticut ; Great Egg
Harbor, New Jersey.

It may be distinguished from the other Isopoda of the coast
by the following characters; the large and strong chelate first
pair of legs, the six-jointed abdomen, and the uropods with a
short, one-jointed outer ramus and six-jointed inner one.

Leptochelia rapax Harger.

1879. Leptochelia rapax, Harger, Proc. U.S. Nat. Mus., vol.
Ze) 1 OR: '

1880. Deena rapax, Harger, Rep. i S. Com. Fish. for
1878, p. 424, pl. 3, figs. 89, 9o.

This species has been reported only from Annisquam, Massa-
chusetts, and the Bermudas.

The female resembles quite closely that of L. savignyi
(Kroyer) but may be distinguished by the fact that the inner
ramus of the uropods is five-jointed instead of six-jointed. The
males are easily distinguished by the elongate and slender first
antennz and the much more slender and elongate carpus and pro-
podus of the first pair of legs; the carpus being about one-half
the length of the body and the propodus subequal to it.

Length 4 mm.

The species inhabits tubes.

CYMOTHOIDEA ot FLABELLIFERA,

First thoracic legs not cheliform; uropods lateral and form-
ing with terminal segment of abdomen a caudal fan; pleopods for
the most part natatory.

ANTHURID/.

Body long and slender, subcylindrical. Head comparatively
small. Segments of thorax well defined and without distinct
coxal plates. Abdomen comparatively short, with the anterior
segments sometimes coalesced, telson generally well defined,
linguiform.

198 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Both pairs of antenne, at least in female, short and subequal
in length, originating close together.

Mouth parts adapted for piercing and sucking.

Legs with basal and ischial joints slender. First pair gener-
ally much stronger than the succeeding ones, subchelate; the two
succeeding pairs likewise subchelate but weaker; last four pairs
ambulatory.

Pleopods chiefly branchial in character, first pair large and
more or less covering the others. Uropods with the outer ramus
extending upwards, so as to arch over the base of the telson.

Cyathura carinata (Kroyer).

1880. Anthura polita, Harger, Rep. U. S. Com. Fish. for
1878, p. 398, pl. 11, figs. 68, 69.

1886. Cyathura carinata, Norman and Stebbing, Trans. Zool.
Soc. London, vol. 12, pt. 4, p. 124.

1905. Cyathura carinata, Richardson, Bull. U. S. Nat. Mus.,
No. 54, p» 63.

Body more than seven times as long as wide. Head slightly
broader than long and deeply excavated on each of the front
angles for the bases of the first antenne.

Eyes small and lateral, distinct, situated on the outer side of
the anterior prolongations of the head.

First antenne with first and second peduncular joints subequal
in length; third joint a little shorter than second; flagellum con-
sisting of a single very short joint half as long as the third joint;
second joint furnished on lateral aspect with a row of sete.
Second antennz with first joint short; second joint twice as long
as first; third joint half as long as second; fourth joint shorter
than third; fifth joint as long as third; flagellum very short,
made up of one or two segments tipped with setze. .

Mandibles with three-jointed palp. maa with palp of
two joints.

First thoracic segment the longest; ‘nese segment shorter
but somewhat broader than the first and subequal in length to the
third, fourth, and fifth segments ; sixth and seventh segments pro-
gressively shorter. Coxal plates long and narrow, extending the
whole length of the segments and not separated by distinct su-
tures.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 199

Fic. 58. Cyathura carinata,

First pair of legs robust; basal joint and ischium large and
articulated to bring the leg well forward; merus short; carpus
triangular and extending along the side of the thickened propodus
for half the latter’s length; propodus subchelate, ovate, much
thickened and provided with a tooth-like process near middle of
palm; dactyl short and stout and tipped with a slender, curved
spine as long as the joint itself. Second and third legs quite
similar to each other, much more slender than first pair; carpus

200 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. | Bull.

very small and triangular. Succeeding legs more slender than
second and third; and with carpus longer than in préceding legs,
ambulatory. .

First six abdominal segments fused to resemble an eighth
thoracic segment which is a little longer than the seventh; in-
dications of the fusion of the first five visible along the sides.
Telson depressed at a steep angle, narrow, elongate, and rounded
posteriorly, sides nearly parallel, ciliated near the tip.

First pair of pleopods composed of a short quadrate peduncle
and two rami of which the outer one acts as an operculum, oval
in form with inner margin nearly straight; inner ramus much
smaller than outer, slender, with nearly parallel sides, rounded |
at tip and not ciliated. Uropods with elongated peduncle ex-
tending two-thirds the length of the telson.and obliquely truncated
distally where it articulates with the short, rounded inner ramus,
which is half as long as the peduncle and is setose on its outer
and apical margins; outer ramus lying directly on dorsal surface
of telson, extending as far as peduncle, triangular and narrow,
with acute apex, setose along its free superior margin.

Length 20 mm.

This species occurs from the surface to depths of 19%
fathoms on shelly and muddy bottoms, among eel-grass and
algee. Most abundant between tides or just below low water.

Distribution: Greenland; Denmark; also Gloucester, Massa-
chusetts ; Vineyard Sound; Providence, Rhode Island; off Block
Island; Noank Harbor, Connecticut; Long Island Sound; Great
Egg Harbor, New Jersey; Norfolk, Virginia.

This species is distinguished by the nearly complete union
of the anterior segments of the abdomen which have together
the appearance of an eighth thoracic segment.

Ptilanthura tenuis, Harger.
1878. Ptilanthura tenuis, Harger, Amer. Jour. Sci., ser. 3,
vol. 15, p. 378.
1880. Ptilanthura tenuis, Harger, Rep. U. S. Com. Fish.
for 1878-9, p. 406, pls. 11 and 12, figs. 71-74.
Body extremely narrow and elongate. Head as broad as
long, with anterior margin produced into a small, median, tri-

angular process. Eyes small, round, distinct, situated within the
margin of the head.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 201

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Fic. 59. Ptilanthura tenuis.

First antenne in the female shorter than second pair with a
very short flagellum consisting of a small basal segment and a
minute terminal one tipped with a few sete; first joint of
peduncle long; second and third subequal and slightly longer
than first. In the male first pair of antennz as long as head and
first two segments of thorax together; first segment large but not
longer than second, which is also longer than the third; flagellum
with first joint one-third as long as second joint of peduncle,

202 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

second joint of flagellum twice as long as first and bearing at

distal end a fringe of long slender sete; eighteen to twenty suc- .

ceeding joints similar to second one.

Mandibles and maxillipeds with uniarticulate palps.

First six thoracic segments subequal in length; seventh seg-
ment but little over half as long as preceding ones but broader
behind than any of them. First pair of legs with carpus nearly
equilaterally triangular, propodus moderately thickened, and
dactyl strong and tipped with a strong spine, carpus and pro-
podus with short sete on palmar margins. Succeeding pairs of
legs slender and of subequal size.

First five segments of abdomen consolidated along dorsal
line but distinct laterally, subequal in length and each one twice
as long as sixth joint. Telson long and narrow with rounded
apex. Uropods with peduncle half as long as telson; inner ramus
lamellar, triangular-ovate and extending as far as the telson;
outer or superior ramus narrowly semiovate, extending to end of
peduncle, somewhat triangular in shape, with acute apex.

Color brownish, more or less mottled above, lighter beneath.

Length 11 mm.; females about one-third smaller.

This species occurs from the surface to Jg fathoms and has
been taken from muddy bottoms; in sand, mud, and stones; at
low water, in sand.

Distribution: Grand Manan; Bay of Fundy; Casco Bay,
Maine; Vineyard Sound; off Block Island; off Watch Hill, Rhode
Island; Long Island Sound; Noank Harbor, Connecticut.

The species is rare on this coast.

CIROLANID/E.

Body more or less semicylindrical in form. Coxal plates well
defined except on the first segment. Head not produced medially.
Abdomen usually composed of six distinct segments.

Eyes not very large, lateral.

Antenne very unequal in length, the first pair being very
small, the second pair long, slender, and multiarticulate.

Mandibles with cutting part long, more or less trifid; molar
tubercle elongate, triangular. Maxillipeds well developed with
margins of palp furnished with many sete but not with hooks.

Legs ambulatory, although the first three pairs may also serve
for prehension.

——— == =

No. 26.] ARTHROSTRACA OF CONNECTICUT. 203

Pleopods well developed, adapted for swimming and respira-
tion. Second pair of pleopods in the male with a stylet inside the
inner plate. Uropods lateral, and forming with the well developed
terminal segment of the abdomen a caudal fan.

Cirolana concharum (Stimpson).

\
.

sy NG
iG
ae fi
é; =
GS

Fic. 60. Cuirolana concharum,

1874. Conilera concharum, Harger, Rep. U. S. Com. Fish. —
for 1871-2, p. 572.

1880. Cirolana concharum, Harger, Rep. U. S. Com. Fish.
for 1878-9, p. 378, pls. 9 and 10, figs. 58-63.

Body three times as long as broad. Head quadrate, wider than
long, anterior margin rounded, embraced at the sides by first
thoracic segment. Eyes small, triangular and with angles
rounded.

First antenne robust, arising immediately beside each other;
first and second segments subequal, each one-half as long as
third joint; flagellum robust, tapering, consisting of about fifteen
joints. Second antenne longer and more slender than first pair,
not in contact with each other at origin; first and second joints
short and subequal; third and fourth subequal and each as long
as two preceding together; fifth joint a little longer than fourth;
flagellum composed of about sixteen joints.

Mandibles robust, palp slender and triarticulate, with the
second segment the longest and setose on inner margin beyond
the middle, last segment slender and curved. Maxillipeds
elongated and almost pediform but flattened; palp five-jointed
with last four joints flat, broad, and densely setose.

204 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. | Bull.

Second and third thoracic segments subequal in length and
slightly shorter than the rest which are also subequal. Coxal
plates distinctly separated from their respective segments on all
but first segment. First pair of legs short and stout and well
armed with spines and sete ; ischium nearly triangular with upper
margin much produced distally and setose; carpus short and.
small; propodus robust, somewhat curved; dactyl strong and
short. Second and third pairs resembling first but with longer
carpus. Fourth pair of legs short like the preceding but
resembling the following except in size, provided abundantly
with fascicles of sete; propodus straight and much narrower than
carpus; fifth and sixth pairs of limbs increasing in size; last pair
somewhat smaller.

Abdomen slightly narrower than thorax, all six segments
distinct ; fifth segment longer dorsally but shorter laterally than
the preceding segments. Telson triangular, with setose apex
truncated and notched at tip. Uropods extending only a little
beyond the end of telson, provided with abundant long sete;
rami of equal length, but outer one only about one-third as wide
as inner one which has a notch on outer margin near posterior
end; inner angle of peduncle produced and extending about two-
thirds the length of the telson.

Length of large specimens 32 mm., average length 22 mm.

This species is found from the surface to. depths of 18
fathoms, on muddy and sandy bottoms.

It has been reported from Charleston, South Carolina; Curri-
tuck, North Carolina; Long Island Sound; Block Island; off
Fishers Island; Vineyard Sound; Woods Hole, Massachusetts.

According to the Woods Hole Survey, it is sometimes taken
in large numbers in winter from dead fish; and at Woods Hole
has been known to block up the cocks of the water supply of
the fish hatchery.

JEGIDAE.

Body more or less broad and depressed, dorsal surface evenly
vaulted and very smooth. Head comparatively small, broader

than long, front not produced above bases of antenne. Eyes,
when present, large.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 205

Antenne directed laterally; first pair shorter than second
pair and originating close together; both pairs with distinct
multiarticulate flagella.

Mouth parts adapted for piercing and tearing; first maxillz
with only a single lobe which is tipped with short spines. Second
maxillz armed with recurved teeth, as is also the terminal joint
of palp of maxilliped.

Thoracic segments with coxal plates defined distinctly except
on the first. First three legs short and thick, prehensile; last
four more slender and ambulatory.

Abdomen composed of six well defined segments, the last
one large, scutiform and ciliated on hind margin. Uropods
attached laterally beneath the terminal segment. Pleopods
adapted for swimming and respiration.

Parasitic, usually attached to the skin of fishes.

fHga psora (Linnzus).

Fic. 61 Aga psora.

