266. A HISTORY OF RECENT CRUSTACEA 
dibles (short), both the latter being biramous and natatory 3 
(2) a second Nauplius stage, in which maxille and maxilli- 
peds appear as bud-like rudiments; (8) Metanauplius, with 
the carapace commencing, and the mandibular legs lost; 
(4) Calyptopis, with body divided into two regions, and 
much other development, but eyes not mobile, and no trace 
of legs or pleopods ; (5) an unnamed intermediate stage, 
in which the eyes become stalked and mobile; (6) Furcilia, 
with the compound eyes more fully developed, and the 
anterior legs and pleopods taking form; (7) Cyrtopia, 
in which the flagellum of the first antennze becomes 
elongate and distinctly articulate, so that these appen- 
dages cease to serve the purposes of locomotion. ‘in 
their metamorphosis,’ the authors say, ‘the Huphau- 
slide stand almost alone, and none of the later larval 
stages are identical with the Zoea and other larvee of Deca- 
pods. They commence their larval life in the Nauplius con- 
dition, a type of larva frequent in other groups, particularly 
among the Copepods, Cirripedes, some Decapods, and vari- 
ous parasitic forms. The larval function of the antennv is 
retained until the commencement of the Cyrtopia stage, 
a feature which is not usual among the Crustacea. The 
Calyptopis stage, in which the compound eyes, while 
undergoing development, are covered by an anterior ex- 
pansion of the carapace, is a remarkable one, which, so far 
as we know, is only met with in one other group, an 
aberrant section of the Decapcds, including Lucifer, &c., 
where this condition obtains in the Protozoea stage.’ The 
names of the so-called Calyptopis, Furcilia, and Cyrtopia 
stages have been adopted from three supposed genera, 
established by Dana, who assigned the first two to the 
Mysidze, and the third to the Euphausiide, all of them, in 
fact, representing stages in the development of the latter 
family. 
Fumily 4.—Myside. 
The carapace is generally rather small, loosely covering 
the trunk behind, of which the segments are distinctly 
defined, though narrow and crowded dorsally. The first 
