10 LEPADID^E. 



teriorly to them, on the sternal surface, near each other, 

 there are two other minute, doubly curved, pointed 

 horns, about *004 in length, directed posteriorly; and 

 within these I again saw a most delicate articulated fili- 

 formecl organ on a thicker pedicel : in an excellent draw- 

 ing, by Mr. C. S. Bate, of the larva of a Chthamalus 

 {Balanus punctatus of British authors), after having 

 kept alive and moulted once, these organs are dis- 

 tinctly shown as articulated antennae (without a case), 

 directed forwards : hence, before the first moult in Scal- 

 pellum, we have two pair of antennae in process of for- 

 mation. Anteriorly to the bases of these smaller antennae 

 is seated the heart-shaped eye, (as I believe it to be,) 

 •001 in diameter, with apparently a single lens, sur- 

 rounded, except at the apex, by dark-reddish pigment- 

 cells. In some cases, as in some species of Lepas, the 

 larvae, when first excluded from the egg, have not an eye, 

 or a very imperfect one. 



There are three pairs of limbs, seated close together 

 in a longitudinal line, but some way apart in a trans- 

 verse direction : the first pair always consists of a single 

 spinose ramus, it is not articulated in Scalpellum, but is 

 inuiti- articulate in some genera ; it is directed forwards. 

 The other two pair have each two rami, supported on 

 a common haunch or pedicel : in both pair, the longer 

 ramus is multi- articulate, and the shorter ramus is without 

 articulations, or with only traces of them : the longer 

 spines borne on these limbs (at least, in Scalpellum and 

 Chthamalus,) are finely plumose. The abdomen terminates, 

 a little beyond the posterior end of the carapace, in a 

 slightly upturned horny point ; a short distance anteriorly 

 to this point, a strong, spinose, forked projection depends 

 from the abdominal surface. 



Messrs. V. Thompson, Goodsir, and Bate, have kept 

 alive for several days the larvae of Lepas, Conchoderma, 

 Balanus, Verruca, and Chthamalus, and have described 

 the changes which supervene between the first and third 

 exuviations. The most conspicuous new character is the 