1880. Aga psora, Harger, Rep. U. S. Com. Fish. for 1878,
p. 384, pl. to, fig. 64. “

206 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

1899. ga psora, G. O. Sars. Crust. Norway, vol. 2, p. 59,
pl. 24.

1905. AZga psora, Richardson, Bull. U. 5. Nat. Mus., No.
54, p- 168.

The following description is abbreviated from Harger’s. I
have not personally seen this species.

Body oval, broadest at fourth and fifth thoracic segments
where the breadth is about half the length; dorsal surface mod-
erately convex and smooth except for minute and scattered
punctations, which occur also on the legs, first antenne, uropods
and pleopods. Head transverse and subtriangular, salient in
front between the bases of the first antenne. Eyes very large
and reniform covering nearly all the upper surface of the head.

First antennee when bent backward attaining anterior margin
of first thoracic segment ; first two segments large and flattened ;
third joint cylindrical; flagellum tapering, made up of about a
dozen segments. Second antenne when reflexed extending
beyond first theracic segment; first two segments short and com-
pressed; third somewhat longer; fourth and fifth longer and
nearly cylindrical, followed by a tapering flagellum which is about
as long as peduncle and composed of fifteen to twenty segments.

First thoracic segment at anterior margin scarcely broader
than head, expanding rapidly backward, excavated in front some-
what for the accommodation of the eyes. Second, third, and
fourth segments each a little shorter than first; fifth and sixth
somewhat longer; seventh shorter than sixth. Coxal plates dis-
tinctly demarcated from segments except the first one; those of
second, third, and fourth segments rounded behind but those of
succeeding segments becoming acute and extending backwards.
First three pairs of legs short and armed with strong, hooked
dactyls ; fourth to seventh legs of different form, slender; seventh
pair only slightly developed in young but never quite as large
as sixth which is the largest.

Abdomen scarcely narrower than last thoracic segment and
scarcely tapering to the fifth segment. Last segment triangular,
with sides but little dilated and pointed at the tip. Uropods
scarcely exceeding the abdomen; peduncle with inner angle long
and spiniform, extending whole length of inner margin of inner
ramus and ciliated toward tip; rami flattenéd, outer one elongate

‘No. 26.] ARTHROSTRACA OF CONNECTICUT. 207

ovate, obtuse; inner with margin straight and outer margin
curved and emarginate near the tip. Both rami and posterior
portion of telson ciliated.

Length 50 mm.

Distribution: between delta of the Mississippi and Cedar
Keys, Florida; off Marthas Vineyard; Fishers Island Sound;
Gulf of Maine; Gloucester, Massachusetts ; Nova Scotia; Labra-
dor; Newfoundland; Gulf of St. Lawrence; Greenland; Hudson
Bay; Ireland; Iceland; North Sea; in the German Sea; Spitz-
bergen.

This species is parasitic on skates, cod, and halibut.

CYMOTHOIDA:.

Antenne strongly reduced and without clear distinction be-
tween peduncle and flagellum.

Mandibles with palp. First maxilla with a single lobe con-
sisting of a single joint furnished with four spines at the tip.
Second maxillz bilobed at the tip and provided with numerous
spines. Maxillipeds with two-jointed palp, the terminal joint of
which is furnished with hooks.

Coxal plates distinct on all the segments except the first. Legs
all prehensile, terminating in strong hooked dactyls.

Telson and uropods usually not ciliated.

Parasitic in habit.

fEgathoa oculata (Say).

1818. Cymothoa oculata, Say, Jour. Acad. Nat. Sci. Phila.,
vol, 1, p. 308.

1880. Aigathoa loliginea, Harger, Rep. U. S. Com. Fish. for
1878, p. 393, pl. 10, fig. 66.

Body elongate oval in outline, nearly four times as long as
broad, slightly dilated just posterior to the middle. Head broadly
rounded in front, as broad as long, and with posterior margin
produced in three equal shallow lobes. Eyes large, compound,
covering nearly half the area of head above, ae on postero-
lateral angles of head.

First antennz as long as head, composed of eight segments
and separated at base; first segment short and stout; succeeding
two a little longer but scarcely distinguishable from the five

208 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull
seements of the flagellum which decrease in size distally. Second
‘ S 1 : . .

antenne composed of about ten joints, more slender than the first
pair which they surpass in length; first two segments broader

than the succeeding three, which are larger than the five joints of |

the flagellum.

PSE

First thoracic segment shorter than head but longer than
segments two to six which are subequal in length; seventh seg-
ment one-third shorter than the sixth; fifth and sixth joints the
broadest. Coxal plates distinct on all the segments except the first
and as long as their respective segments. Legs differing but
slightly from each other; first pair the shortest; last four pairs
weaker than the preceding; seventh pair the longest.

Abdomen a little longer than thorax, becoming slightly
narrower posteriorly. Telson as broad at insertion of uropods
as third segment, and rounded behind. Uropods longer than
telson; outer ramus narrow, longer than inner one, with nearly

parallel sides and obliquely truncated tip; inner ramus rhom-.

boidal; peduncle with inner distal angle acute and only slightly

produced ; uropods and telson setose on posterior margins.
Color in alcohol, yellowish with minute black specks which are

most abundant on the abdomen. Eyes black, conspicuous.
Length 13 mm.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 209

Distribution: St. Thomas, West Indies; Crisfield, Maryland;
St. Johns River, Florida; Fort Macon, North Carolina; Savin
Rock, near New Haven, Connecticut.

The species is parasitic; one specimen was obtained from the
mouth of a squid by S. F. Clark in 1874 at Savin Rock; other
specimens were taken from young mullet at Fort Macon, North —
Carolina.

Livoneca ovalis (Say).

Fic. 63. Livoneca ovalis.

1818. Cymothoa ovalis, Say, Jour. Acad. Nat. Sci. Phila.,

vol. 1, p. 394.

1874. Livoneca ovalis, Harger, Rept. U. S. Com. Fish. for
1871-2, p. 572, pl. 6, fig. 29.

1880. Livoneca ovalis, Harger, ibid., for 1878, p. 395, pl.
ids ties OF.

I have never met with this species myself. The following is
from Mr. O. Harger’s description.

Body broad, oval, usually oblique and with the sides of un-
equal length; dorsal surface moderately convex. Head small,
rounded in front, trilobed behind, the middle lobe much the
largest, the two lateral lobes extending beyond the eyes which
are inconspicuous, small, and broadly separated.

14

210 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

First antennz widely separated at the base, with the first joint
short and stout; second longer and tapering; third about as long
as first; flagellum longer than peduncle, tapering, five-jointed.
Second antenne as long as first pair; first two joints short and
stout; the next three joints more slender; flagellum of three or
four joints.

First thoracic segment longest; next three a little shorter and
equal; fifth and sixth still shorter; and seventh the shortest.
Coxal plates narrow and obtusely pointed behind, but not ex-
tending beyond the posterior angle of their respective segments
except in the last two. First pair of legs short and stout; suc-
ceeding legs increasing in length posteriorly.

Abdomen tapering rapidly at the sides; first five segments
subequal in length; last segment as long as five preceding seg-
ments, flat and broadly rounded behind. Uropods surpassing
telson, with basal segment as long as rami and only slightly
produced at inner angle; outer ramus linear oblong, rounded at
end, inner ramus shorter and broader, oblique at the tip.

Length 17-22 mm., breadth 10-12 mm.

Distribution: Mobile, Alabama; Biloxi, Mississippi; Florida ;
Charleston, South Carolina; Virginia; Baltimore, Maryland; New
York; Long Island; New Haven, Thimble Islands, Connecticut ;
Woods Hole, Massachusetts; Vineyard Sound.

This species is parasitic on the blue fish, saw fish, scup, sea
trout, sun fish, etc. It is attached usually to the gills and roof of
the mouth.

LIMNORIIDE.

Body subdepressed and capable of being rolled into a ball.
Head short and very convex.

Antenne small, subequal in size.

Mouth parts normal, adapted for biting.

Coxal plates behind the first segment of thorax distinct and
laminar. Legs of uniform structure, ambulatory in function.

Abdomen composed of six well defined segments, the last of
which is very large and shield-shaped. Uropods compas
small, lateral; rami not lamelliform.

ee

No. 26.] ARTHROSTRACA OF CONNECTICUT. a

Limnoria ae (Rathke).

\

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~ Ry,
LON

SF,
SF, Ai

er

Fic. 64. Limnoria lignorum.

1841. Limnoria terebrans, Gould, Invert. Mass., pp. 338, 354.

1874. Limnoria lignorum, Harger, Rept. U. S. Com. Fish.
for 1871-2, p. 571, pl. 6, fig. 25.

1880. Limnoria lignorum, Harger, ibid., for 1878, p. 373.

1899. Limnoria lignorum, G. O. Sars, Crust Norway, vol. 2,
pe 7Onple,31-

Body three times as long as wide, oblong-ovate in form,
tapering somewhat in front. Head nearly globular, partly covered
above by first segment of thorax which is considerably longer
than the subequal succeeding ones. Coxal plates distinctly sepa-
rated on all the segments except the first. Eyes lateral, small,
composed of only a few ocelli.

First antenne stronger than second; flagellum extremely
small, triarticulate, with a dense fascicle of sete. Second
antennz with the flagellum about half the length of peduncle and
made up of five joints of which the first is much the largest.

First pair of legs larger than the succeeding ones but of the
same form. Last pair more slender than the others. Dactyls of
all the legs furnished with a large spine at the apex and a
smaller one on the concave margin near the apex.

Abdomen scarcely smaller than thorax, tapering but little;
first four segments of equal length; fifth much longer; telson
elliptical, broader than long, evenly rounded behind and fur- —
nished with sete. Uropods with peduncle strongly tuberculated

212 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

laterally and prolonged to an acute angle between the two rami,
the outer one of which is short and unguiform and the inner one
is sublinear, about the length of the peduncle and terminating
in a dense tuft of sete.

Color light grayish.

Length 4.5 mm.

Distribution: Coast of Great Britain; North Sea; Adriatic
Sea; coast of Norway ; Behring Island; Pacific Ocean; San Diego, |
California; from Florida to Halifax and the Gulf of St. |
Lawrence. |

It occurs above low-water mark but does not usually live far
below that line. It has, however, been found by Professor Verrill
at a depth of 10 fathoms in Casco Bay and has been dredged at
a depth of 7%4 fathoms in Cape Cod Bay.

This species may be recognized by its habits, being usually
found burrowing in submerged timbers, which it may penetrate
to the depth of half an inch.

SPHAZROMIDE.

Body short, oval. Convex, capable of being rolled into a
ball. Head transverse.

First and second antenne multiarticulate, with evident dis-
tinction into peduncle and flagellum.

Mandibles with palps.

Coxal plates united with their segments.

Abdomen with the anterior segments short and fused; last
segment large. Uropods lateral; outer ramus movable when
present ; inner ramus fixed.

Spheroma quadridentatum Say.

1818. Spheroma quadridentatum, Say, Jour. Acad. Nat. Sci.
Phila., vol. 1, p. 400.

1874. Sphcroma quadridentatum, Harger, Rept. U>S@aur
Fish. for 1871-2, p. 569, pl. 5, fig. 21.

1880. Spheroma quadridentatum, Harger, ibid., for 1878,
p. 368, pl. 9, fig. 53.

Body ovate, twice as long as wide. Head twice as broad as
long with a frontal border arising between the eyes and pro-

No. 26.] ARTHROSTRACA OF CONNECTICUT. 213

duced in a smalt median point. Eyes small, rounded, widely
separated, situated in the postero-lateral angles of the head.

G

ae

Fic. 65. Spheroma quadridentatum.

First pair of antennz inserted on under side of head and
fitting into groove when the animal contracts; first joint large;
second joint small and conical; third joint longer than second and
cylindrical in form; flagellum made up of about a dozen segments.
Second antennz longer than first pair, likewise inserted on under
side of head; first segment inconspicuous ; second segment short ;
third twice as long as second; fourth and fifth subequal and each
a little longer than the third; flagellum as long as peduncle and
composed of about fifteen segments.

Maxillipeds with basal segment short and somewhat tri-
angular and with five-jointed palp.

