28 Mr. J. Lubbock on a new genus of Calanidse. 



two-jointed branch, both clothed internally and at the apex with 

 long setose hairs, and the outer branch also bearing several 

 short, stout spines externally, and showing traces of other joints. 



Fifth pair of thoracic leys. Female. Small, simple, consisting 

 of a basal joint, bearing two, a large and a smaller, simple slightly 

 curved pointed joints ; the outer and larger one bearing one or 

 two small, short spines (fig. 10). 



Male (fig. 9). The right leg in the male is large and pre- 

 hensile ; the first joint somewhat pentagonal, broad ; the second 

 simple, cylindrical; the third very much swollen at the apex, 

 containing a very powerful muscle, bearing at its external basal 

 angle a large spine, which, with the claw articulated at the cor- 

 responding apical angle, forms a very powerful prehensile appa- 

 ratus. The left simpler, smaller leg (fig. 9 a) is three-jointed and 

 gradually tapers to the apex, where there are two, a longer and 

 a shorter, strong, slightly bent spines. Internally at its apex it 

 bears a tuft of very fine short hairs. Attached to the basal joint 

 is a two-jointed appendage, not so long as the leg itself, and 

 whose second joint is very curiously ringed (the rings however, 

 at least at the base, do not go quite across), and evidently exten- 

 sible, as in some specimens it was much longer and thinner than in 

 others. In it (fig. 9 b) was a wide vessel containing a brown pulpy 

 substance, but I could not trace it quite to the apex (though as 

 far as the second ring), nor see any opening, which, considering 

 the minuteness of the object, is not perhaps to be wondered at. 

 Mr. Darwin and Dr. Baird* both regard this organ, on account of 

 its structure and position, as the penis, in support of which it may 

 be remarked, that Mr. Darwin observed that this pair of legs was 

 frequently moved and retained irritability longer than any other 

 part of the body, which appears to indicate them as the seat of 

 some important function, which can hardly be any other than 

 that we have assigned to them, more especially as the female or- 

 gans of generation in other animals are most retentive of irri- 

 tability. The penis in all Cirrhipeds is also ringed. 



Neither Dana nor Milne-Edwards have noticed any organ 

 similar to this in any of the neighbouring genera ; so it is pro- 

 bable that in them it is not so much developed. 



Abdomen (figs. I & 11) is four-jointed in the male and two- 

 jointed in the female, and, like that oiPontella, &c., gives ofi" two 

 caudal lamella, each provided at the end with a few long plu- 

 mose hairs. 



The anus is, I believe, situated between the lamellae, as I have 

 traced the intestine thus far, and Mr. Darwin noticed its peri- 

 staltic motion in the abdomen. 



* Both of whom have very kindly given mc the benefit of their adviee in 

 drawing up this paper. 



