556 PHILOSOPHY OF ZOOLOGY. 



The first, constituting the Epizoariee of IjA^i ark *, con- 

 tains the genera Chondracanthus, Lernaea, and Entomoda. 

 The species reside in the gills, and different parts of the 

 surface of fishes. Some species seem to attach themselves 

 to the eyes, as appears to be the case in the one which ad- 

 heres to the Greenland shark -j-. 



The second, termed by Dr Leach Podosomata, includes 

 the genera Pycnogonum, Phoxichilus, Nymphum, and 

 Amothea. 



Order II. — Pulmonary aerating organs. 



Section 1. — Arach^ida. 

 Head destitute of antennae. Eyes simple. 



1st Tribe. 



Lungs in the form of lateral sacs. 



The legs are always twelve in number, two pair of which 

 serve as auxiliary maxillae, and the remaining four pair 

 execute locomotion. The eyes vary from six to eight, and 

 have a dorsal aspect. 



A. Palpi bearing the male organs in the last joint. The 

 palpi themselves are of a moderate size, and do not termi- 

 nate in a large moveable claw; neither are they chelife- 

 rous. The second pair of auxiliary maxillae are pierced at 

 the extremity of the termination of a poison duct. The 

 abdomen is pedunculated, and without rings, and the pulmo- 

 nary sacs, which are two in number, are seated near its base. 

 The first stomach has numerous cceca, and the second is sur- 

 rounded by the liver. The pores which give issue to the 

 matter with which the threads for the construction of the 

 web are formed, are seated at the anus. These threads 

 they can eject to a considerable distance, and afterwards em- 



• Hist. Nat. des An. sans "Vert. vol. iii. p. 225. 



■{■ Scoresby's Arctic Regions, vol. i. p. 53S. lab. xv. fig. 5. 



