CLASS r. CRUSTACEA, 99 



scribed it in the eleventh volume of the Transactions of the Linnean 

 Sucidj/, p. 3 lii. 



"Falamon sci'rat us of ¥'dhric\us is distinct, and, if his description be 

 correct, it is not even refurublc to this genus ; behaving expressly 

 given as its specific chavdcicr ' Antinnis posticis bfidis,^ (hinder an- 

 tenna' bitid ;) -whereas, in his generic character, he has stated these 

 organs to be trifid (' Antenna: superiores trijida.' ") 



Genus 36. ATHANAS. Leacfi. 

 Four anterior legs didactylc : anterior pair larger than the second pair: 

 external double palpi witli the last joint longer than the preceding 

 joint. 

 Sp. 1. Ath. nilescens. Rostrxnn straight, and simple. 

 Cancer (^Astacus) nitescens. JMontagu's MSS. Athanas nitescens. Leach, 

 Trans. Linn. Soc. — Supp. to Enc^cl. Brit. — il/«/. Fodoph. Brit. tub. 44. 

 Inhabits the southern coast of Devonshire. 



Stirps 5. — E.rtcrnal antenna; inserted below the internal : interior ones 

 with a large scale at their base. Legs for movement sixteen. 



Genus 37. MYSIS. Latr., Leach. Praunus. Leach. 



Legs bifid, the last joint of the four anterior pairs with the interior 

 lacinia uniarticidate, ovate, compressed ; of the other pairs of legs 

 niulliarticulate : external double /^///u with the middle joint of 'the 

 internal footstalk longest, the fust very short. 



At the base of the abdomen of the female is situated the external 

 uterus, composed of tvvo valve-like membranes, in which the young 

 ones, just excluded from the egg, live and grow until they become 

 strong enough to take care of themselves. 



The animals of this genus swim with tlieir head uppermost, and with 

 their eyes spreading, which gives them a singular and grotesque ap- 

 pearance. 



* hitermediate lamella of the tail emarginate. 



Sp. 1. 3It/sis spinulosa. Tail with the intermediate lamella externally 

 spinulose ; the apex acutely emarginate ; exterior lamellcE acuminate, 

 and very broadly ciliated. 



Praimus flexuosus. Ixach, Edin. Enctjcl. vii. 401. ISIysis spinulosa. 

 Leach, Trans. Linn. Soc. xi. 350. — Supp. to Encycl. Brit. i. 422. 



Inhabits the Frith of Forth near Leith. 



" Colour when alive, pellucid cinereous : eyes black, red at their 

 base : lamina of the external antenna; with a black longitudinal line 

 and spots. A clouded spot on each side of the hinder part of the 

 thorax, and another above the legs. Every segment of the body 

 most beautifully marked with a reddish-rust coloured spot, disposed 

 in an arborescent form ; tail fin spotted with the same colour, mixed 

 with black : pouch of the female with two rows of fuscous-black 

 spots : under side of the abdomen regularly mottled with rufous black." 



c 2 



