194 IBLA CUMINGII, 



tain extent, those of the female, differing from them in 

 being less prominent, — in the outline being more rounded, 

 with the notches even less distinct, — and in the spines 

 being fewer. The apodeme is short and broad. 



The Outer Maxilla (tig. 6) are pointed, with a small 

 tuft of bristles at the apex ; they are much less hairy 

 than in the female, but have nearly the same unusual 

 shape. Outside their bases, and between them and 

 the inner maxillae, the two well-developed, tubular, flat- 

 tened, square- topped, olfactory orifices, project in exactly 

 the same remarkable position as in the female ; these are 

 not represented in fig. 2, though sometimes they can be 

 very distinctly seen, when the mouth is viewed from 

 vertically above. 



Thorax and Cirri. — The thorax is in a rudimentary 

 condition: I did not observe the usual articulations. The 

 whole, as seen from vertically above, is of small size, 

 compared with the mouth ; the outline is accurately shown 

 by dotted lines in Tab. 5, fig. 2, together with the posi- 

 tions of the two pair of cirri, the caudal appendages, and 

 anus. The posterior end of the thorax does not rise to 

 the level of the summit of the mouth; and the thorax 

 seems of no service, excepting perhaps as a sort of outer 

 lip to protect the mouth. The cirri are in an extreme 

 state of abortion, and evidently functionless; they are 

 lined with purplish corium, without the vestige of a 

 muscle ; they are usually distorted and bent in different 

 directions ; they vary in size, and even those on opposite 

 sides of the same individual, sometimes do not corres- 

 pond, and do not arise from exactly corresponding points 

 of the thorax. There are always two pair of cirri, which, 

 as I conclude from the position of the excretory orifices, 

 answer to the fifth and sixth pair in other Cirripedes. 

 Each cirrus (fig. 4) usually carries only one ramus, placed 

 on a large basal segment, evidently corresponding to the 

 pedicel of a normal cirrus. The posterior are larger 

 than the anterior cirri, which latter spring from points a 

 little lower down on the thorax. In the posterior cirrus 