Segments of thorax subequal in length except the first which
is longer than the rest; coxal plates distinctly marked off from all
segments except the first; postero-lateral angles drawn out into a
narrow and subacute process which is more pronounced in the
first tour segments.

Legs weak, furnished with long sete, ambulatory; dactyl in
each case short and robust and provided with stout curved spine

214 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

at the tip; first pair with carpus short and triangular and ischium
and merus with long sete on upper margin ; second and third pairs
with longer carpus.

Abdomen composed of two segments; the first one of which
resembles the last thoracic segment but is marked at the sides by
two depressions indicating sutures. Telson long and widely:
rounded posteriorly, rather strongly contracted laterally at inser-
tion of uropods.

Uropods extending beyond end of telson; inner ramus with
smooth margins; outer margin subequal to the inner in length
and width, with three or four wide serrations on outer margin.

Color extremely variable, some individuals of a uniform slatey
gray; many marked dorsally with a whitish, creamy, or pinkish
patch margined with black.

Length 8 mm.

Distribution: Florida; Georgia; Virginia; Beaufort, North
Carolina; Great Egg Harbor, New Jersey; Savin Rock, near New
Haven, Stony Creek, Connecticut ; Provincetown, Massachusetts ;
Vineyard Sound.

It is found in abundance under stones or creeping about the
branches of seaweeds from low-water mark nearly to high-water
mark.

When disturbed this species curls itself up into a ball with
facility and drops to the bottom. By this habit of rolling itself
into a ball it may be distinguished from all other marine Isopoda
of the coast.

IDOTHEOIDEA or VALVIFERA.

First thoracic legs not cheliform.

Uropods lateral, situated ventrally and opening and closing
like valves over the five pairs of branchial pleopods; and attached
on the outer margins to the terminal abdominal segment.

IDOTHEIDZ::

Body more or less depressed, with segments of thorax of
uniform appearance. First pair of antenne with uniarticulate
flagellum. Second antenne with flagellum uni-or multiarticulate.

Mandibles without palp.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 215

Coxal plates sometimes distinct, sometimes fused with their
segments. Legs rather strongly built, increasing in length
posteriorly ; three anterior pairs sometimes strongly subcheliform.

Abdomen with some or all its segments consolidated to form
a large termina! plate. Uropods very large, lamelliform, valve-
like.

Chiridotea cceca (Say).

i—

SUES ow Oy
See.

ee MDs

Qh
7 fe

\
Se, Sey
FG Bt y
: 4

Fic. 66. Chiridotea ceca.

y/

1818. Idotea ceca, Say, Jour. Acad. Nat. Sci. Phila., vol. 1,
Pp. 424.

1841. Jdotea ceca, Gould, Invert. Massachusetts, p. 337.

1880. Chiridotea ceca, Harger, Rept. U. S. Com. Fish. for
1878, p. 338, pl. 4, figs. 16-19.

1905. Chiridotea ceca, Richardson, Bull. U. S. Nat. Mus., -
No. 54, Pp. 353:

Body ovate, broad and short, tapering to acutely pointed
extremity ; abdomen nearly one-half as long as whole body. Head
only slightly excavated in front for the antennz, with a triangular
process not extending beyond the line of the front margin; deeply
notched also at antero-lateral angles. Eyes small, inconspicuous,
round, situated at base of posterior lateral lobe of head.

First antennz longer than peduncle of second pair; first joint
very short and not dilated; second joint strongly clavate and

216 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. | Bull.

longer than first ; third and fourth joints equal in length and each
about twice as long as first. Second antennz with first joint
very short: second, third, and fourth joints subequal; fifth joint
a little longer than the fourth; flagellum made up of five joints
and exceeding in length the last two joints of the peduncle.

Thoracic segments subequal in length and broader than its
mid-dorsal length; first segment broadly excavated for head.
Coxal plates distinctly marked off from their segments except the
first pair; last four pairs produced behind into acutely pointed
processes. First three pairs of legs subchelate, with propodus
swollen and dactyl short and reflex ; last four pairs of legs ambu-
latory and similar in form and increasing in length to the sixth
which is the largest; all the legs with abundant sete.

Abdomen composed of four segments; first three quite short,
broadening somewhat posteriorly. Telson acutely pointed with
lateral sutures of at least one more coalesced segment; lateral
margins near extremity denticulated, converging for their anterior
half gradually, and then more rapidly to the apex. Opercular
valves ciliated along postero-external margin, in two parts, the
small terminal part representing the outer ramus of the uropods;
inner ramus attached to peduncle on the external side.

Its color in life is variable but usually dark grayish. There
may be a mottling of light yellowish gray at the sides of the head
and body.

Length 12-15 mm.

Distribution: Florida; New Haven, Connecticut ; Long Island
Sound; Woods Hole, Provincetown, Nantucket, Nahant, Massa-
chusetts; Vineyard Sound; Halifax, Nova Scotia.

This species is common on sand beaches at many localities on
the New England coast and Long Island Sound. It is usually
found below high-tide mark or burrowing just beneath the sur-
face throwing up a little ridge like a mole, and making a little
mound at the end. It swims with ease. It is distinguished from
the following species by its large size and shorter second antennz
which are but little longer than the first pair. From other New
England Isopoda it may be distinguished by the broad subcircu-
lar thorax, the articulated flagellum of the second antenne, and a
two-valved abdominal operculum.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 217

Chiridotea tuftsii (Simpson).

Fic. 67. Chiridotea tuftsu.

1853. IJdotea tuftsu, Stimpson, Marine Invert. Grand Manan,
Pp. 39.

1874. Idotea tuftsu,, Harger, Rept. U. S. Com. Fish. for
1871-2, p. 569.

1880. Chiridotea tuftsii, Harger, ibid., for 1878, p. 340, pl.
4, figs. 20-23.

1905. Chiridotea tuftsu, Richardson, Bull. U. S. Nat. Mus.,
No. 54, p. 354-

Body ovate, less than twice as long as wide. Head twice as
wide as long, with the front deeply excavate between the antero-
lateral angles, and produced in a small median point; lateral
margins bilobed, the posterior lobe being produced laterally
beyond the anterior one. Eyes small, round, more distinct than
in the preceding species, situated just within the cleft on the
lateral margin.

First antennz with first joint large and dilated; second joint
longer than first, and third longer than second; flagellum made
up of a single segment as long as the last two joints of the pedun-
cle together, setose; shorter than the peduncle of second antenne.
Second antennze with first segment short; second joint twice as

long as the first; third joint a little shorter than the second;

218 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

fourth joint as long as second; fifth joint as long as the two
preceding together; flagellum of about a dozen segments and
longer than peduncle.

First segment of thorax deeply excavate in front to accommo-
date the head. Coxal plates distinctly marked off from their
segments except the first pair, postero-lateral angles of last four
acutely produced. First three pairs of legs subchelate; first pair
a little shorter than second and third pairs but with much more
robust propodus; fourth to seventh pairs ambulatory, less spiny
but more setose than in preceding species.

Abdomen composed of four distinct segments of which the
last one is twice as long as wide and has lateral sutures indicat-
ing a partly coalesced segment, setose at the acutely pointed tip.

Color usually light reddish brown, speckled with darker, or
marked with dark transverse patches or bands.

Length 9 mm.

Distribution: Halifax, Nova Scotia; Bay of Fundy; Eastport,
Maine; Casco Bay; Gloucester Harbor, Massachusetts Bay;
Long Island Sound; off New London, Connecticut.

It is found to depths of 25 fathoms. It is also found on sandy
shores similar to the preceding species, but is rather more rare.
Its habits are essentially the same as those of C. cwca but it can
be distinguished from that species by its smaller size and its
much longer second antennz, which are about twice as long as
the first pair, as well as by its more conspicuous eyes.

Idothea metallica Bosc.

1874. Idotea robusta, Harger, Rept. U. S. Com. Fish. for
1871-2, p. 569, pl. 5, fig. 24.

1880. Idotea robusta, Harger, ibid., for 1878, p. 349, pl. 6,
figs. 30-32.

1905. Jdothea metallica, Richardson, Bull. U. S. Nat. Mus.,
No. 54, p. 362.

Body oblong-ovate about two and one-fourth times as long
as wide; abdomen nearly one-half as long as whole body.

Head wider than long, with front margin slightly excavate,
slightly wider behind than in front. Eyes large and round, com-
pound, and situated at the extreme lateral margin.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 219

First antenne extending to end of second joint of second
antenne, with first and second joint not enlarged and subequal;
third and fourth joints subequal and each somewhat longer than
either of the preceding. Second antennze with first joint very
short ; second and third joints subequal; fifth joint a little longer
than the fourth which in turn is longer than the third; flagellum
composed of eight joints.

Thoracic segments subequal ; first embracing the head slightly
on either side; lateral portions of the segments curved outward
and somewhat upward forming an angle with the portion of the
segment to which it is adjacent. Coxal plates from the second
to the seventh inclusive, extending entire length of each segment,
and very large and wide, increasing in width to the seventh, and
giving a serrated appearance to the sides of the thorax. °

Legs all more or less alike in character, robust, and with
free margins of all the joints and lower margin of the propodus
setose.

Abdomen composed of two short segments and a long telson
with indications at the sides of coalescence of another short seg-
ment. Telson with sides nearly parallel beyond the middle and
broadly truncate or even slightly emarginate behind. Basal plate
of operculum elongated and with parallel sides; terminal plate
less than one-fourth as long and tapering slightly.

Length of male 28 mm.; of female 22 mm.

Distribution: Patagonia; New South Wales; Borneo; be-
tween Montevideo and Straits of Magellan; southwestern Ire-
land; Mediterranean; Florida Keys; North Carolina; off Mary-
land; Chesapeake Bay; south shore of Long Island; Vineyard
Sound; Woods Hole, Massachusetts; Newport, Rhode Island;
off Marthas Vineyard; near Isles of Shoals; Halifax, Nova
Scotia. -

This species is pelagic, it is found swimming free as well as
among masses of floating seaweeds.

It is easily distinguished from other species of the genus by
the telson which is broadly truncate and not the least pointed.
From other genera of the New England coast, Jdothea is dis-
tinguished by the abdomen of apparently four segments of which
the first three are short and the third is united in the dorsal region
to the large vaulted telson; by the conspicuous two-valved oper-

220 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

culum, and the several segments of the flagellum of the second

antenne.

Idothea baltica (Pallas).

Fic. 68. IJdothea baltica.

1841. Stencsoma irrorata, Gould, Invert. Mass., p. 338.

1853. Idotea irrorata, Stimpson, Smithson. Contrib. Knowl.,
vol. 6, p. 39.

1874. Idotea irrorata, Harger, Rept. U. S. Com. Fish. for
1871-2, p. 569, pl. 5, fig. 23; also ibid., for 1878, p. 343, pl. 5,
figs. 24-20.

1883. Jdotea marina, Miers, Jour. Linn. Soc. London, Zool.,
vol. 16, p. 25.

1899. Idothea baltica, G. O. Sars, Crust. Norway, vol. 2, p.
80, pl. 32. .

1905. Idothea baltica, Richardson, Bull. U. S. Nat. Mus.,
No. 54, p. 364.

Body oblong-ovate, three times as long as wide; abdomen
slightly more than one-third as long as whole body. Head wider
than long, slightly excavated in front and narrowing behind.
Eyes, large, round, conspicuous, compound, situated just anterior
to the median transverse line of the head and at the extreme
lateral margin.

First pair of antennz with first joint equal in length to the
second and not expanded; third and fourth joints slightly longer

—

No. 26.] ARTHROSTRACA OF CONNECTICUT. 221

than either of the preceding ones; scarcely exceeding in length
the first three joints of the second pair. Second antenne with
first three joints rather short and subequal in length; fourth
joint longer than third, and fifth still longer, being twice as long
as the third; flagellum of about a dozen segments of which the
first is by far the longest and a little longer than the peduncle.

Thoracic segments about equal in length. Coxal plates dis-
tinct from their segments and forming a nearly even curved out-
line, the segments being marked by incisions instead of serrations
as in the other species.

Legs more or less alike in structure and increasing in length
posteriorly ; the first pair much stouter than the succeeding ones.

