HERMAPHRODITE. 267 



Upper Latera, internally flat, oblong, twice as long as 

 broad ; upper end square, truncated ; upper half rather 

 wider than the lower half; fully twice as large as either 

 of the lower latera. The basal points extend below the 

 basal margins of the scuta. The umbo is placed a little 

 above the centre. 



Rostral Latera, minute, scarcely exceeding one third 

 of the size of the carinal latera, and very much less than 

 the rostrum; they are placed transversely under the basal 

 point of the upper latus, or rather between it and the 

 baso-lateral angle of the scutum ; basal margin, as seen 

 internally, straight ; upper margin arched ; rostral angle 

 produced ; internally flat ; the whole valve is very thick 

 and solid, so that the umbo which lies at the rostral end, 

 projects rectangularly outwards. 



Carinal Latera, oblong, nearly quadrilateral, with the 

 upper angle produced; placed obliquely, parallel to the 

 lower half of the upper latera ; umbo slightly prominent, 

 seated near the apex, with three rounded ridges proceed- 

 ing from it ; internal surface very slightly concave. 



Peduncle and Attachment. — The peduncle is short, not 

 equalling the capitulum in length. The whole surface is 

 most thickly clothed with minute spines, which are 

 not visible when the specimen is dry ; I think it pro- 

 bable that they may sometimes all drop off" before a new 

 period of exuviation. The peduncle does not (at least 

 in the specimens which I have examined, which were 

 grouped in a bunch) taper at the lower end to a point ; 

 and after careful examination, I feel sure that the cement 

 does not debouch from several successively formed orifices, 

 as in jS. vulgare and as in some Pollicipes, but only 

 from the two original orifices in the prehensile antennae 

 of the larva. In these latter organs, the sucking disc is 

 hoof-like and pointed, and is narrower than the basal 

 segment. The ultimate segment has on its inner side 

 (supposing this segment stretched straight forwards,) a 

 notch or step bearing at least three spines. The pro- 

 portions of the different parts differ slightly from those 



