G r.ADOCEBA. CRU STAGE A. Ruici loi'oi>a. 
291 
and thus adapted more for respiration than locomotion. 
The body is usually divided into numerous segments. 
This order contains the largest individuals of all the 
Entomostraca, and many of them the most remark- 
able for beauty. As an illustration of the order, we 
have annexed a figure of Chiroceplialus diaphanm . — 
See fig. 192. 
motion through the water is peculiar, being a tumbling, 
Fig. 193. 
Order II.— CLADOCERA. 
The species of this order are generally very 
small and have the body, with the exception of 
the head, contained within a delicate trans- 
parent carapace, formed in the shape of two 
valves joined together on the back. They 
possess from four to six foliaceous branchial 
feet, have only one eye, and two pairs of 
antennae, the lower of which are the organs of 
motion. 
The species here represented (fig. 193) is 
Daphnia Schcefferi. 
There are seven known British species; that figured 
is by far the largest of the family, being about the 
lifth of an inch in length, and two lines broad. Their 
Daphnia SchfeATcH. 
heavy sort of movement, and when seen in their native 
ponds they seem to keep near the bottom. 
Section II. — LOPHYROPODA 
The Lopltyropods are characterized by their feet being 
essentially organs of locomotion, and not branchials. 
Fig. 194. Fig. 195. 
Cypridina M'Andrei. Cyclops quadricornis. 
These are few in number, and are composed of several 
articulations of a more or less cylindrical form, which 
are furnished with a series of stiff hairs or setce. Their 
branchiae or gills are attached to the organs of the mouth 
and are few in number. The body is either completely 
inclosed within a carapace exactly resembling a bivalve 
shell, or partially covered by an envelope shaped like a 
shield or buckler. The two forms constitute two orders, 
OsTRACODA and Copepoda. 
The first order, or Ontracods, we illustrate by a figure 
of Cypridina M"- Andrei (fig. 194) ; tlie second (the 
Cope.pods) by Cyclops quadricornis (fig. 195). 
Very little is known of the habits and manners of 
these interesting and curious little creatures ; the two 
species which have been found in Great Britain belong- 
ing to this genus were dredged by Mr. M'Andrew 
from a considerable depth. Cypridina M‘ Andrei was 
dredged in seventy fathoms, between the islands of 
Lewis and Skye. Other species, C. Bronda, was 
found in from eighty to ninety fathoms sand, twenty 
miles east of the Noss, in the Shetland Islands. 
Section III. — PCECILOPODA (Parasitic Crustacea). 
The animals belonging to this section have the organs 
of the mouth adapted for suction, and not mastication. 
They live a parasitic life upon aquatic animals, such as 
fishes, &c. ; and their mouth therefore is constructed so 
as to accommodate them to their habitations and man- 
ner of life. Their body is for the greater part inclosed 
within a buckler-shaped shell or carapace of a horny 
substance ; and tbeir feet, which are in the greater num- 
ber, four pairs, are partly adapted for enabling them to 
walk with, and partly serve for the purpose of respira- 
tion, having branchiae or gills attached to them. When 
young they are free and unattached, and do not resem- 
ble in the least their parents. As they advance in life 
they undergo a series of changes, and become attached 
to various other animals. Man}”^ of them at last become 
so transformed that they lose their eyes and feet, and 
