MACRURA ANOMALA 149 
TRIBE I.—ANOMALA. 
The pterygostomian regions are free from the epistome 
and marked off from the back by a suture or continuous 
furrow. The fifth pair of legs are generally weak, not fit 
either for walking, swimming, or grasping food and prey. 
The tribe embraces five legions, Hippinea, Lithodinea, 
Pagurinea, Porcellaninea, Galatheinea. 
Legion 1.—Hippinea. 
The carapace is ovate or subquadrate, comparatively 
smooth, the regions ill defined, the ‘ front’ broad. The 
cornese of the eyes are small. The first antennz are in 
general strongly developed, with one flagellum elongate, 
the other of moderate size or absent. The second antennz 
have usually a short flagellum and a massive peduncle of 
four or five joints, with or without a movable acicle on 
the second. The third maxillipeds are moderately broad, 
sub-operculiform. The walking-legs have a_ flattened 
terminal joint. The fifth pair are slender and filiform and 
folded under the preceding pair. The sterna of the trunk 
are linear. The pleon is partially extended, with the tel- 
son large, longer than broad, and the preceding segment 
carrying a pair of biramous lamellar appendages, not so 
arranged as to form a rhipidura. The males have no 
appendages to the pleon but those of the penultimate 
segment. 
The members of this legion inhabit the shallow waters 
of tropical and subtropical seas. They are divided between 
the two families of the Hippidee and Albuneidee. 
Family 1.—Hippide. 
The third maxillipeds are sub-operculiform, with a brcad 
fourth joint; the exopod is wanting. The first pair of legs 
are sub-cylindrical and not chelate. The telson is elongate, 
lanceolate. 
This family includes three genera. 
Hippa, Fabricius, 1793, has been much restricted since 
it was first instituted. It is now especially distinguished 
