CLASS T. CRUSTACEA, 
10S 
Genus 5. LEUCOTHOE. Leach. 
Anterior pair of kgs didactyle; the thumb biarticulate : second pair with 
a dilated and compressed hand, furnished with a crooked thumb. 
Sp. 1 . Leu. articulosa. 
Cancer articulosus. Montagu, Trans. Lhm.Soc. vii. 71. t. 6.f. 6 . Leu- 
cothde articulosa. Leacli, Edin. Encyd. vii. 403. Trans. Linn. Soi. 
xi. 358. — Supp. to Encyd. Brit. i. 423. 
Inhabits the British sea, but is very rare. 
Stirps 3 . — el«toira<£ four-jointed, the last segment composed of several 
little joints; upper ones longest. 
Subdivision 1 . — Four anterior legs monodactyle, second pair with a much 
dilated compressed hand. 
Genus 6. METJTA. Leach. 
Anterior pair of legs monodactyle; second pair with the thumb indexed 
on the palm: tail on each side with an elongate foliaccous lamella. 
Sp.l. Mel. palmate. Body blackish : antennas and legs annotated with 
pale colour. .. ,, , 
Cancer palmatus. Montagu, Trans. Linn. Soc. vu. 69. . Mclita palma- 
ta. Leach, Edm. Encyd. vii. 103.— Trans. Linn. Soc. xi. 358.— Supp. to 
Fncycl. Brit. i. 425. pi. 21. 
Inhabits the sea shore on the Devonshire coast under stones. 
Genus 7. MiERA. Leach. . , 
Four anterior legs didactyle ; thumb of the second pair bent on the side 
of the hand : tail with no foliaceous appendices. 
S P- 1 . Mcc. grossimana. . . 
Cancer Gammarus grossimanus. Montagu, Trans. Lmn. Soc.ik. . T. t. 1. 
f 5 . Mara grossimana. Leach, Edm. Encycl. vii. 403. Trans. Lmn, 
Sue, xi. 359. — Supp. to Encyd. Brit. i. 425. 
Inhabits the southern coast of Devonshire beneath stones. 
Subdivision 2 .— Two anterior pair of legs monodactyle and alike. 
Genus 8 . GAMMARUS. Lair., Leach. 
Superior antenna furnished at the base ot the fourth joint with a little 
jointed seta: tail above with bundles of spines. 
* Tail with the superior double styles, having the upper style process 
very short. , 
S P- 1. Gam. aqmlicus. Process between the antenna: rounded, obtuse. 
Gammarus Pules. Leach, Edin. Encyd. vii. 402—432. Gammarus aqua- 
tions. Leach, Trans. Linn. Soc. xi. 359. — Supp. to Encyd. Brit. l. 125. 
Inhabits ponds, ditches, and springs in great plenty. 
S P- 2. Gam. marinus. Process between the antenna subacummate. 
Gammarus marinus. Leach, Trans. Linn. Soc. xi. 359— Supp. to Encyd, 
Brit. i. 425 
Inhabits the sea on the southern coast of Devonshire in plenty. 
