1887.] G. M. Giles — Six new Am;phipods from the Bay of Bengal, 219 



with two smaller, serrations. The 7th and 8th are alike in all respects, 

 save size, the hinder being the larger. With the exception of the 

 short triangular ischiopodites, all the joints are cylindrical. The longer 

 of the two barely equals the abdomen in length. In both the dactylopo- 

 dites are minute and hair-like. 



The abdomen is slightly shorter than the thorax, the segments 

 diminishing in length from before backwards. The anterior extremity 

 of the first segment, where it joins the thorax, is much constricted, the 

 broadest part of the region being across the second segment. The last 

 three segments together barely equal the third in length. 



The three anterior abdominal appendages are of the usual type, the 

 middle one being the largest and the hindermost, the smallest. The 

 fourth consists of a cylindrical basal joint nearly as long as the third 

 abdominal segment. It is provided with two lanceolate entire-margined 

 rami, the outer of which is slightly the larger. The fifth is represented 

 only by a short bud-like rudiment. The last closely resembles the 

 fourth, but is somewhat shorter, and its rami are equal. 



The telson is rudimentary. 



A single specimen measuring about 7 mm. in length. 



§ 2. Rhabdosoma investigatoris, n. sp, PI. IV. 



This species presents a close resemblance to B, whitei and B. 

 armatum, forms which have recently been demonstrated to be male and 

 female of one species by Glaus,* by whom, as also by J. H. Streets,t they 

 are well described. The two must accordingly now stand as B. armatum 

 (Milne-Edwards). 



After comparing the present species with the above descriptions, 

 I am inclined to think that it is a distinct form, more especially as 

 the animal was obtained, although at some distance from the land, 

 from the shallow muddy water about the Palmyrus shoals. Still, the 

 resemblances are so numerous that the shortest way of describing the 

 new species will be to enumerate the differences from the above quoted 

 descriptions of B. armatum. 



Two specimens, one male and the other female, were obtained^ 

 the latter being that shown in the figure. It is probably an adult, as 

 the brood-pouch, although empty, is well-marked and of considerable 

 size. 



The differences, described from the female as the more complete 

 specimen, are as follows. — 1. The head is shorter, not equalling (rostrum 

 included) one half the total length of the body. 2. The mandibular 



* Arbeit, aus d. zool. Insfc. d. Univ. Wien. u. d. zool. Stat. Triest, 1879, II, 2. 

 t Proc. Acad. Sc. Phil., 1878, pp. 287—290. 



