220 G. M. Giles — Six new AmpM^ods from the Bay of Bengal. [No. 2, 



palp is longer, exceeding in length considerably the first joint of the 

 inferior antennae. 3. Spence Bate (Cat. AmpMpodous Crust. Brit. Mus. 

 1862) describes B. whitei as " having the coxa of first pair of gnathopoda 

 produced to an obtuse point " : this is wanting in our species. 4. All 

 three of the authorities agree in describing considerable differences 

 between the 1st and 2nd gnathopoda in size, length, and formation : 

 in the present species these are subequal and very closely resemble 

 each other. 5. Spence Bate describes the pereiopoda (last 5 thoracic 

 appendages) as gradually increasing in length posteriorly, the fourth 

 pair longest, the fifth obsolete. In our form, the third is longer than the 

 fourth, aud the fifth, although either obsolete or destroyed in the male, is 

 represented by a club-shaped basipodite in the female. 6. The same 

 writer also gives the last three abdominal appendages as differing con- 

 siderably in length, the last being the longest, while in our form they are 

 subequal, the first being a trifle the longest. 



Length of male 2'5 c. m., of female 4*9 c. m. 



The male differs further in the inferior antennae being much shorter, 

 and the mandibular appendage correspondingly diminished. 



I append a table of measurements from Claus of B. armatuni ; and 

 a comparison of the corresponding measurements of the present species 

 in an adjacent column is, I think, alone sufficient to establish the specific 

 distinctness of the two forms. The measurements are in millimeters. 



B. inveati- 



R. armatum. 



gatoris. 



Length of rostrum (broken) .... 



,, „ head 



„ „ thorax 



,, „ 3 anterior abd. segs. 



„ „ 4th abd. seg 



„ „ 5th & 6th abd. segs. 



„ „ telson 



„ „ 1st caudal style 



„ ), 2nd „ „ 



« 3rd ,, „ 













■» 



- 



cf 



c^ 



cf 



cT 



"i 



¥ 



cf 1 



15 



18 



20 



36 



24 



28 



4^ 



6i 



8 



8 



9 



10 



11 



4i 



6f 



9 



9 



9 



9^ 



11 



4 



n 



9i 



. 9i 



10 



10 



12 



5 



^ 



4 



3f 



2i 



3 



3i 



2} 



3i 



4i 



4i 



3^ 



4 



5 



2 



6 



9 



8 



10 



18 



23i 



3i 



6 



8 



7* 



8 



10 



11 



3^ 



4i 



4i 



5* 



3 



— 



4 





6 



8 



7i 



9 



— 



18 



— 



? 



10 

 8 

 7 

 7 

 3i 

 3i 

 6 

 51 

 5^ 

 5i 



In the male specimen of our species the rostrum is very much 

 broken, in the female it is nearly complete. The specimens are preserved 

 in the Indian Museum. 



§ 3. Amphipronoe longicoenuta, n. sp., PI. V. 



Three specimens of the small amphipodous crustacean to be de- 

 scribed below were taken in the drift-net in the clear but shallow water 

 of the Mergui Archipelago. 



It probably has its proper habitat at the surface, as it swims easily, 



