30 CIRRIPEDIA. 



by her, and capable of seizing, by the movements of 

 its pedunculated body, any minute animals or substances 

 found within her sack ; (2d), a female with successive pairs 

 of short-lived, mouthless males, inhabiting pouches on each 

 side under her scutal valves ; (3d), a female with many, in 

 one instance fourteen, short-lived males, destitute of mouth, 

 thorax, and appendages, but furnished with a stupendously 

 long male organ, attached to a thickened portion of her 

 outer integuments, but lying within the cavity which she 

 has excavated ; (4th), an hermaphrodite with a male attached 

 within the sack, capable of feeding itself, as in the first 

 case ; (5th), an hermaphrodite with from one to three 

 males, organised like ordinary Cirripedes, and apparently 

 capable of seizing prey in the common way ; and attached 

 between the scuta, and thus protected ; (6th and lastly), 

 an hermaphrodite with from one or two up to five or six, 

 short-lived, mouthless males, like those in the second case, 

 attached in one particular spot, on each side of the orifice 

 leading into the sack. 



I.— Order THORACICA. 



Cirripedia having a carapace, consisting either of a capi- 

 tulum on a peduncle, or of an operculated shell ivith a basis. 

 Body formed of six thoracic segments, generally furnished 

 with six pairs of cirri ; abdomen rudimentary, but often 

 bearing caudal appendages ; mouth with the labrum not 

 capable of independent movements ; larva firstly uniocidar, 

 with three pairs of legs, lastly, binocular, with six pairs of 

 thoracic legs. 



In the sketch of the three Orders given in the Introduc- 

 tion, it will have been seen that the differences in their 

 structure are so great, that it would have been hardly possi- 

 ble to have given a single blended account of the whole 

 Class. But as all common Cirripedes are included in the 

 present Order, here would have been the natural place for 

 a full description of their external and internal structure. 

 Having, however, been necessarily, yet perhaps unfor- 



