222 G. M. Giles — Six neio Amjphipods from the Bay of Bengal. [No. 2, 



border comes to be directed upwards and forwards. Its convex border 

 is thickly clothed with a multitude of very fine, soft, flexible hairs, 

 regularly arranged in distinct, but closely placed, transverse rows. The 

 body of the joint is filled up by a large ganglionic mass, which appears 

 to send off branches to the bases of the hairs. The flagellum (Fig. 3.) is 

 extremely small in proportion to the peduncle, and consists of three 

 joints, subequal in length, compressed, and diminishing progressively in 

 breadth, so that the last joint is cylindrical ; the first joint is provided 

 with a circlet of soft clavate or spindle-shaped flattened hairs not so 

 long as, but considerably broader than, those of the distal joint of the 

 peduncles. The second has a similar pair of hairs springing from a de- 

 pression on its distal aspect, while the last joint, which presents two 

 slight constrictions in its length, is free from hairs, with the exception 

 of three stiff tapering auditory bristles at its extremity. The entire 

 organ is less than a millemeter in length and is so articulated as to be 

 capable of flexion and extension only, no lateral play being practicable. 



The antenna take their origin a little behind, but much external 

 to, the antennules, so that their first joint is placed close to the wall 

 of the recess, and, in their habitual posture, they are completely hidden 

 from the outside. The first joint reaches quite to the front of the recess, 

 so that, to the casual observer, the second appears to be the first joint 

 of the appendage, and to take its origin considerably in front of the 

 antennules. The 2nd, 3rd, and 4th joints are carried folded sharply upon 

 one another and the 2nd and 3rd of them are each half as long as the 

 animal exclusive of the last two abdominal segments ; the fourth is 

 slightly shorter and the fifth very short : the proportional length of the 

 5 joints being as 25 : 67 : 67 : 60 : 3 ; and the whole length of the organ 

 being a little over 9 m.m., or about \\ times the length of the body. 

 Each joint is thickly clothed with extremely fine short hairs, too small 

 to be visible except under very high amplification. The musculature of 

 their appendages is peculiar. In the first joint, a pair of powerful 

 muscles, flexor and extensor, are located in its proximal two-thirds, and 

 act by means of two distinct tendons on the second joint. In the re- 

 maining articulations, the muscles are confined to a small part of the 

 distal extremities, which are dilated for their reception, the muscles 

 in each case being in pairs so that no lateral motion is obtainable. 



The mouth-organs appeared to be very rudimentary, but were not 

 closely examined. 



The 2nd and 3rd thoracic appendages (gnathopoda) are short and 

 stout and can scarcely be made out in the usual position of the animal, 

 being carried folded closely against the ventral surface of the body. 

 They closely resemble each other, differing only in the more anterior 



