COMPLEMENTAL MALE. 271 



parallel to the surface of attachment. The largest speci- 

 men measured transversely, through the scuta and terga, 

 was Troths of an inch in breadth ; another was only ^ths 

 to sloths : this latter specimen, measured longitudinally, 

 from the base of the carina to the tips of the terga, was 

 Tgjfeths of an inch. A scutum of the largest specimen 

 was J^ths in length. The scuta and terga are broadly 

 oval, with the primordial valves very plain at their upper 

 ends. I may here mention, that in a central line between 

 the scuta, I observed the apparently single, minute, black 

 eye, as in ordinary Cirripedia. 



The Carina is straight, triangular, and internally slightly 

 concave ; its basal margin descends far below the basal 

 points of the terga. 



The Hostrum is shorter, and internally more concave 

 than the carina : I believe it projects more abruptly out- 

 wards than is represented in the figure. 



The Peduncle commences some little way below the scuta: 

 it is narrow and very short : it is finely villose : it is 

 lined by delicate transverse striaeless muscles, within which 

 there are the usual stronger, longitudinal muscles. The 

 base is flat and truncated. I examined, and carefully 

 compared, the prehensile antennae with those of the 

 hermaphrodite, and found every part and every measure- 

 ment the same. The full importance of this identity will 

 hereafter be more fully insisted on. The antennae are 

 represented of their proper proportional size in fig. 3. 



Mouth. — The labrum, as in the hermaphrodite, is highly 

 bullate, and far removed from the adductor scutorum 

 muscle. The Palpi are small and triangular, with their 

 blunt apices clothed with a very few scattered bristles. 



Mandibles, with only three teeth, and the lower angle 

 minute, slightly pectinated; the first tooth is distant 

 from the second, and larger than it. Width of the whole 

 organ, *0021 of an inch. 



Maxillce, bearing only a few spines, furnished with a long 

 apodeme; beneath the upper large pair there is a notch, 

 under which there are two spines of considerable size and 



