METAMORPHOSES. 17 



Burmeister considers as the basal segments of the an- 

 tennae : as they are not cylindrical, I do not see the 

 grounds for this conclusion : their posterior ends are 

 rounded, and the membrane forming them is reflected 

 inwards, in the form of two, forked, horny apodemes, 

 together resembling two letters, UU, close together; these 

 project up, inside the animal, for at least one third of its 

 thickness from the sternal to the dorsal surface. The 

 two great, almost spherical eyes in L. australis, each -^tli 

 of an inch in diameter, are attached to the outer arms, 

 thus, •UU # , in the position of the two full stops. Hence 

 the eyes are included within the carapace. Each eye con- 

 sists of eight or ten lenses, varying in diameter in the 

 same individual from ^ to ^th of an inch, enclosed in 

 a common membranous bag or cornea, and thus attached 

 to the outer apodemes. The lenses are surrounded half 

 way up by a layer of dark pigment-cells. The nerve does 

 not enter the bluntly-pointed basal end of the common 

 eye, but on one side of the apodeme. The structure here 

 described is exactly that found, according to Milne 

 Edwards, in certain Crustacea. In specimens just 

 attac7ied, in which no absorption has taken place, 

 two long muscles with transverse striae may be found 

 attached to the knobbed tips of the two middle arms 

 of the two °UU°, and running up to the antero-dorsal 

 surface of the carapace, where they are attached ; other 

 muscles (without transverse striae) are attached round 

 the bases, on both sides of both forks. The action of 

 these muscles would inevitably move the eyes, but I 

 suspect that their function may be to draw up the narrow, 

 deeply folded, sternal surface, and thus cause the retrac- 

 tion of the great prehensile antennae within the carapace. 

 Mouth, — This is seated in exactly the same position 

 as in the mature Cirripede, on a slight prominence, 

 fronting the thoracic limbs, and so far within the cara- 

 pace, that it was obviously quite unfitted for the seizure 

 of prey; and it was equally obvious, that the limbs were 

 natatory, and incapable of carrying food to the mouth. 



2 



