Mr H. Goodsir on the Sexes of the Cirrtpeds, 8f€. 97 



are almost equal in length to the third, which has its extremity 

 armed with two spines. 



Five pairs of very short, but thick and powerful, legs arise 

 from the following segments or segment: — 



Each of them is three pointed ; the first joint is thick and 

 short, the second much more slender, and the third or last is 

 spherical, armed at its extremity with a small claw. 



From each side of the six following segments of the body, 

 there arises a long flattish scale, each of which scales has its ex- 

 tremity armed with two, three, or four long filamentous, slender, 

 spines, which are quite stiff and directed backwards. The two 

 last, or terminal of these scales, arc the strongest, and also the 

 longest, the spines gradually decreasing in length as they ap- 

 proach nearer to the anterior extremity. 



When this animal is taken from its natural habitat, its mo- 

 tions are very feeble, and it is apparently quite helpless. The 

 organs of sight seem to be awanting, or are very minute, the 

 habits of the animal being such as not to require them. The 

 ova are large, and gradually lengthen out into the form of 

 a double cone, as the animal is ready to burst through the 

 ovisac. 



SECTION II. ON THE LARVA OF BALANUS BALANOIDES. 



During the greater part of the months of April and May 

 of this year (1843), the water around the Island of May has 

 been darkened with innumerable shoals of the young of the 

 common Balanus. These Cirripeds adhere, in vast numbers, 

 to the sides of the precipitous rocks beneath low water-mark. 



A number of these were taken from the rocks, and those 

 which were found to bo loaded with spawn were put into a se- 

 parate vessel by themselves, and the water regularly changed 

 upon them until the young animal escaped. In this way their 

 development and structure was made out satisfactorily. 



In those where the ova had but recently escaped from the 

 ovaries, these were closely packed together in the bottom of 

 the cavity of the mantle, in large and firm layers ; but as they 

 became more matured, these masses became more broken up 

 and disconnected, and gradually disappeared as the young 

 wore expelled from the body of the mother. 



VOL. XXXV. NO. LXIX. JULY 1843. Q 



