256 A HISTORY OF RECENT CRUSTACEA 
CHAPTER XVIII 
SUB-ORDER IlI.—SCHIZOPODA 
THE mandibles have generally an elongate ‘palp.’ The 
second and third maxillipeds are similar in general struc- 
ture and function to the series of trunk-legs, the whole 
seven pairs of appendages, and in general the first maxilli- 
peds also, being provided with well-developed exopods or 
swimming-branches. There are no chelipeds. The ova 
are carried by the female beneath the trunk, either with 
or without the protection of marsupial plates, and gene- 
rally one or two of the larval stages are passed through 
before the hatching of the young animal. The males are 
generally distinguished by a special appendage on the first 
antenne and by larger pleopods. 
The name Schizopoda, ‘ cleft-footed, refers to the 
double character borne by so many of the appendages, in 
which the main stem or endopod is more or less ambulatory 
and the exopod is adapted for swimming. The affinity 
which the Schizopoda show to some of the Macrura, such as 
the Pasipheide, and the definite opinion of Mr. Spence 
Bate that they ought to be included as an aberrant group 
among the Macrura dendrobranchiata, have been already 
noticed. Whether they should stand just inside or just 
outside the sub-order of the Macrura, is a nice point of 
classification for the learned to decide. 
Four families are at present included in the Schizopoda, 
the Lophogastride, Eucopide, Euphausiide, and My- 
side. But on the one hand a suggestion has been made 
that two forms hitherto assigned to the Mysidae may re- 
quire the institution of a separate family, and on the other 
hand Mr. G. M. Thomson, the well-known naturalist of 
