74: ZOOLOGICAL EXERCISES. 
nal antennee are larger, and lie between the front and 
the orbit; the basal joints are large, and firmly 
attached to the carapace. 
2. Ascertain the name of the crab by means of the fol- 
lowing analysis, which includes only the eight species 
most common on the shores of New Zealand :— 
Sub-Tribe Cyclometopa.—Carapace arched in front. Fourth 
joint of the external maxillipedes inserted at the summit or 
the antero-internal angle of the third joint. Male genital 
appendages at the base of the fifth pair of legs. 
FAMILY Cancrid#,—All the tarsi styliform. 
GENUS Cancer.—External maxillipedes long, the third joint 
rounded. 
Cancer novezcalandie.—Latero-anterior margins of the 
carapace with ten crenated lobes. Front with 
three teeth. 
GENUS Heterozius.—Third joint of the external maxillipedes 
very small, and narrowed anteriorly. 
Heterozius rotundifrons.—Latero-anterior margins en- 
tire. Front narrow, prominent, rounded in the 
middle, where it is divided by a narrow fissure of 
little depth. 
Sub-Tribe Catometopa. — Carapace sub-quadrate. Fourth 
joint of the external maxillipedes inserted at the summit, 
or at the antero-external angle of the third joint, Male 
genital appendages in the sternum, near the basal joints of 
the fifth pair of legs. 
FAMILY Macropthalmide.— Eye peduncles long, not less 
than one-third the width of the carapace. 
Genus Hemiplax.—Front nearly one-third the breadth of the 
carapace. Anterior legs sub-equal. 
Hemiplax hirtipes—Antero-lateral margin of the cara- 
pace with three teeth; the first strong, the two 
others smaller, acute. 
FAMILY Grapsidez.—Hye peduncles short, not equal in length 
to one-third of the width of the carapace. 
GzeNus Heterograpsus.—Internal antennz concealed by the 
front. No oblique hairy crest on the third joint of the 
