200 CARL BOVALLIUS, AMPHIPODA HYPERIIDEA. I. 2. HYPERIID.E. 



Hyperia bengalensis. 



Colour. "The greater part of the surface of the body and appendages is liberally besprinkled with 

 patches of black pigment, so that, seen in the water, they appeared of a dark reddish 

 grey tint. The pigmentation is deepest on the pleura of the thoracic segments, on the 

 basipodites of their appendages, and on the abdomen. » (Giles.) 



Length. »2,5 mm.» (Giles.) 



Hal). The tropical region of the Indian Sea: »the Bay of Bengal. » (Giles.) 



Syn. 1887. Lestrigonvs bengalensis, G. M. GILES. 



»On six new Amphipods from the Bay of Ben- 

 gal'). Journal of the Asiatic Society of Bengal. 

 Vol. 56. Part 2, n:o 2, p. 224, pi. 6, fig. 

 1—10. 



The description of Giles does not give many characteristics useful for the defini- 

 tion of his species, but contains some statements which, if they are not due to mis- 

 observation, are entirely new, and important for our knowledge of the phylogenetic rela- 

 tions of the Hyperids. He says for instance that the last ural segment is nmited without 

 suture to the short, accurately semicircular telsow>; and that the second and third ural 

 segments are free, not coalesced. The latter feature is not improbable because it is known 

 to exist in the genus Vibilia, where some species have the segments in question free and 

 others have them coalesced. The former statement on the other hand I am much inclined 

 to think may be due to an erroneous observation, as I have myself often found the telson 

 in species of Hyperia and allied genera to be very thin, and perfectly hyaline, so that 

 it may easily escape observation when examined in the microscope by transmitted light. 

 I have also found that in many species the middle part of the hind side of the last ural 

 segment projects more or less to give support for the articulation of the telson. I may 

 venture the supposition that Giles saw and delineated such a projection — which naturally 

 is united without suture to the last ural segment — instead of the true telson. Also the 

 statement that the second pair of uropoda are longer than the third pair seems to need 

 corroboration, as such a fact is not known from any other species in the whole tribe. 



As it is figured by Giles the species is easily distinguished from its allies by the 

 length of the carpal process of the second pair of peraeopoda. 



From his description I quote the following passages: 



»The head is the broadest portion of the animal, the two immense eyes projecting consi- 

 derably beyond the very narrow thorax when seen from above. » 



»The eyes are of large size and distinctly faceted, the anterior faceted membrane being 

 easily separable, and they cover the entire upper and lateral aspects of the head, the anterior 

 aspect of which is deeply excavated for the reception of the antennas. » 



»The thorax is composed of seven distinct, but very short, segments; die junction between 

 the pleura and the coxal plates being hard to make out, as also are the junctions of the terga 

 of the first 5 thoracic segments. The segments increase in length slightly from before backwards, 

 but not to any very marked extent; the entire thorax forming less than a third of the entire 

 length of the animal. » 



