PACKARD.] ANATOMY OF NEBALIA. 433 
its fossil allies (see Bibliography), and gave a description of the order 
and mentioned the types composing it. 
Nearly a year later, in 1880, Claus, in the last edition of his Zoology, 
according to Carus’ Yahresbericht, 1880, also suggested that Nebaha 
represented a distinct order, which he calls Leptostraca. We have not 
seen the last (fourth) edition of Claus’ Zoology (1882), in which the or- 
der is noticed. 
Habits.—The species of Nebalia inhabit the sea at moderate depths. 
We have dredged WN. bipes on the coast of Labrador in from four to 
eight fathoms, and on the coast of Puget Sound we collected a sim- 
ilar species, just below low-water mark, among fucoids. The fol- 
lowing is taken from Baird’s British Entomostraca: *‘Otho Fabricius 
tells us that it carries its eggs under the thorax during the whole 
winter; that they begin to hatch in the month of April, and that the 
young are bornin May. They are very lively, he adds, and adhere to the 
mother, who appears then to be half dead. The adult swims in a prone 
state, using its hinder feet to propel it through the water. They are 
not very active. Montagu informs us that when moving in the water 
the superior antenne are in constant motion as well as the abdominal 
feet, but that the inferior antenne are usually motionless and brought 
under the body. They are found, according to Leach, on the south- 
western and western coasts of England, under stones that lie in the mud, 
amongst the hollows of the rocks; and Mr. McAndrew dredged it from 
a considerable depth amongst the Shetland Isles.” 
1.—THE ANATOMY AND DEVELOPMENT OF NEBALIA. 
The first published description of the present species was by Kroyer, 
in his Naturhistorisk Tidskrift (Ser. 2, Bd. 2). It is written in Danish, 
and not accompanied by any figures. " 
In Nebalia bipes the body is rather slender and somewhat compressed, 
the anterior half protected by a carapace, beyond the lower edge of 
which the broad thin phyllopodiform feet do not project. 
The carapace.—The head and anterior half of the body, including the 
thorax and four anterior abdominal segments, are covered by the cara- 
pace, which on the lower edge extends below the ends of the thoracic 
feet, covers the basal joints of the antennz, and entirely covers the 
mouth parts. The sides are compressed, and are drawn together over 
the body by a large but rather weak adductor muscle (Pl. XXX VII, 
fig. 6), situated a little in front of the middle of the thorax. There is no 
large highly specialized adductor muscle connecting the two sides of the 
carapace, nor any well-marked round muscular impression in the cara- 
pace, such as is characteristic in the Estheriade ; nor is there any hinge, 
a still more characteristic feature in the bivalved Phyllopods. On the 
contrary, aS seen in Pl. XXXVI, fig. 3, representing the carapace re- 
moved from the body and flattened out, there are no signs of a median 
hinge-joint. 
The nature of the rostrum is one of the diagnostic features of this 
order. In WNebalia, the rostrum is long and narrow, oval, seen from 
above, terminating in an obtuse point quite far in advance of the head. 
It is loosely attached to the sinus in the front of the carapace, and thus 
forms a long, narrow, tongue-like flap, with a free movement up and 
down. It is thus seen to be rather a movable appendage of the cara- 
pace than a solid, immovable continuation of it, as in the Decapoda. 
Upon removing the carapace and flattening it out, it is seen to be 
readily comparable with the carapace of Ceratiocaris. 
28 H 
