is a rudimentary secondary appendage only about half as long as the first joint of the flagellum. Peduncle of lower antenna equal in length to that of the upper, the last two joints equal in length. Appendage of the mandible three-jointed, the second joint larger than the first, the third short and curved. Second gnathopoda more slender than the first. Last three pairs of pereiopoda increasing in size from before backwards, the various joints being pretty abundantly supplied with stout setæ. Last three pairs of pereiopoda slender, biramous, the penultimate the smallest and having the rami slightly unequal, the rami in the other two being equal. Telson short, as long as broad, the posterior border slightly concave.

Male.—Differs in having sensory capsules and setæ on both pairs of antennæ, and in having the gnathopoda much larger than those of the female. First pair of gnathopoda much larger than the second, propodos very large; palm broad, defined by one long and two short spines, the long one being about two-thirds the length of the finger. Second pair much smaller, palm defined by a short, stout spine. Colour-transparent.

Length of female (with eggs), .3 inch. Male (largest specimen), .5 inch.

Hab. Pump at Eyreton.

This species differs from the other species of Calliope in the absence of eyes and in the presence of a rudimentary secondary appendage on the upper antenna, but I have not considered this sufficient to warrant its removal from the genus. The female is very abundant, but the male is rarely obtained.

The number of joints in the flagella of the two antennæ varies very much (in the female) according to the size and therefore presumably according to the age of the animal. Thus in very small specimens I found 15 joints in the flagellum of the upper antenna and 7 in the lower, while in full-sized specimens there were about 55 in the upper and 21 in the lower.

In the male, peculiar “sensory capsules” are found on both antennæ. They are to be found on the last two joints of the peduncle and on the proximal half of the flagellum of the upper antenna; on the distal half simple sensory setæ (fig. 4 b) are found on every other joint. The sensory capsules are also present on all the joints of the flagellum of the lower antenna except the last two or three. They are cup-shaped and slightly constricted towards the middle, and they are situated on a slight protuberance of the joint of the flagellum (fig. 4 a). On the peduncle of the upper antenna of the male there are other peculiar-looking setæ which are evidently sensory. They are long and slender, with several very fine divergent filaments at the distal end (fig. 3). Similar capsules and setæ