Abdomen of two short segments followed by a long one which
shows indications of coalescence of a third short segment, lateral
angles of first two abdominal segments acute. Telson with lateral
margins slightly convex and with apical margin produced in
middle to an acute point which extends some distance beyond the
lateral angles. Operculum with peduncle three times as long as
the terminal ramus which is broadly truncate at the apex.

Color varying greatly ; frequently nearly uniform light or dark
green, or brownish with blackish punctations. Females usually
darker than the males which often have a median dorsal stripe.

Length of males 30 to 38 mm.; of females 20 mm.

Distribution: Java; Red Sea; New Zealand; Scandinavian
coast ; Baltic Sea; west coast of Europe to Great Britain; Medi-
terranean ; Caspian, and Black Seas; Bermuda; Barbadoes; Rio
Janeiro; North Carolina north to Nova Scotia and the Gulf of
St. Lawrence. Within Connecticut the species has been collected
at New Haven, Stony Creek, Lyme, Noank, and off Stonington.
From Cape Cod southward the species is abundant, but towards
the north it is replaced by J. phosphorea.

The species occurs on the surface, on floating seaweeds, some-
times far from land. More commonly it is found among sea-
weeds along the rocky shores of bays or sounds, and among the
rocks at low water. In the Woods Hole Survey it was occasion-
ally brought up in the dredge while operating at depths as great
as 13% fathoms; but the specimens may have been taken in these
cases near the surface.

CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

to
to
bo

Idothea phosphorea (Harger).

(; (\) ecm ae
x 2 soe
an Oe wa Arey , Y,
Rs
CP) UR
2 tine
4 AA =f — Y |
(25M fy ae ‘ cy | ee
CX (7 W 4 ise

Fic. 69. Idothea phosphorea.

1874. Idothea phosphorea, Harger, Rept. U. S. Com. Fish.
for 1871-2, p. 560.

1880. Idothea phosphorea, Harger, ibid., for 1878, p. 347,
pl. 5, figs. 27-29.

1905. Idothea phosphorea, Richardson, Bull. U. S. Nat.
Mus., No. 54, p- 367.

Body oblong-ovate, slightly more than three times as long as
wide; length of abdomen equal to greatest width of body. Head
broader than long, with anterior margin straight on either side of
a very slight median excavation. Eyes moderately large, round,
compound and placed just in front of the median transverse
line of the head at the extreme lateral margin.

First antennze with first joint but little wider than second one,
each of which is subequal in length to the third joint; fourth
joint a little longer than any one of the preceding; extending to
end of third peduncular joint of second pair. Second antennz
with first joint inconspicuous and second and third joints subequal
in length; fifth joint longer than fourth which in turn is longer

than the third; flagellum shorter than peduncle and made up of

about a dozen segments.

Thoracic segments subequal in length, except the first which
is shorter in the mid-dorsal line. Coxal plates distinctly marked
off from their respective segments, except in the case of the first
segment, and each one in turn occupying a larger part of the
lateral margins and becoming wider posteriorly. Legs of more

No. 26.] ARTHROSTRACA OF CONNECTICUT. 223

or less similar structure throughout and furnished with sete
along inferior margin of merus, carpus, and propodus.

Abdomen of two short, free segments and a long telson show-
ing indications of a partial coalescence of a third short segment.
Telson tapering to a pointed apex, lateral margins exhibiting an
obtuse, rounded angle behind the middle so that the posterior
part tapers more acutely than anterior part. Operculum with
basal plate tapering toward the end and with triangular terminal
ramus which is a little longer than broad.

Color very varied, usually dark green or brownish with
patches of yellow or whitish. In general the color is darker than
in J. baltica.

Length 25 mm.

Distribution: coast of New England to Halifax, Nova Scotia,
and the Gulf of St. Lawrence.

This species is found in conditions similar to the preceding
one but is a more northern form as it is comparatively rare south
of Cape Cod while it is abundant in Casco Bay and the Bay of
Fundy. It has been collected within the limits of Connecticut at
New Haven, Stony Creek, off Saybrook, and Noank Harbor.

It is readily distinguished from the other species of the same
genus by the pointed telson.

Edotea triloba (Say).

1818. Idotea triloba, Say, Jour. Acad. Nat. Sci. Phila., vol.
I, p. 425.

1874. Epelys trilobus, Harger, Rept. U. S. Com. Fish. for
LOzt-2,)p: 571,-pl..6, hig. .28.

1880. Epelys trilobus, Harger, ibid., for 1878, p. 358, pl. 7,
fig. 42-43.

1905. Edctea triloba, Richardson, Bull. U. S. Nat. Mus., No.
54, p- 390.

Body ovate, nearly two and one-half times as long as wide;
abdomen less than one-third as long as whole body. Head pro-
duced slightly in front with two conspicuous tubercles very close
together on either side of middle line, situated on front margin;
antero-lateral angles of head produced in rounded lobes upon
which the prominent eyes are placed.

224 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. {[ Bull.

First pair of antenne longer than the second pair; first and
second joints equal in length ; third joint twice as long as second;
fourth joint about two-thirds as long as preceding. Second
antenne reaching only to middle of fourth joint of first pair;
shorter than head; fourth joint one and a half times as long as
third which is subequal in length to each of the first two joints ;
fifth joint a little longer than the fourth; flagellum minute, com-
posed of a single joint which is about one-third as long as the
fifth joint.

DEORE.

yan
eg le.
iS

Fic. 70. Edotea triloba.

Third and fourth joints of thorax longer than any of the
others and also the widest. Coxal plates of none of the segments
distinctly separated; their lateral margins, especially in front,
almost straight. Dorsal side of body characterized: by two. longi-
tudinal depressions which divide it into a middle lobe and two
lateral ones which bear each a rounded tubercle. Legs prehensile
and slender with dactyls which are almost acicular; first pair by
far the shortest.

Abdomen composed of a single segment with slight incisions
near the base indicating another segment partly coalesced ; telson
with a large rounded prominence situated in the median line at

No. 26.] ARTHROSTRACA OF CONNECTICUT. 225

the base, followed by a depression so that in a lateral view the
abdomen is seen to be in the form of two elevations separated
by a deep depression; apex of telson also separated from second
elevation by another depression; sides converging rapidly below
the middle to a narrow, pointed apex.

Color uniform, dull, usually obscured by adhering particles
of dirt.

Length 7 mm.

Distribution: Great Egg Harbor, New Jersey; Staten Island;
Savin Rock, near New Haven, Noank Harbor, Connecticut ;
Watch Hill, Rhode Island; Vineyard Sound; Provincetown,
Gloucester, Massachusetts; Quahog Bay, Casco Bay, Maine.

The species occurs among eel-grass, on piles, and in sheltered
places among decaying vegetation and mud on the bottom, from
the surface to 3 feet in depth. It is usually covered with adher-
ing dirt.. .

It may be recognized among the native Isopods by the trilobed
character of the back, the abdomen of a single segment, and the
second antennz with only a rudimentary flagellum.

Edotea montosa (Stimpson).

1853. Idotea montosa, Stimpson, Smithson. Contrib. Knowl.,
vol, 6; p40.

1874. Epelys montosus, Harger, Rept. U. S. Com. Fish. for
1871-2, p. 571.

1880. Epelys montosus, Harger, ibid., for 1878, p. 359, pl.
8, figs. 44-47.

1905. Edotea montosa, Richardson, Bull. U. S. Nat. Mus.,
No. 54, p. 397.

Body ovate, a little more than twice as long as wide; abdomen
slightly more than one-third as long as entire body. Head with
front margin triangularly produced and with two low tubercles
situated on the anterior margin. Eyes placed on the antero-

~ lateral lobes which are rounded. F

First antenne with first and second joints equal in length,
third joint twice as long as first, fourth joint slightly more than
half as long as third. Second pair of antennze extending not
quite as far as third joint of first pair, with first three joints
subequal and fourth and fifth successively longer; flagellum com-

15

226 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

posed of a single joint one-half as long as fourth joint of

peduncle.
Maxillipeds with triarticulate palp. y
a ¢ fe
Sosa Oe aes
AS “NZ Biel
hi
a
NS oe b

Oey ae A
a” i } i &
Ney

Fic. 71. Edotea montosa.

Third and fourth thoracic segments longer and wider than
any of the others. Epimera firmly united with their respective
segments but demarcated by a slight linear depression, with
rounded margins.

Legs all prehensile ; first pair much shorter than the other six.

Abdomen composed of a single segment which represents two
coalesced as shown by lateral incisions at the base of the abdomen
and a slight depression extending inwards a short distance on
either side; dorsal surface with a depression just behind the level
of the lateral incisions and another one near the extremity sepa-
rating off the small terminal point from the large median eleva-
tion; sides of abdomen converging to a triangular apex.

Length 9 mm.

Distribution: Block Island Sound; Long Island Sound; Vine-
yard Sound ; Eastport, Maine; Georges Bank; Stellwagens Bank;
Casco Bay; Bay of Fundy; Halifax, Nova Scotia; Grand Manan.

The species occurs in mud and fine sand at depths of from 8

No. 26.] ARTHROSTRACA OF CONNECTICUT. 227

to 25 fathoms, and is always concealed by an adhering layer of
mud.

It is distinguished from the preceding species by the more
rounded lateral margins of the body, the different form of the
abdomen, and the absence of tubercles on the lateral portions
of the thoracic segments.

Erichsonella attenuata (Harger).

Fic. 72. Erichsonella attenuata.

1874. Erichsonia attenuata, Harger, Rept. U. S. Com. Fish.
for 1871-2, p. 570, pl. 6, fig. 27.

1880. Erichsonia attenuata, Harger, ibid., for 1878, p. 356,
pls. 6 and 7, figs. 36 and 37.

1905. Erichsonella attenuata, Richardson, Bull. U. S. Nat.
Mus., No. 54, p. 400.

Body narrow, elongate, about five times as long as wide;
abdomen one-fourth as long as entire body. Surface of body
smooth throughout. Head wider than long with anterior margin
slightly excavate between the prominent antero-lateral angles,
with a prominent elevation between the eyes, which are small,
compound, and situated half way between anterior and posterior
margins of the head on the lateral margins.

First pair of antennz with first joint large and dilated; second
joint a little shorter than the first and half as wide; third and
fourth joints subequal in length and each one and a half times as
long as the second; extending slightly beyond the second joint

228 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

of the second antenne. Second antenne more than half as long
as body with the peduncular joints increasing in length to the
fourth: fifth joint a little shorter than fourth; flagellum made up
ofa single joint a little longer than fourth joint.

First segment of thorax slightly shorter than any of the others
except the seventh; second to fifth segments subequal in length ;
sixth joint, a little shorter than the preceding ones ; third segment
broadest. Coxal plates distinctly separated on all the segments
including the first, placed in the first three segments on the
lateral margin anterior to the middle, in the fourth segment at
the middle, and in succeeding segments behind the middle; pro-
ducing a somewhat angular appearance to the otherwise very
even outline of the body. Legs ambulatory and furnished with
bi-unguiculate dactyls.

Abdomen composed of only a single segment; with a small
lateral process on either side about one-third the distance from
the base to posterior end; posterior to the lateral processes the
sides are parallel for about one-half the distance and then con-
verge to a rounded apex. Operculum with basal plate more than
three times as long as broad, and terminal plate elongated and
obtusely triangular.

The color in life is usually uniform dark green, sometimes
with an obscure dorsal stripe of a lighter color.

Length 15 mm.

This species has been collected at Great Egg Harbor, New
Jersey; and Noank, Connecticut. It is not a common species
although it was abundant on eel-grass at the first mentioned
locality in April, 1871.

It may be distinguished from the other genera of isopoda of
Connecticut by the flagellum of the second antennz which is
clavate and from the following species by its slender form and
regular outline.

Erichsonella filiformis (Say).
1818. Stenosoma filiformis, Say, Jour. Acad. Nat. Se Phila.,
vol. I, p. 424.
1874. Erichsonia filiformis, Harger, Rept. U. S. Com. Fish.
for 1871-2, p. 570.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 229

1880. Erichsonia filiformis, Harger, tbid., for 1878, p. 355,
pl. 7, figs. 38-41.

1905. Erichsonella filiformis, Richardson, Bull. U. S. Nat.
Mus., No. 54, p. 401.

Fic 73. Erichsonella filiformis.

