104 A HISTORY OF RECENT CRUSTACEA 
CHAPTER VIII 
TRIBE IIl.—OXYRRHYNCHA 
THE carapace is more or less narrowed anteriorly and 
usually rostrate, with the hepatic regions small, the bran- 
chial large. The epistome is generally large. The buccal 
frame is quadrate, with the anterior margin straight. 
There are nine pairs of branchiz, with the efferent chan- 
nels opening at the sides of the endostome. In this, 
as in the two. preceding tribes, the afferent channels 
open behind the pterygostomian regions, in front of the 
base of the chelipeds. The first antennz are longitu- 
dinally folded. The third maxillipeds have the fifth joint 
articulated at the apex or at the front inner angle of the 
fourth. The verges of the male are exserted through 
the bases of the last pair of walking legs. 
This tribe of the ‘sharp-snouted’ crabs is divided 
into two legions, the Maiinea and Parthenopinea. It has 
been observed in many cases that the two halves of the 
large liver are not separate, but united by a median lobe. 
The nervous system is said to attain a higher degree of cen- 
tralisation in this group of Crustacea than in any other, the 
ganglia of the trunk forming a single solid disk-like mass. 
Legion 1.—Maiinea. 
The basal joint of the second antennz is well de- 
veloped, inserted beneath the eyes, and usually occupies a 
great part of the infra-ocular space. 
This legion contains three families, the Inachide, 
Maiide, and Periceride. 
Family 1.—Inachide. 
The eyes*are non-retractile, or retractile against the 
sides of the carapace. In general the orbits are not de- 
