CLASS I. CRUSTACEA. 91 



joints: palpi very hairy, the middle joint shortest, the third a little 

 longer than the tirst: fou}- anterior claws witli their tips bent: four 

 hinder ones abruptly cur\ed at their base. 



Sp. 1. Mac. Phalaugium. Beak acuminate, much shorter than the an- 

 tennae : shell bebind the rostrum, with three tubercles placed in a tri- 

 angle, the hinder tubercle largest : arms internally subscabrous and 

 hirsute. 



Cancer Phalangium. Penn. Brit. Zool.'iv.S. pl.9. Jig. 17. Macropus 

 longirostris. Lafr. Gen. Crust, et Insect. Macropodia longiroslris. 

 Leach, Ediu. Encyct.xn. — Zool. Mi^c. ii. 18. — Trans. Linn. Soc. xi. 331. 

 —Mai. Fodoph. Brit. tab. 23. 



Inhabits \he mouths of rivers, and is verj- common in Great Britain. 



D. Abdomen of both sexes four-jointed. Two anterior legs didaciylc. 



Fam.IX. Leucosiadx. 



Genus 18. EBALTA. Leach. 



Shell rhomboidal, produced in front; the sides entire: anterior pair of 

 /egs depressed, nmcli larger than the rest; arms subangulated; fin- 

 gers subdeflexed : external pedipulpes with their external footstalk li- 

 near : abdomen of the male with its last joint at its base furnished 

 witli a dentiform process. 



Sp. 1. Eb. Pennantii. Shell granulated, witli an irregidar elevated cross : 

 abdomen widi 3 — 6 joints confluent. 



Cancer tuberosus. Penn. Orn. Zool. iv. 8. ^ 9. A. f. 19. Ebalia Pennan- 

 tii. Leach, Malac. Podoph. Brit. t. '25. f. 1 — 6. (5* & Q . 



Order TI. MACROURA. 



This Order contains the Families Pagurii, Palinurini, Astacini, and 

 Squillai-es of Latreille. 



Division I.— Tail on each side with simple appendices. 



Fam. I. Pagurid.e. Leach. 

 Legs ten; anterior pair largest and dactyle. 



Genus 19. PAGURUS. Fair., Latr., Bosc, Leach. 

 External antenna with the second joint of their peduncle with a move- 

 able spine affixed to the apex above : abdomen membranaceous : tail 

 three-jdinted, cnistaceous; the second joint on each side appendicu- 

 lated : four hinder legs spurious, short, didactyle. 



The curious economy of the genus Pagurus attracted the attention 

 of the ancients. One species is well described by Aristotle. 



All the species are parasitical, and inhabit the cavities of turlii- 

 nated univalves. They all change their habitation during their 

 growth, first occupying the smallest shells, and latterly those of very 