Body oblong-ovate, about three and one-half times as long as
wide; abdomen as long as greatest width of body. Head with
front margin deeply excavate between the prominent antero-
lateral angles; dorsal surface of head with a prominent, rounded
elevation bearing two slender, rounded tubercles, one on each
side of the middle line. Eyes large, round, compound, situated
at about the middle of the head at the extreme lateral margins.

First antennz with basal joint large and dilated; second and
third joints subequal and only slightly shorter than first; fourth
joint a little longer than third; extending to end of third joint
of second antennz. Second antenne with first joint very short;
second and third joints subequal in length and equal to the first
two joints of the first antenne combined; fourth joint nearly
twice as long as third; and fifth shorter than fourth; flagellum
clavate, as long as fourth joint, extending when retracted about
as far as hind margin of fifth thoracic segment.

230 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Thoracic segments, each with a smaller median tubercle near
its posterior margin; first two segments with lateral margins pro-
duced in very acute processes, one on either side of each segment ;
lateral parts of third and fourth segments produced on each side
into two acute processes of which the anterior one is the larger;
last three segments with anterior part of lateral margin acutely
produced. Coxal plates distinct, that of first segment being acute
and anterior in its position; that of the second being bilobed, the
upper division concealing the smaller acute lower one; coxal
plates of third and fourth segments acute but not very con-
spicuous ; those of the last three segments also acute and attached
to posterior part of segment. This condition of the coxal plates
and lateral margins gives the appearance of fourteen teeth on
each side of the thorax. Legs all more or less similar and
terminated by a subchelate propodus and dactyl.

Abdomen composed of a single segment which is produced
on either side in an acute angular process about one-third the
distance from the base to the apex; lateral margins diverging very
slightly behind the angular processes for one-third the length
of the abdomen and then converging rapidly to a triangular apex
which is rounded. Operculum a little more vaulted and shorter
than in the preceding species; basal plate less than three times
as long as wide, terminal plate triangular.

Color usually dull, neutral tint without bright markings.

Length 11 mm.

Distribution: The Bahamas ; Florida; Great Egg Harbor, New
Jersey; Long Island Sound ; Vineyard Sound; Nantucket Sound;
Fishers Island Sound; Thimble Islands and Noank, Connecticut.
It is usually found in tide-pools or among eel-grass and alge and
in sand and gravel to a depth of 18 fathoms.

The species may be distinguished by the clavate flagellum of
the second antenne and the strongly serrated outline of the sides.

ASELLOIDEA or ASELLOTA,

First thoracic legs not cheliform; uropods terminal, biramous ;
outer branch of pleopods never two-jointed; pleopods exclusively

branchial, generally covered by a thin opercular plate (the modi-
fied first pair).

No. 26.] ARTHROSTRACA OF CONNECTICUT. 231

Second pair of antennz elongate.
Epimera very small or obsolete.
Abdominal segments all fused together forming a broad,
shield-like plate.
Mouth parts normal; maxillipeds furnished with an epipod
and five-pointed palp.
ASELLIDZ.

Body broad, depressed. Head without rostrum. Caudal
segment large, shield-like. Eyes small, lateral.

Antenne with multiarticulate flagella; superior pair much
smaller than inferior pair.

Mouth parts normal.

Pereiopods ambulatory, except the first pair which are sub-
chelate.

Pleopods, four pairs in female; the first very small, not oper-
culiform; the three succeeding pairs biramous and lamelliform;
the outer ramus of second pair forming an operculum. In male,
five pairs of pleopods, an additional one between the first and
second forming the copulatory organs.

Uropods large, biramous, with rami styliform or lamellar.

' Asellus communis Say.

1818. Asellus communis, Say, Jour. Acad. Nat. Sci. Phila.,
vol. 5,p,7427:

1841. Asellus vulgaris, Gould, Invert. Mass., p. 337.

1905. Asellus communis, Richardson, Bull. U. S. Nat. Mus.,
‘No. 54, p. 420.

Body oblong-ovate, about three times as long as wide; thorax
and abdomen of equal width. Head narrower in front than
behind and with anterior margin excavate. Eyes small, round,
compound, situated laterally half way between front and hind
margins.

First antennz extending to the middle of last joint of second
pair; second joint longer: than third which in turn is longer
than the first; flagellum made up of about fourteen joints.
Second antennz more than half as long as body; fifth joint of
peduncle one and two-thirds as long as fourth joint which equals
the length of the first three joints together; flagellum much
longer than peduncle,

232 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull

Mandibles with triarticulate palp. Maxillipeds with five-
jointed palp.

First pair of legs subchelate; carpus very minute, propodus
oblong, with hind margin bearing several stout spines at junction
with palm ; dactyl nearly as long as propodus and deeply serrated.
Succeeding legs with numerous spines; merus prolonged on
anterior margin and armed with a group of long spines. Coxal
plates very small.

Fic. 74. Asellus communis.

Abdomen composed of two short segments which are visible
only on the mid-dorsal line and a large terminal one which is
nearly as long as it is wide and has the postero-lateral angles
rounded and the posterior margin produced in a broad triangular
process between the uropods. Uropods as long as last segment
of abdomen; rami styliform, inner ramus as long as peduncle,
outer one about two-thirds as long.

Length 15 mm.

Distribution: Potomac River; Schuylkill River, Pennsylvania;
Cincinnati, Ohio; Mississippi; Michigan; Illinois; Indiana;
Massachusetts; Rhode Island; New Haven, Canaan, Berlin,
Connecticut.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 233

This is a very abundant species, occurring everywhere in
brooks and ponds, under stones, and crawling over the stems of
water weeds. It is very tenacious of life; a single specimen
survived in a vial containing a small amount of clean water for
a space of three months, with nothing to feed on except possibly
the cork of the vial which lay on its side for part of the time.
This specimen, together with several others about 5 mm. in length,
was brought to me by Mr. S. C. Ball who found them in water
drawn from a faucet in New Haven in 1910.

JANIRIDZ.

General appearance like that of the Asellide but with the
lateral margins of head always lamellarly expanded. Eyes, when
present, subdorsal.

First antennze sometimes well developed, with multiarticulate
flagellum, sometimes very small and with rudimentary flagellum.
Second antenne always longer than first pair, with peduncle of
six segments and with small scale-like appendage external to the
third joint.

Mouth parts normal.

Legs subequal in length, with dactyls bi- or tri-unguiculate ;
first pair sometimes ‘differing from others in being prehensile.

First pair of pleopods in female in form of single, large oper-
cular plate; in male constituting the median piece of the com-
pound operculum, the lateral pieces of which are formed by the
copulatory organs. Uropods biramous.

Jera marina (Fabricius).

1853. J@ra copiosa, Stimpson, Smithson. Contrib. Knowl.,
WoL Ossp:f Ao; ply.3e fis, 20.

1868. Jera albifrons, Bate and Westwood, Brit. Sess. Crust.,
Vols 2p: 3217:

ioe wiwera copiosa,« Larger, Rept, U.S: ‘Com. Fish.) for
1871-2, p. 571.

1880. Jera albifrons, Harger, ibid., for 1878, p. 315, pl. 1,
figs. 4-8.

1899. J@era marina, G. O. Sars, Crust. Norway, vol. 2, p.
104, pl. 43.

234 CONNECTICUT GEOL. AND NAT. HIST. SURVEY... [Bull

Fic. 75. J@era marina,

1905. Jeera marina, Richardson, Bull. U. S. Nat. Mus., No.
54, P- 450.

Body oblong-ovate, about twice as long as wide; abdomen
one-half as long as greatest body width. Head twice as wide as
long, with front margin produced in middle in a large rounded
lobe; lateral margins straight and sparsely setose, postero-
lateral angles rounded, antero-lateral angles not greatly produced.
Eyes small, oval, compound, situated dorsally near posterior
margin of head.

First antenne with first joint large and dilated; second joint
much narrower and slightly shorter than first; succeeding joints
each decreasing in length and width; flagellum of two joints;
not extending to fourth segment of second antenne. Second
antenne with first three joints short and subequal; fourth joint
robust and as long as first three combined; fifth joint the longest ;

No. 26.] ARTHROSTRACA OF CONNECTICUT. 235

flagellum composed of about eighteen segments and reaching as
far as hind margin of fifth thoracic segment.

First three thoracic segments subequal in length and longer
than the last four which are also subequal in length, except the
fifth which is shorter than the preceding. Lateral margins
sparsely setose and projecting so as to cover the basal joints of
the legs but coxal plates not distinct, lateral margins of first three
segments squarish, of fourth and fifth segments rounded, and
of last two segments obtusely angulated behind. Legs all of
similar form, ambulatory, but increasing in length behind.

Abdomen composed of a single joint which is setose on the
margin and rounded behind with a small median excavation for
the reception of the uropods. Uropods scarcely projecting be-
yond the general outline of abdomen, biramous, with short
stumpy peduncle and outer ramus about one-half as large as inner.

Color very variable, commonly dark, slaty gray with dots or
small blotches of yellowish.

Length, according to Harger, extremely variable, females
frequently bearing eggs when less than half the length of speci-
mens figured which is about 7mm. The males are at least one-
third smaller than the females.

Distribution; North Sea; Baltic Sea; Greenland; Finland;
Denmark ; Scotiand; England; Bay of Fundy; Labrador; East-
port, Casco Bay, Maine; Gloucester, Provincetown, Massachu-
setts, Vineyard Sound; Noank Harbor, Stony Creek, New
Haven, Connecticut.

This species is quite active in its habits and is found crawling
over rocks and barnacles, and especially beneath rocks and drift
wood, often nearly up to high-water mark. It is sometimes
found in the burrows of Limnoria. It has been noted by
McMurrich to breed from the middle of June to the first week in
September.

It is distinguished readily from the other marine Isopoda of
Connecticut by the short uropods, arising from a notch at the
apex of the rounded abdomen and the multiarticulate flagellum of
the second antenne.

: BOPYROIDEA or EPICARIDEA.
First thoracic legs not cheliform ; uropods terminal, but some-
times pleopods and uropods are absent; when present pleopods

236 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. | Bull.

are exclusively branchial and not covered by an operculum.
Parasitic forms.

These are the most degraded forms of Isopoda; in some
instances the fully-grown female represents merely a simple sac
filled with ova, and without any trace of segmentation or of limbs.
In all cases the male is much smaller than the adult female and
is generally found clinging to the genital region of the female
like a parasite.

BOPY RIDA:

Body of female distinctly segmented and somewhat asymmet-
rical. Eyes, when present, dorsal.

Both pairs of antennz rudimentary.

Legs, seven pairs, sometimes obsolete on one side, all of
same structure, short prehensile. Coxal plates obsolete or distinct.
Marsupial plates five pairs; of which the first pair is made up of
two segments.

Abdomen more or less distinctly defined. Uropods, when
present, simple, lanceolate.

Male, symmetrical. Head rounded in front. Thoracic
segments distinct. Legs similar, prehensile. Segments of abdo-
men sometimes distinct, sometimes united.

Parasitic on decapods.

Stegophryxus hyptius Thompson.

1902. Stegophryxus hyptius, Thompson, Bull. U. S. Fish.
Com., vol. 21, p. 53-56, pls. 9, 10.

1905. Stegophryxus hyptius, Richardson, Bull. U. S. Nat.
Mus., No. 54, p. 532.

A species of Bopyrid which is parasitic on the gills of
Pagurus longicarpus (hermit crab), collected at Woods Hole,
Hadley Harbor, Naushon, Edgartown, Massachusetts, and War-
wick, Rhode Island.

Probopyrus pandalicola (Packard).

1881. Bopyrus palemoneticola, Packard, Zoology for High
Schools and Colleges, p. 288.

1905. Probopyrus pandalicola, Richardson, Bull. U. S. Nat.
Mus., No. 54, p. 554.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 237

The following description is from Miss Richardson’s Mono-
graph on the Isopods of North America.

“ Head deeply set in thorax; anterior margin straight ; poste-
rior margin rounded. Eyes wanting. Ovarian bosses present on
the first four segments of the thorax at the anterior part of the
sub-lateral margin; epimera evident as narrow plates lateral to
the ovarian bosses. The epimera occupy the entire lateral mar-
gins on the last three segments. The segments of the abdomen
are distinct. The terminal segment is broad, more or less bilobed.
The pleopoda consist of five pairs of double-branched lamellar
appendages, closely crowded together on the ventral side of the
abdomen.

