*IS3SJ| t -"■■ mrcinged in Natural FamiUes* ; 1 9D 



consisting of a longitudinal series of ganglia united by a double 



cord, and several scattered ganglia, 



^: Mouth placed at the base (or attached part) of the animal, 



furnished with three pair of horny jaws. Alimentary canal 



mostly simple, vent situated at the base of the proboscis-like 



terminal tube. The gills pectinate, one on fcach side at the base 



of the anterior pair of feet» 



' Hermaphrodite, oviparous, the aperture of the organs of reprof 



duction placed at the end of the proboscis-like tube. 



Attached directly, or througb the medium of a tendinous tube, 

 to marine bodies. Living on small sea animals which they col- 

 lect by means of their legs. Growing very rapidly. 



Linna&us considered the whole of the Cirripedes as one genus. 

 The French naturahsts generally look upon them as an order of 

 mollusca, but Mr. W. Mac Leay has lately proposed, I believe 

 very properly, that they should be regarded as an annectant 

 class similar in rank to the Annelides, Tunicata, &c. Classes 

 are usually divided into orders, but on account of the small num- 

 ber of genera at present known in this class, I have thought it 

 right to follow the plan used by Mr. W. Mac Leay in his excel- 

 lent paper on the Tunicata, just published in the Linnean Tran* 

 sactions, and to divide it into Families. 



Lister divided this group of animals into two genera, calling 

 them Anatifera and Balanus. Bruguieres followed him, but 

 changed the former name for that of Lepas, His genera may 

 be considered as the primary division of the class, and the for?- 

 toet appears to be the Normal group. 



Synopsis of the Families. 

 L Body compressed^ peduncled. Anatifera, List, 



Peduncle naked ANATiFERiDiE. 



Peduncle scaly or hairy PoLLiciPEDiDiE. 



IL Body coronal, sessile, Balanus, List, 

 Operculum valves articulated. 



Base concave Pyrgom ATip^. 



Base flat or none Balanidje. 



Operculum valves separate Coronuljp^. 



§ 1. Normal Group? — Body oval, compressed; open on the 

 posterior ventral part, and prolonged to be fixed into a fleshy pe- 

 duncle ; shelly valves, five or more, imbedded in the coriaceous 

 tunic, not articulated together, increasing by addition to their 

 whole edge. 



Fam. 1. Anatiferid.e, Gray, 



Body compressed; shelly valves, five or eight; one pair 

 behind, and one or two. pair before the legs; one plate on the 

 back (rarely divided across) ; sheath of the peduncle smooth j- 

 destitute of additional scales^ . . ... ,.m... . 



