84 
MODERN SYSTEM. 
b. Interior antenna with moderate footstalks . 
Fam. IV. Astacidje.. Leach’s MSS. 
Antenna inserted in the same horizontal line, interior ones with two 
setae, the exterior ones simple : legs for walking ten, anterior pail o 
these largest. 
Stirps 1 . — Exterior lamella ol ihe tail composed of one part. 
Genus 28. GEBIA. Leacli. 
Two anterior legs equal, subdidact vie, with the thumb short : interior an - 
tenna with an elongate peduncle; the second joint shortest, the third 
largest and cylindric : external double palpi with the third joint of the 
internal footstalk shortest: tail with broad lamellae; the exterior 
ones costated, the middle one quadrate. 
Sp. 1. Geb. Deltiiura. Abdomen with the back membranaceous : tad with 
the apex of the exterior lamella dilated and somewhat rounded; in- 
terior one truncate, and formed like the Greek delta. 
Gebia dcltaura. Leach, Trans. Linn. Soc. xi. 343.— Mai. PodopteBnt- 
lab. 31. fig. 9, 10. 
Inhabits beneath the sand on the southern coast of Devonshire, and is 
found by digging to the depth of two or three feet. 
Genus 24. CALLIANASSA. Leach. 
Four anterior kgs didactyle ; anterior pair largest, very unequal ; second 
pair less; third pair monodactyle; fourth and ldllt pairs spurious* 
internal antennae with an elongate Inarticulate peduncle, the secou 1 ^ 
joint longest: external double, palpi with the second joint ot the mte>^ 
nal footstalk largest and compressed: tail with broad lamellae; tn 
middle process elongate-triangular, with the apex rounded. 
The thorax anteriorly abruptly subacuminatc; the rostriform pro- 
cess divided from the 'shell by a suture: anterior pair of legs very 
much compressed, the hand articulated : the larger leg with tire base 
of its wrist furnished with a curved process. 
Sp. 1. Cal. subterranca. Shell with the rostriform process with one lon- 
gitudinal ridge, the point rounded. ^ ... 
Cancer Astacus subterraneus. Montagu, Trans. Linn. Soc. xi. CallianasS 
subterranca. Leach, Kdin. Ena/cl. vii. 400. — Truns. Linn. Soc. xi. 31 ->- 
Supp.to Encycl. Brit.i. 420. — Maine. Podoph. Brit. tab. 32. 
This animal lives beneath the sand on the sea-shore. It was £> '_ 
described by Montagu, who found it by digging in a sand-bank 1 
the estuary of Kingsbridge, on the southern coast of Devon. 
Genus 25. AXIUS. T-cach. 
Four anterior kgs didactyle; anterior pair largest, and somewhat 
equal; third, fourth, and fifth pairs furnished with a compress 
claw: interior emtemue With a three-jointed peduncle, the first jo^ 
longest : external double palpi with the two first joints somewhat Wb 