“ The five pairs of incubatory lamelle surround a large open —
area normally filled with eggs. The first pair have the terminal
lobe of the distal segment large, well defined, and incurved.

“All the legs have a high quadrangularly shaped expansion or
carina on the basis. .

“ Male with all the segments of the thorax distinct, and with
the lateral margins contiguous. First four segments of the
abdomen well defined at the sides, but fused in the middle of the
dorsal surface. The last two segments form a single large piece,
the fused terminal segment being indicated only by a small median
point on the posterior margin. The body is a little more than
twice as long as wide. Eyes are present. The rudimentary
pleopoda are pairs of small oval processes, one pair on each
abdominal segment. The abdomen is about one and a half times
as broad as long.”

This species 1s parasitic on Palemonetes vulgaris (a prawn)
and has been reported from New Hampshire to Florida; East
Providence, Rhode Island; Acushnet River, Massachusetts ; Bald-
win Ledge, Mississippi; Brooklyn, New York.

ONTS COLDEA,

Body more or less depressed, oval or oblong in form, in some
cases capable of being rolled into a ball. Head generally small
and more or less sunk into first segment of thorax, no true
rostral projection.

First antennze always of very small size, never composed of
more than three segments, the last of these being often rudimen-

238 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

tary. Second antennz of normal structure and moderate length,
seldom exceeding half the length of the body.

Mouth parts adapted for biting. Mandibles without palp.
Maxillipeds not completely covering the other mouth parts and
with terminal parts more or less reduced.

Thorax composed of seven well defined quite similar segments,
the lateral parts of which are generally expanded to thin, forni-
cate plates.

Abdomen composed of six well defined segments.

_ Pleopods five pairs, which are respiratory in function; the
inner plate being of very delicate spongey structure whereas
the outer is more strongly ‘chitinized and covers the inner like
an operculum. Air cavities are sometimes present in this oper-
culum. Uropods biramous, with rami uniarticulate.

Oniscus asellus Linnzeus.

Fic. 76. Oniscus asellus.

1818. Oniscus affinis, Say, Jour. Acad. Nat. Sci. Phila., vol.
I, p. 430.

1841. Oniscus asellus, Gould, Invert., Mass., p. 336.

1899. Oniscus asellus, Sars, Crust. Norway, vol. 2, p. 171,
Pp. 75-

1905. Oniscus asellus, Richardson, Bull. U. S. Nat. Mus.,
No. 54, p. 600.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 239

1905. Oniscus asellus, Paulmier, Bull. N. Y. State Mus.,
Nos Or, p. 180:

Body oblong-ovate, about one and one-half times as long as
wide. Head twice as wide as long, with frontal margin slightly
convex, and pronounced antero-lateral lobes which are narrow-
and elongated and rounded anteriorly. Eyes large, compound,
oval, situated at sides of head at base of antero-lateral lobes.

First antennz very small and inconspicuous. Second pair
extending when retracted to posterior margin of third thoracic
segment, with first joint short; second and third subequal and
each twice as long as the preceding; fourth joint nearly twice as
long as third; and fifth joint one and a half times as long as
fourth; flagellum composed of three joints and shorter than last
peduncular joint.

Thoracic segments of subequal length; first one with antero-
lateral angles produced to embrace head, extending nearly to the
extremity of the antero-lateral angle of head. Coxal plates not
distinct but lateral margins of all the segments well expanded and
straight, producing an even contour. Legs moderately slender,
increasing in length posteriorly.

Abdomen not abruptly contracted; all the segments distinct,
the first two considerably shorter than the others and with their
lateral margins completely concealed by the last thoracic seg-
ment; lateral margins of third, fourth, and fifth segments ex-
panded, and produced and curved posteriorly to continue the
oval outline of the body, those of the fifth segment being produced
backwards strongly as far as the extremity of the last segment.
Terminal segment triangular with apex produced considerably
and pointed and convex above. Uropods rather produced, with.
the inner ramus originating far in front of the outer; peduncle
extending beyond the middle of last abdominal segment; inner
ramus narrow, linear, reaching as far as apex of abdomen;
outer ramus narrow lanceolate, extending beyond the apex.

Color, dorsal portion of body dark brown; lateral margins of
body and longitudinal rows of spots on either side at union of
coxal plates and body segments, light yellow.

Length 16 mm.

Distribution; Greenland; Iceland; Sweden; Norway; Den-
mark; Great Britain; France; Spain; Italy; Azores; also Woods

240 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Hole, Salem, and Beverly, Massachusetts ; New Haven, Connecti-
cut; Providence, Rhode Island; New York City, Schenectady,
New York: Rock Island, Illinois; Maine; Pennsylvania.

This species is found under dead logs, leaves, and stones and
is common in kothouses.

It may be recognized among the terrestrial Isopoda by the
even, rounded contour of the front and the pronounced antero-
lateral lobes of the head and the three joints of flagellum of
second antenna.

Philoscia vittata Say.

FES XY

= G :

ae et ie

Fic. 77. Philoscia vittata.

1818. Philoscia vittata, Say, Jour. Acad. Nat. Sci. Phila., vol.
ID ph 4 20.

1874. Philoscia vittata, Harger, Rept. U. S. Com. Fish. for
1871-2, p. 569.

1880. Philoscia vittata, Harger, ibid., for 1878, p. 306, pl.
a

1905. Philoscia vittata, Richardson, Bull. U. S. Nat. Mus.,
No. 54, p. 605.

Body oval, smooth, nearly three times as long as wide. Head
wider than long, with anterior margin rounded and antero-lateral
angles rounded and not produced to lobes. Eyes small, round,
compound, situated in antero-lateral angles of head.

I

bf

No. 26.] ARTHROSTRACA OF CONNECTICUT. 241

Antenne minutely hirsute, especially on the flagellum, extend-
ing to posterior margin of third thoracic segment; first segment
short ; second twice as long as: first; third segment as long as the
second, clavate; fourth nearly twice as long as the third; fifth
longer than fourth; flagellum composed of three nearly equal
joints ; the terminal one of which is tapering.

First thoracic segment longer than the succeeding ones which
are subequal ; anterior angles of first segment somewhat produced
at the sides to embrace the posterior part of the head; second and
third segments with their posterior angles less broadly rounded
but not produced backward at all;-fourth, fifth, and sixth seg-
ments with posterior angles increasingly produced toward the
posterior end and acute. Legs all ambulatory and increasing in
size and length to the last pair.

Abdomen abruptly narrower than the thorax, two-thirds as
wide as the last thoracic segment; first two segments with lateral
lamellz nearly concealed by the seventh segment of the thorax;
lateral lamelle of the three succeeding segments not large, acute.
Telson acute but not prolonged behind and not extending beyond
the end of the peduncle of the uropod which is broad. Uropods
with rami originating at the same distance from the base; outer
ramus narrowly lanceolate, tapering to the tip and exceeding by
less than one-half its length the more slender, styliform inner
ramus. e Bona

Color, dull and somewhat variable, usually brownish with light
lateral margins and narrow, median stripe separating the two
wide, dark bands.

Length 8 mm.

Distribution: Great Egg Harbor, New Jersey ; Freeport, Long
Island; Salem and Barnstable, Massachusetts; Vineyard Sound;
Stony Creek, Connecticut.

This species is found under rubbish me = Ones on the shore
below high-water mark. Say states that it is “very common
under stones, wood, etc., in moist situations.”

Cylisticus convexus (DeGeer).

1899. Cylisticus convexus, G. O. Sars, Crust. Norway, vol.
2p. 186; pl. SF.

16

242 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

1905. Cylisticus convexus, Richardson, Bull. U. S. Nat.

Mus., No. 54, p. 609. .
1905. Cylisticus convexus, Paulmier, Bull. N. Y. State Mus.,

No. 91, p. 181.

Fic. 78. Cylisticus convexus.

Body oblong-ovate, a little more than twice as long as wide,
dorsal surface strongly convex; able to contract into a ball like
an armadillo.

Head twice as broad as long with the antero-lateral angles
produced in large and rounded lobes; median lobe small and
triangular and with acute apex. Eyes small and compound,
situated at the bases of the antero-latéral lobes. ,

First pair of antennz inconspicuous, very small. Second
pair long and slender with flagellum composed of two sub-
equal joints; peduncular joints increasing in length distally.

Thoracic segments subequal in length; large coxal plates not
distinct from their segments ; those of first segment expanded to
embrace the head, extending to base of antero-lateral lobes as well
as posteriorly in acute processes; lateral margins straight. Legs
moderate, increasing in size posteriorly.

Abdomen with six distinct segments not abruptly contracted;
first two with lateral margins covered by last thoracic segment;
third, fourth, and fifth with lateral lamella prominent and curved
posteriorly to continue the even outline of the body. Telson tri-
angular, conically produced. Uropods considerably produced
beyond general outline of body, with peduncle extending a little
beyond the middle of apical process of telson; inner ramus origi-

No. 26.] ARTHROSTRACA OF CONNECTICUT. 243

nating far in front of outer one and extending as far as telson
while outer ramus extends more than half its length beyond the
abdomen.

Color light brown with longitudinal row of yellow spots on
either side marking union of coxal plates and segments ; also with
markings of yellow wavy lines between the median line and the
longitudinal rows of yellow spots.

Length 12.5 mm.

Distribution: Sweden; Norway; Denmark; Germany; British
Isles ; Holland; Belgium; France; and Turkey; also New Mexico;
Michigan; Lake Erie, Syracuse, Norwich, New York City, New
York; Ohio; Rock Island, Illinois ; Washington, District of
Columbia; New Haven, Connecticut.

This species is found in woods, under logs, along roads,
_ under stones, in woodsheds, usually in moderately dry places.

It may be distinguished from other terrestrial forms by the
great cohvexity of the body and its ability to roll up into a ball.
Armadillidium is the only other terrestrial form capable of roll-
ing into a ball but with this there can be no confusion because
of the pointed telson and prominent uropods of Cylisticus.

Porcellio spinicornis Say.

Fic. 79. Porcellio spinicorms,

1818. Porcellio spinicornis, Say, Jour. Acad. Nat. Sci. Phila.,
vol. 1, p. 431.

244 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

1899. Porcellio pictus, G. O. Sars, Crust. Norway, vol. 2,
p: 277, pl. 75, fig.-2.

1902. Porcellio spinicornis, Stoller, 54th Rept. N. Y. State
Mus., p. 213.

1905. Porcellio spinicornis, Richardson, Bull. U.S. Nat.

Mus., No. 54, p. 619.

1905. Porcellio spinicornis, Paulmier, Bull. N. Y. State Mus.,
No. QI, p. ;

Body oblong-oval, considerably depressed ; surface rough, with
less. dense tubercles than in P. scaber.

Head with very large lateral lobes which are slightly curved
outwards; frontal lobe less prominent, broadly rounded. Eyes
large, compound, situated at the base of the lateral lobes,

First pair of antennz inconspicuous. Second pair rather
slender and nearly one-half as long as body; second and third
peduncular joints with a carina on the outside which is pro-
duced to a dentiform projection; flagellum not as long as last
joint of peduncle, composed of two joints of which the proximal
is nearly twice as long as the distal one.

Coxal plates of thorax well developed with posterior corner
acuminate. Last pair of legs more strongly built in the male
than female, with carpus dilated. ;

Abdomen scarcely one-fourth as long as body; third to fifth
coxal plates prominent and recurved. Telson strongly produced,
one and a half times as long as broad at the base, terminal part
acute. QOpercular plates of only the first and second segments
of abdomen provided with air cavities. Uropods with rather
broad outer ramus.

Color, yellowish gray, variegated with dark brown patches,
generally arranged in five long series.

Length 13 mm.

Distribution ; Sweden ; Norway ; Denmark; Russia; Germany ;
France; Great Britain: ieteaneies also New Vouk Gia Niagara
Falls, New York; eon New Haven, Connecticut.

The species occurs in crevices of rocks and on shady lime-
stone ledges (Stoller) and also in damp cellars, etc.

