98 Mr H. Goodsir on the Sexes of the Cirripeds^ S^c. 



The appearance put on by the ova, shortly before the young 

 animal has burst from the ovisac, is that represented in PL 

 IV., fig. 13 ; it is semitransparent, and the motions of the animal 

 may be observed through the membranes. 



The larva, shortly after its escape from the ovum, is repre- 

 sented in PL, IV., fig. 15. The body is of a pyriform shape, 

 being large and rounded anteriorly, while it is small and pointed 

 posteriorly. It is almost colourless in some parts of its body, 

 but the general shade is dark brown, which is deepest in the 

 centre. 



The eye is large, of a black colour, is situated in the mesial 

 line, near the anterior edge ; it is of a quadrate shape. Al- 

 most in a line with the eye, and from the lateral edge of each 

 side of the body, there arises a short horn-like process which 

 curves slightly forwards. 



The body is composed of a number of segments, which are 

 most numerous at its posterior extremity ; the last segment is 

 armed with three sharp strong spines which project back- 

 wards. 



This animal has three pairs of extremities, the first of which 

 is single, and the other two are double. The first extremity 

 is composed of a greater or less number of long spines. The 

 two following pairs of extremities are each double, or composed 

 of two parts, which arise from a common peduncle. The an- 

 terior part is articulated, but the posterior consists of one 

 piece only, which is almost as large as the anterior or articu- 

 lated portion. Each of these divisions is armed with a great 

 number of long spines. The third or last extremity is formed 

 in the same way as that last described, but is not so large. 



After the Balani have been about a week in existence, they 

 put on the appearance represented in PL III., fig. 8. They 

 have changed in their appearance to a very considerable ex- 

 tent, are rather larger and much more active in their habits, 

 than those which had escaped from the ovum more recently. 



A large segment has originated at the anterior part of the 

 body, and the horn-like processes described formerly, now form 

 the posterior and external angles of this segment ; it also sup- 

 ports the first pair of feet, which are constantly directed for- 

 wards, and are now apparently composed of three segments 

 only. 



