242, A HISTORY OF RECENT CRUSTACEA 
place of the little crab (carcinion) in companionship with 
the Pinna. In Australian and other Hastern waters, Pon- 
tonia meleagrine (Peters) occupies the shell of the pearl 
oyster, Meleagrina margaritifera, and probably also that of 
Tridacna squamosa. Professor 'Th. Barrois found the male 
and female of Pontonia custos constantly together in large 
specimens of Pinna rudis at the Azores. 
Typton, Costa, 1844, though much like Pontonia in 
many points, has the dorsal surface arched and the rostrum 
laterally compressed, an ocellus on the hind margin of the 
eye, both flagella of the first antennz undivided, the scale 
of the second rudimentary, and six or seven pairs of 
branchie.  ‘T'ypton spongucola, Costa, is, as its name im- 
plies, a lodger in sponges; it is a British as well as a 
Mediterranean species. 
Family 4.—Caricyphide. 
The rostrum is slender and sharp-pointed. The first 
antenne have two short flagella, the second a long and 
narrow scale. ‘The first two pairs of trunk-legs are chelate, 
subequal. Frequently the third segment of the pleon is 
dorsally elevated and compressed. ‘The telson is long and 
slender. Here are placed three genera—Caricyphus, ‘the 
bowed shrimp ;’ Rhomaleocaris, ‘ the robust shrimp ;’ Aného- . 
caris, ‘the immature shrimp,’ all instituted by Spence Bate 
in 1888, and all from immature specimens, the largest of 
which was three-fifths of an inch in length. The seven 
species included in these three genera are all from Eastern 
and Southern waters. Though they will interest the 
specialist concerned with development, they seem but ill- 
suited to constitute a separate family. 
Family 5.—Acanthephyride. 
The animal is laterally compressed and dorsally cari- 
nate. The first antennae have two long flagella; the 
second a sharp and rigid scale. ‘The mandibles have molar 
tubercle, cutting edge, and ‘ palp.’ The first two pairs of 
trunk-legs are slender, subequal. The telson is long, 