It is distinguished from the two following species by the
spotted body and yellow color, and the flagellum of the second an-
tenne, the first joint of which is a little longer than the second.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 245

Porcellio scaber Latreille.

we Ns O72
—— Ss > =
Fic. 80. Porcellio scaber.

1818. Porcellio nigra, Say, Jour. Acad. Nat. Sci. Phila.,
vol. I, p. 432.

1853. Porcellio gemmulatus, Dana, U. S. Expl. Exped., vol.
14, p. 725, pl. 47.

1899. Porcellio scaber, G. O. Sars, Crust. Norway, vol. 2,
el 7On pl 77:

1902. Porcellio scaber, Stoller, 54th Rept. N. Y. State Mus.,
pe213:

1905. Porcellio scaber, Richardson, Bull. U. S. Nat. Mus.,
ING..54, p> 021. .

1905. Porcellio scaber, Paulmier, Bull. N. Y. State Mus.,
No: 91, p. 183.

Body oblong-oval, twice as long as broad; dorsal surface con-
vex and very rough with tubercles. Head with lateral lobes large
and rounded ; frontal lobe less prominent and obtusely triangular.
Eyes large and compound, placed at the base of the lateral lobes.

Second pair of antennz slender and scarcely one-half as
long as body; flagellum subequal in length to the last peduncular
joint and made up of two subequal joints.

Coxal plates of thorax moderate in size, with their posterior
corners acutely produced. Last pair of legs differing very little
in the two sexes.

Abdomen at least one-fourth as long as body; coxal plates of
third to fifth segments strongly recurved. Opercular plates of

246 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

only first and second segments provided with air cavities. Telson
rather strongly produced and terminating in an acute point. Uro-
pods longer than terminal segment, outer ramus broadly lanceo-
late and comparatively longer in male than female.

Color, uniform gray black, sometimes variegated with
irregular dark spots. P

Length 10 mm.

Disrtibution; world wide. British Columbia; Iceland; Cape
of Good Hope; Key West, Florida; also West Haven and
New Haven, Connecticut. . |

The species is found under logs and bark in generally dry
places, also under dead leaves and stumps and under boards, in
greenhouses. :

It is distinguished from the other species of the genus by
the unspotted body.

Porcellio rathkei Brandt.

Fic 81. Porcellio rathket.

1833. Porcellio rathkei, Brandt, Bull. soc. imp. Nat. Moscou.,
WOl0,>p.. 17 7.

1899. Porcellio rathkei, G. O. Sars, exe: Norway, vol. 2,
p. 180, pl. 79, fig. I.

1905. Porcellio rathkei, Richardson, Bull. U. S. Nat. Mus.,
No. 54, p. 622.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 247

1905. Porcellio rathkei, Paulmier, Bull. N. Y. State Mus.,
NG Ol, py 183,

Body oval, somewhat broader in female than male; dorsal
surface rather convex and slightly tuberculated. Head with
lateral lobes well developed, rounded; frontal lobe short, obtusely
triangular.

Second pair of antennz rather slender, nearly one-half as
long as body; flagellum about as long as last joint of peduncle
and made up of two joints of which the proximal one is shorter
than the terminal one.

Thorax with coxal plates moderate, subcontiguous, and with
posterior corners obtusely acuminate. Last pair of legs stronger
in male than female and with carpus remarkably dilated near the
base.

Abdomen scarcely one-fourth as long as whole body; third
to fifth coxal plates well developed and recurved. Opercular
plates all provided with air spaces. Telson subtriangular, with
outer part acutely produced and smooth above. Uropods with
outer rami broadly lanceolate and with the inner one extending
considerably beyond the last abdominal segment.

Color, variable.

Length 10 mm.

Distribution: Europe; Ohio; New York City; Lake Cham-
plain; Michigan; Maine; Massachusetts; Providence, Rhode
Island; New Haven, Connecticut ; Washington, District of Colum-
bia; Texas; Georgia. ¥

The species is very common under stones, boards, etc. It is
found very often in woodsheds and greenhouses.

It is distinguished from the other species’of the genus by its
white spots on a gray to black ground; and by the antero-lateral
lobes of the head which are smaller than in P. spinicornis.

Metoponorthus pruinosus (Brandt).

1899. Metoponorthus pruinosus, G. O. Sars, Crust. Norway,
wol.2).p:. 184; pl. do, fig. 2.

1902. Metoponorthus pruinosus, Stoller, 54th Rept. N. Y.
State Mus., p. 213.

1905. Metoponorthus pruinosus, Richardson, Bull. U.S. Nat.
Mus., No. 54, p. 627.

248 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

1905. Metoponorthus pruinosus, Paulmier, Bull. N. Y. State
Mus., No. 91, p. 183.

Fic. 82. Metoponorthus pruinosus.

Body oblong-ovate, twice as long as wide. Head twice as
wide as long, with anterior margin slightly convex and antero-
lateral lobes small. Eyes small, composite, situated at base of
antero-lateral lobes.

First pair of antennz small and inconspicuous. Second pair
with first joint short ; second and third each twice as long as first ;
fourth twice as long as third; and fifth one and a half times
as long as preceding; flagellum composed of two joints, the first
of which is twice as long as the second and, taken together,
almost as long as fifth peduncular joint; whole appendage ex-
tending as far as posterior margin of fourth thoracic segment.

First segment of thorax a little longer than any of the others
which are subequal. Antero-lateral angles of first segment pro-
duced forward to surround the head and extending to base of
antero-lateral lobes of head. Epimera not distinctly separated
from the segments. \

Abdomen abruptly narrower than thorax. All six segments
distinct ; first two covered laterally by the last thoracic; third,
fourth, and fifth segments with lateral parts not greatly expanded;
sixth segment triangular in form and half as long as wide at

No. 26.] ARTHROSTRACA OF CONNECTICUT. 249

the base, apex acute and with slight concavity in its dorsal
surface.

Uropods with peduncle not extending as far as apex of last
abdominal segment ; outer ramus lanceolate and more than twice
as long as last segment of abdomen; inner ramus about one-third
as long as outer one.

Color, posterior and lateral margins of uniform reddish
brown; other parts of a lighter color. Surface of body slightly
granulated.

Length 9 mm.

Distribution: Ohio; Kansas; California; Utah; New Mexico;
Texas; Florida; Washington, District of Columbia; Virginia;
Maryland; New York City; Massachusetts; West Indies; Ber-
muda; Bahamas; Europe; North Africa; Venezuela.

The species is found under logs and decaying vegetable
matter, in greenhouses, along walls, and in dwellings.

It may be distinguished from other terrestrial forms by the
fact that the abdomen is abruptly narrower than the thorax.

Actoniscus ellipticus Harger.

a)

Fic, 83. Actoniscus ellipticus.

1878. Actoniscus ellipticus, Harger, Amer. Jour. Sci., ser. 3,
Voll 5, p!)373.

1905. Actoniscus ellipticus, Richardson, Bull. U. S. Nat.
fOr 1675, p. 200; ‘pli a, fig, 3)"

250 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

1905. Actoniscus ellipticus, Richardson, Bull. U. S. Nat.
Mus., No. 54, p. 634.

Body rather broadly oval and depressed, twice as long as
wide. Head broader in front than behind with antero-lateral
angles produced in broad, diverging, rounded lobes, angularly
produced in middle line beyond lateral lobes. Eyes small, black,
oval, situated at sides of median triangular process.

Antenne with first joint short; second joint enlarged distally,
especially on inner side; third joint scarcely as long as second,
clavate, and articulated at an angle with the preceding one; |
fourth joint longer than third; fifth still longer, slender, slightly
bent at the base and so forming an angle with the fourth; flagel-
lum shorter than last joint of peduncle, composed of four joints
of which the second and the third are longer than the first which
in turn is longer than the fourth; terminal segment showing
indications of another rudimentary segment and tipped with
sete.

First thoracic segment excavated in front for the accommoda-
tion of the head; succeeding segments subequal to the seventh
which is the shortest; first segment prolonged laterally to about
twice its length on the mid-dorsal line; the second and in an
increasing degree, the succeeding segments, produced backwards
at the sides. Legs rather small and weak and of uniform size,
ambulatory. .

Abdomen with first two segments having their lateral lamellz
obsolete and concealed by the seventh thoracic segment; third,
fourth, and fifth segments produced laterally into broad plates
which are curved backwards, and whose margins continue the
even contour of the thorax; last segment not as long as wide,
rounded posteriorly. Uropods terminal with peduncles which are
expanded so that they continue the contour of the body and are
larger than the expansions of the fifth segment; ramus styliform
and tipped with sete; inner pair arising from near the base of
the peduncles and extending very slightly beyond the outer ones
which arise from a notch near the middle of the inner margin

of the peduncle and surpass slightly the expanded lobe of the
peduncle.

Color, slaty gray.
Length 4 mm.

No. 26.] ARTHROSTRACA OF CONNECTICUT, 251

This species has been found at Savin Rock, near New Haven,
and Stony Creek, Connecticut, in company with Philoscia vittata
Say, by Professor Verrill.

ARMADILLIDID.

Body convex, contractile into a ball.

Antenne comparatively small, with flagellum bi-or triarticu-
late.

Head flanked by side plates of first thoracic segment, front
margin subtruncate, lateral lobes distinct; median lobe obsolete ;
epistome vertical. Mouth parts similar in structure to those of
the Oniscide.

Legs comparatively short and uniform in structure, ambula-
tory.

Abdomen not abruptly contracted. Terminal segment short
and broad. Opercular plates of first two pairs of pleopods, or of
all five pairs, provided with air spaces. Uropods short, not ex-
tending beyond the limits of the last segment and lateral plates
of the fifth segment.

Armadillidium vulgare (Latreille).

Fic. 84. Armadillidium vulgare.

1818. Armadillo pitularis, Say, Jour. Acad. Nat. Sci. Phila.,
vol. I, p. 432.

1841. Armadillo pitularis, Gould, Invert. Mass., p. 336.

1899. Armadillidium vulgare, G. O. Sars, Crust. Norway,
vol. 2, p. 189, pl. 82.

252 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

1905. Armadillidium vulgare, Richardson, Bull. U.S. Nate
Mus., No. 54, p. 666.

1905. Armadillidium vulgare, Paulmier, Bull. N. Y. State
Mus., No. 91, p. 184.

Body oblong-ovate with lateral margins subparallel, rather
convex and able to be rolled up into a ball; twice as long as wide;
abdomen one-fifth the length of the body. Head much wider
than long, transversely truncated in front with lateral lobes small
and rounded. Eyes small, round, compound, and _ situated
laterally.

First antenne rudimentary and inconspicuous. Second pair
one-fourth as long as body; second joint four times as long as
first; third joint one-half as long as second and shorter than
the fourth joint which is one-half as long as the fifth; flagellum
as long as: fifth joint, composed of two joints of which the first
is the shorter.

Thoracic segments subequal, coxal plates not distinct, those of
the first segment with posterior angle acute. Last pair of legs
with ischium large but not, in accordance with Sars’s description,
as long as the succeeding joints. <a

Abdomen semicircular, as wide as thorax; first two segments
covered at the sides by the seventh thoracic segment. Last seg-
ment much shorter than wide at the base, slightly tapering distally,
tip transversely truncated. Uropods not longer than terminal
segment of abdomen; outer ramus much shorter than peduncle,
which is not visible from above, and very broad; inner ramus
narrow and elongate, not extending beyond extremity of abdomen.

Color, sometimes uniformly dark grey or nearly black, some-
times variegated with lighter patches.

Length 16 mm,

Distribution: world wide; Algeria; Azores; Bermuda;
Louisiana; Texas; Mississippi; Kentucky; Washington, Dis-
trict of Columbia; South Carolina; New York; Long Island;
Ohio; Massachusetts; Rhode Island; New Haven, Connecticut.

This species is found under stones; in cellars; under boards
in damp soil; in hothouses. It is injurious to some plants grown

in greenhouses as well as to young cotton and mushrooms in
Louisiana and Texas,

=

No. 26.] ARTHROSTRACA OF CONNECTICUT. 253

It can be distinguished from other terrestrial forms by the
short uropods which do not project behind the telson which is
truncate.

SCY PHACIDZA:.

Head without median or antero-lateral lobes. Front not
margined but continuous with the epistome.

