640 ARTICULATA. 



Order contains seventeen genera ; of which we Iiave given representations 

 of the following : 



Leodice Sanguinea. — The Bloody Leodice. Plate Ixxxii. fig. 1. With 

 pectinated brancliiae ; most lengthened towards the centre of the body ; tail 

 with a double cetaceous termination- Inhabits the Indian ocean. 



Spio quadricornis. — The Four Horned Spio. — Plate Ixxxii. fig. 7. With 

 four tentacula, the external ones filiform, and the intermediate thick and 

 short. Inhabits the British coasts. 



Halithea aculeata. — The Spiued Halithea. Plate Ixxxii. fig. 2. Oblong, 

 with shining spines and hairs; dorsal scales dotted with brown. Inhabits 

 the British coasts. 



ORDER III. — AFODES. 



Without feet ; branchiae, when they exist, disposed interiorly along the 

 body. It consists of ten Genera. 



Pontobdella spinulosa. — The Spined Pontobdella. Plate Ixxxii. fig. 3 

 Body with remote spines, and aunulated. Inhabits the British seas, adher. 

 ii)g to the skate. 



CLASS VI.— CRUSTACEA. 



Animals without vertebral column, having generally a crustaceous cover, 

 ing, more or less solid ; the members of the body articulated, provided 

 with distinct organs of circulation, and respiring by means of branchiae. — 

 For the Physiology of Crustaceous animals, see vol. iv. page 2. Tt's class 

 consists of nine orders. 



ORDER I.— DECAPODA. 



With the branchiae of a pyramidal shape in the form of leaflets, situated 

 near the last four feet-jaws, and of the feet, concealed under the sides of 

 the shell ; head not distinct from the trunk of the body. This order con- 

 tains seventy-six genera, of which we have given representations of the fol. 

 lowing. 



Pinnotheres pisum.—'V\\& Fishing Pinnotheres or Pea Crab. Plate Ixxxii. 

 fig. 4. Described, vol. iv. page 11. 



Gonoplax bispinosa. — The Two-Spined Gonoplax. Plate Ixxxii. fig. 5. 

 Shell armed with two spines on each side ; wrists, and arms above with one 

 internal spine. Inhabits the coast of England. 



Pilumnus hirtellus. — The Hairy Pilumnus. Plate Ixxxii. fig. 6. Shell 

 with five teeth on each side ; body and legs thickly furnished with bristles ; 

 claws muricated on the outside. Inhabits the Devonshire coast. 



Cancer pagurits. — The Pagurus or Common Crab. Plate Ixxxii. fig. 8. 

 Described, vol. iv. page 12. 



Pirimela denticulata- — The Toothed Pirimela. Plate Ixxxii. fig. 9. Shell 

 tubercular, each of the anterior sides provided with five teeth ; three teeth 

 in front, the centre ones largest. Inhabits the British coasts. 



Portunus corrugatus- — The Wrinkled Portunus. Plate Ixxxii. fig. 10. 

 Wrinkled and granulated transversely, with five teeth before on each side ; 

 first and second joints of the claws with a epine ou each ; forceps serrated j 



