234 SCALPELLUM VULGARE, 



displayed. The abdominal lobe is smooth, and cannot 

 be stretched, or turned inside out by pulling the above 

 muscles. On the thorax, corresponding with the inter- 

 spaces between the five transverse articulations, there are 

 four pair of short limbs, but their bases, I believe, are 

 prolonged across the inner or ventral surface of the thorax, 

 so as almost to touch each other. These limbs, I believe, 

 have no articulations, except, perhaps, where united to the 

 thorax. The anterior or lowest limb, on each side, sup- 

 ports two or sometimes only a single spine ; this pair 

 is rather smaller than the second, and is placed a little 

 more distant from it, than are the upper pairs from each 

 other. The second pair differs from the upper two, only 

 in having its three spines a very little shorter. The two 

 upper or posterior pair exactly resemble each other ; each 

 has two spines on the summit, and a third seated lower 

 down, on a little notch on the outer side, but with its 

 point on a level with the others. The points of the spines 

 of the two upper limbs, stand on a level with the ex- 

 ternal spines at the end of the abdomen. All the spines 

 are of excessive tenuity and sharpness ; they are straight, 

 long, and not plumose. 



The abdominal lobe is square, and from not being 

 wrinkled, has a different appearance from the thorax : 

 on each of the posterior angles, there are three mode- 

 rately long, very sharp spines, with the tips of the outer 

 pair bent a little inwards ; in the middle between them, 

 there are two little spines, and a little below and outside 

 these latter, on the ventral surface, there are two other 

 longer spines with their tips bent inwards ; and again, 

 lower down, two other pair, one beneath the other, of 

 short spines. Perhaps, the three pair of spines on the 

 ventral surface, mark the three segments, which are 

 distinct on the abdomen of the larva in the last stage 

 of its development, in Lepas and other genera. In the 

 same way, it is probable that the lateral spine on the 

 notch in each limb, marks the point where, in the larva, 

 there is an articulation. Altogether, there are seven 