Second pair of antenne with flagellum composed of four
joints.

Mandibles without molar tubercle. First maxilla with inner
lobe furnished with two plumose sete; outer lobe furnished with
teeth. Maxillipeds with masticatory lobe acutely produced; palp
elongate.

Abdomen not abruptly contracted. Uropods extending beyond
tip of abdomen; inner ramus inserted at upper inner margin of
peduncle.

Scyphacella arenicola Smith.

1874. Scyphacella arenicola, Smith, Rept. U. S. Com. Fish.
for 1871-2,.p. 568.

1880.. Scyphacella arenicola, Harger, ibid., for 1878, p. 307,
pl. lise Dee

1905. Scyphacella arenicola, Richardson, Bull. U. S. Nat.
Mus., No. 54, p. 671.

As I have not met with this species myself I quote Professor
Smith’s original description :

“ Body elliptical; abdomen not abruptly narrower than the
thorax; the whole dorsal surface, except the extremity of the
abdomen, covered with small, depressed tubercles which give
rise to minute spinules; eyes prominent, round; antenna a little
longer than the breadth of the body; first and second segments
short, equal; third, fourth, and fifth successively longer, the fifth
being rather longer than the terminal portion, which is more
slender than the fifth segment, tapers regularly to the tip, and
is composed of three successively much shorter segments, and a
very short somewhat spiniform, but obtuse, terminal one; all
the segments, except the minute terminal one, scatteringly beset
with spinules; legs beset with small spines; the ischial, meral,
carpal, and propodal segments subequal; terminal process of the
last segment of the abdomen narrow, triangular, with the apex

254 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

slightly rounded, and the dorsal surface a little concave; posterior
caudal appendages much shorter than the abdomen ;-rami slightly
tinequal, the outer stout, spinulose; the inner a little shorter and
much more slender.”

Color, in life, nearly white, with chalky white spots and
scattered, blackish dots arranged irregularly; in specimens pre-
served in alcohol, dark brown, with the margins of the segments
of a lighter brown.

Length 3-4 mm.

Distribution: Great Egg Harbor, New Jersey; mouth of
Choptauk River, Maryland; Vineyard Sound, Woods Hole,
Massachusetts ; Nantucket. The species has not yet been reported
from Connecticut waters, but may be expected inasmuch as it
occurs both to the north and south, e

According to Professor Smith, it burrows in the sand of
beaches just above ordinary high-water mark.

Fig.
Fig.

Fig.
Fig.
Fig.
Fig.
Fig.

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.
Fig.

S

LIST OF“ EIGURES

Details of head and mouth parts in situ of

Orelestiar cretlis (22 tence epee ae he Sb) ebeyecgs «re
Internal anatomy of an ideal Gammarid, after

Shaslol ube ee ee Be Gin ae parece
Ideal cross section of a female Gammarid......
Pymeria-calbas (Montage i cciamslsese's te «6 3--
ey SiAMOpsis alibar Fi Olmtesiy cleat ete sheticrstecartis (s,4 >
dimetonyoe quadtratus Spr MOVns: ois steal mire 2200p:
Orchomenella pinguis (Boeck), habitus figure

HOt A SALSA Prdhatta ae er eolage Shae aided 6. one
Ampelisca macrocephala Lilljeborg, after Sars
Ampelisca spinipes Boeck, after Sars... 02...
yblsssechaka Smite. 2 Wet tela heed seo ide wis < okec!
Haustorius arenarius (Slabber), after Sars....
Phoxocephalus holbolli (Kroyer), after Sars...
Paraphoxius spinosus’ Holmes es 25 3.) 03.0. os
SlEMOEMOGI CY MMS. OlMES ne Sats eo Ste's wale Were dence
Stenothioe imuimuta sfolmese! 22) Sus 65 Sees
Sympleustes glaber (Boeck), after Sars......
Calliopius leviusculus (Kroyer), habitus figure

I eh iW Cias Peo Raed Cre icicg Aa a Os mre Uo au en
Batéarsecundaelolmesivs. Aqaa.% has eseeot si.
Pontogeneia inermis (Kroyer), after Sars....
Crane onyx word ctliste( Stith)". el, «bets ove Se
CLAN COMye LEMMISPSIMNIElye rs ciel ogi cre tuts alert
heli artaiticas Smith 52 Gee ee ccd teres
Melita dentata (Kroyer), after Sars.2.. 2.02.
Blasmopis levis: (Smith )ie.. ea cha sect. 2
Dikerdsammarus fasciatus (Say)... 2 .s..8 6.
Gammarus locusta (Linneus), habitus figure

PUTS) Sareea Ne CR UR eR ge a

255

CONNECTICUT GEOL. AND NAT. HIST. SURVEY.

Carinogammarus mucronatus (Say), habitus

figure after Paulmier..........+.eseseeeee
Dexamine thea Boeck. . 05... iy diet > ome ereeieme
Orchestia agilis Smith. The upper right hand

drawing shows the sperm duct when enlarged

at the breeditig seasom: « . 2...) j-.-)-15 eee
Orchestia palustris Smith.: .. 43.26. --s eter
Talorchestia longicornis (Say): <...: 2) ermine
Talorchestia megalophthalma (Bate) .........
Hyale prevostii (Milne-Edwards), habitus figure

after Sars2 3s. i'd.s.ottues wore ohana ana
Hyalella knickerbockeri (Bate), after Smith...
Allorchestes littoralis Stimpson, after Paulmier
Microdeutopus gryllotalpa Costa, after Sars....
Lembos’ smithi (Eiolnves:) ; sv. serge ee ere
Photis: reinbardit Kroyere, cvs sicle stteitet eee

Podoceropsis nitida (Stimpson), after Sars.... |

Leptocheirus pinguis (Stimpson)..........+..
Amiphithoe longimana Smith... 2): sp. cigseeer
Amphithoe rubricata (Montagu), after Sars...
Grubia compta (Smuith)\ 0.8) aes eee eee
Jassa marmorata Holmes, after Paulmier......
Ischyrocerus anguipes Kroyer, habitus figure

alter Sars. 5, Gc nvts)s Sea ee

Cerapus tubularis Say, after Smith)... .°12 223.

Ericthonius brasiliensis (Dana), after Sars....
Unsiola,irrorata: Say... Jini eee «aie See
Siphoneecetes smithianus, Rathbun... /).. s2eee
Corophium cylindricum (Say) seinen eee
4eginella longicornis’ \(Kroyer).:../.5. 7.2
Caprella linearis: (Minnzeus))s. 7... «coat oe eee
Caprella geometrica Say: ..°.53 26005 «9 eee
Tanais cavolinii Milne-Edwards, after Sars....
Leptochelia savignyi (Kroyer), after Harger..
Cyathura carinata (Kroyer), after Harger.....
Ptilanthura tenuis Harger, after Harger......
Cirolana concharum (Stimpson), after Harger
/Ega psora (Linnzus), after Harger..........
fEgathoa oculata (Say), after Harger........

[ Bull.
Page.

II4
116

11g
121
123
125

127
129
131
134
137
140
142
145
148
150
152
155

157
160 |
164
166
169
172
175
177
179
194
195
199
201
203
205
208

No.

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Big.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.
Fig.

ARTHROSTRACA OF CONNECTICUT.

Mivonceas ovalis (Say )evatter \Smaith.). otc. oa.
Limnoria lignorum (Rathke), after Harger....
Spheroma quadridentatum Say, after Harger..
Whinidoteavececay (Say) satter larger... 5. .'.6%
Chiridotea tuftsii (Stimpson), after Harger....
Idothear balticah(Pallas) patter, Plareer. 5... ..
Idothea phosphorea (Harger), after Harger. ee
Edotea triloba (Say), after Harger..........
Edotea montosa (Stimpson), after Harger.....
Frichsonella attenuata (Harger), after Harger
Erichsonella filiformis (Say), after Harger....
ASellue: communis Say, ater Snaith si.) 2...
eeratinarina ((Pabricius)),atter Sats... .....
Oniscus asellus Linnzus, after Paulmier......
Philoseia, vittatay oay,-atter Elargete 500). 0s,
Cylisticus convexus (DeGeer), after Paulmier
Poscellio spimicornis Say, after Sars. ..3........
Porcellio scaber Latreille, aiter Sars... ..... o>
Porcellio rathkei Brandt, after Paulmier......
Metoponorthus pruinosus (Brandt), after Paul-

IDSC Coches Secon ohare Ean ea eee
Actoniscus ellipticus Harger, after Harger....
Armadillidium vulgare (Latreille), after Paul-

BIBLIOGRAPHY

Bate, C. S. On the British Edriophthalma. Rept. British Soc.
for Advance. of Science, 1855, pp. 18-62,
pl. 12-22, 1856.

Catalogue of the Amphipodous Crustacea in fe
British Museum, pp. 399, pl. 58, 1862.

Bate, C. S. and Westwood, J. O. A History of the British
Sessile-eyed Crustacea. 2 vols., pp. 507, 530,
1868. :

Bovallius, C. Contributions to a Monograph of the Am-
phipoda Hypertidea. Kongliga Svenska. Vet-
enskaps Akademiens Handlingar, Ny Foljd.
bd. 21) no. 5s PP. 72, pls. 10, and: Bd Zaymer
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Della Valle, A. Gammarini. ee u. Flora des Golfes von
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Harger, O. Notes on New Engl nae Isopoda. - Proc.“ Waass
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Report on the eee aeons of New England.
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pls. 1-13. 1880.

Holmes, S. J. Observations on the Habits and Natural His-
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Synopses of North American Invertebrates,
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The Amphipoda of Southern New England.
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Descriptions of Three Species of Sand Fleas
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Mus., vol. 18, pp. 593-603. 1896.
258

Judd, S. D.

No. 26.] ARTHROSTRACA OF CONNECTICUT. 259

Kroyer, H. Gronlands Amphipoder. Det Kongelige Danske
Videnskabernes Selskabs naturv. og math.
Afhandlinger, Afh. 7, pp. 229-326. 1838.
Copenhagen.
Kunkel, B. W. The Amphipoda of Bermuda. Trans. Conn.
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Leidig, F. Ueber Amphipoden und Isopoden. Zeitsch. f.
wissen. Zool., Bd. 30 (suppl.), pp. 225-274,
plsh"@-125-18738:
es P. Caprelliden. Fauna u. Flora des Golfes von Neapel,
Monogr. 6, p. 201, pls. 10. 1882.
Nachtrag zu den Caprelliden, ibid., Monogr.
I 72 PP.us5, pissy. LSGO:
Paulmier, F.C. Higher Crustacea of New York City. Bull.
New York) State: Museum, no. 91; pp.
118-189. 1905.
Rathbun, Mary J. List of the Crustacea, Fauna of New Eng-
land, no. 5. Occasional Papers, Boston So-
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1905.
Richardson, Harriet . Synopses of North American Inverte-
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Key to the Isopods of the Atlantic Coast of
North America. Proc. U. S. Nat. Mus., vol.
23, PP. 493-579. I90T.
Contributions to the Natural History of the
Isopoda. ibid., vol. 27, pp. 1-31. 1904.
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Say, Thomas An account of the Crustacea of the United
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PP. 374-401, 323-433. 1818.

260 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull.

Smallwood, M. E. The Beach Flea, Talorchestia longicornis.
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eae (or

The Salt-marsh Amphipod, Orchestia palus-
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Smith, S. I. Crustacea of the Fresh Waters of the United
States. Rept. U. S. Com. Fish. for 1672-3)
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Occurrence of Chelura terebrans, a Crust-
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Structures, on the Coast of the United
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On the Amphipodous Genera Cerapus, Un-
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Smith, S. I. and Verrill, A. E. Notice of the Invertebrata
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U. 5S. Lake Survey." Amer. Jour. Sc isemee
vol. 2, pp. 448-454. 1871.

Smith, § I. and Harger, O. Report on the Dredgings in the
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pls. 1-8. 1874.

Spencer, W. B. The Urinary Organs of the Amphipoda.
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Stebbing, T. R. R. The Amphipoda. “ Challenger” Reports,
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A History of Crustacea. Recent Mala-
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Stimpson, Wm. Synopsis of the Marine Invertebrata of
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Non 26. ARTHROSTRACA OF CONNECTICUT. 261

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