14 LEPADID.E. 



these organs, and attached by their tips, through some 

 unknown means, to the sack of the parent, apparently in 

 the same maimer as Burmeister's larva was attached to 

 the sea-weed. I will only further remark on the larva 

 of this Second stage, that its chief development since the 

 first stage, has been towards its anterior end. The next 

 great development, to be immediately described, is towards 

 the posterior end of the animal. 



Larva, Last Stage. — My chief examination has been 

 directed, at this stage of development, to the larvae of 

 Lepas australis, which are of unusual size, namely, from 

 •065 to even almost '1 of an inch in length; I examined, 

 however, the larvse of several other species of Lepas, of 

 Ibla and of Balanus, with less care, bat sufficiently to 

 show that in all essential points of organisation they were 

 identical ; this, indeed, might have been inferred from 

 the similarity of the larval prehensile antennas, preserved 

 in the bases of all mature Cirripedes, and which I have 

 carefully inspected in almost every genus. The larvse in 

 this final stage, in most of the genera, have increased many 

 times in size since their exclusion from the egg; for 

 instance, in Lepas australis, from *007 to '065, or even to 

 *1 of an inch. They are now much compressed, nearly 

 of the shape of a cypris or mussel-shell, with the anterior 

 end the thickest, the sternal surface nearly or quite 

 straight, and the dorsal arched. Almost the whole of 

 what is externally visible consists of the carapace ; for 

 the thorax and limbs are hidden and enclosed by its 

 backward prolongation ; and even at the anterior end of 

 the animal, the narrow sternal surface can be drawn up, 

 so as to be likewise enclosed. As in several Stomapod 

 crustaceans, the part of the head bearing the antennse 

 and organs of sense, in front of the mouth, equals, or 

 even exceeds in length, and more than exceeds in bulk, 

 the posterior part of the body, consisting of the enclosed 

 thorax and abdomen. I will now briefly describe, in the 

 following order, the carapace, the organs of sense, mouth, 

 thorax and limbs, abdomen, and internal viscera. 



