70 SIR CHARLES ELIOT ON [May 6, 



oesopliagus, which is provided with a series of folds, but no hard 

 armature of any kind. The stomach is set with a belt of horny 

 plates of two sizes and usually alternating regularly, the small 

 being next to the large. The pyloiic portion of the stomach 

 below this belt is provided with musculai- lidges, and passes 

 almost imperceptibly into the intestine. At the point where it 

 begins to be constricted is a pouch-like diverticulum with a 

 laminated interior. 



With the exception of the absence of jaws, the other charactei's 

 of this animal clearly connect it with Melibe, not Tethys. The 

 foot is very nari'ow, the body rather high and compressed ; the 

 cerata are covered with knots ; the buccal opening passes straight 

 into the cesophagus ; the stomach is armed with plates ; the liver 

 is long and follicular and does not extend far into the cerata ; the 

 hermaphrodite gland is composed of many separate lobes at the 

 side and under the liver. In Tethys, on the contrary, the foot is 

 broad and the body flat ; the ceiuta are smooth ; there is a division 

 of the alimentary canal befoi-e the cesophagus which may be called 

 a buccal cavity ; the liver is a compact mass sending diverticula 

 to the ends of the cerata ; the hermaphi'odite gland forms a thick 

 covering over the liver. Furthei-, Tethys is described as possessing 

 true branchise set at the base of the cerata. The back of Melibe 

 fimhriata is covered with branched papillae which bear a superficial 

 resemblance to gills, but I could not discover that they have any 

 special connection with the vascular system, and they seem ana- 

 logous to the ramose appendages of Plocamophorus and some 

 species of Notarchus. 



It would thus appear that Melibe fimbriata is intermediate 

 between Tethys and the jaw-bearing species of Melibe. It does 

 not, however, seem necessary to create a new genus, but rather to 

 modify the existing descrij)tion of the genus and say jaws jn-esent 

 or absent. The shape of the foot, body, and cerata, the j)resence 

 of stomach-plates, the absence of branchise, and the character of 

 the liver distinguish it sufficiently from Tethys. 



In spite of its want of jaws, Melibe fimbriata is a most voracious 

 animal, and I more than once found in the stomachs which I 

 examined limbs of Crustacea more than an inch long. The way 

 in which it captures its prey is extremely curious. The circular 

 oral veil acts as a net with an elastic rim. When seeking for 

 food it expands the net and sweeps with it the surface over which 

 it is crawling. The skin of the hood is stretched so tight as to be 

 quite transj)arent and the marginal cirri are almost invisible. The 

 moment a small crustacean or other prey is caught the net closes 

 up, the cirri almost unite on the under surface, and the skin 

 ceases to be perfectly transparent. Then the Melibe tosses the 

 hood, which has now practically become a closed sac, backwards, 

 and creates a current of water with the cirri, which forces its 

 prey towards its mouth. The movements of the animal are rapid 

 and energetic, whether it crawls or swims. It can also float on 

 the surface foot vippermost. 



