174 



in the East Indian Archipelago, Bet. indicus differs at first sight by the characters of the frontal 

 margin. While in the New Zealand species the front is deeply emarginate, "notched about as 

 deep as the eye-sockets" (G. M. Thomson, in: Trans. Linnean Soc. London, 1903, p. 438, PI. 28, 

 Fig. 1), the frontal margin appears in Bet. indicus very slightlye marginate; the notch 

 or emargination is concave at the base, not angular. The orbital hoods that are rounded 

 above, are separated from one another by a s h a 1 1 o w triangular groove and are marked each 

 with a fine suture, that runs from the antero-internal angle of the hoods, along their inner side, 

 backward; the two sutures unite at the base of the eye-hoods and extend as a very narrow, 

 linear, median groove or suture backward on the gastric region to a little beyond the anterior 

 third of the carapace. The distinctly facetted, grayish corneae are almost entirely covered by 

 the carapace, hardly projecting beyond the frontal margin when looked at from above ; in a 

 side view, however, they slightly extend beyond it. At the antero-internal angle of the corneae 

 the ophthalmopods are produced forward from under the frontal margin of the carapace and 

 armed each with a strong, acute, triangular tooth which is directed forward and 

 laterally compressed, appearing slightly concave at the inner, slightly convex at the outer side; 

 these produced parts of the ophthalmopods are rounded at their inner side and separated from 

 one another by a triangular notch, at the bottom of which one observes a small, acute, median 

 tooth, apparently the "bec ocellaire" of Coutière. Frontal and antero-lateral margin of the 

 carapace devoid of spines or teeth, pterygostomian angle rounded. 



The pleura of the second abdominal somite are very broad, those of the sixth subacute, 

 not articulate. When Thomson's figure 2 (1. c.) of the telson is exact, Bet. indicus proves 

 to differ especially by the spinules of the upper surface being placed nearer to the lateral 

 margins. The telson, as long as the 6 th somite, is 4,5-times as long as the posterior margin is 

 wide ; posterior margin as in Bet. aequimauus, the outer angles appearing dentiform ; proportion 

 between the width at the base and that of the posterior margin 2,8. The spinules of the 

 anterior pair are 0,22 mm. long, one-tenth or one-eleventh the length of the telson, and are 

 placed just before the middle, the proportion between the length of the telson and the distance 

 of this pair from the posterior margin being 1,9; the posterior pair is a little farther distant 

 from the anterior pair than from the extremity of the telson. The outer spine of the basal 

 joint of the 6 th pleopods is acute, depressed, large and reaches as far as the posterior pair of 

 spinules on the upper surface of the telson ; outer uropod almost twice as long as the telson, 

 the inner but very slightly shorter. 



Antennal region nearly as in Bet. acquimanns. Second antennular article almost as 

 thick as long and hardly more than half as long as the visible part of the first ; third almost 

 one and a half as long as the second ; anterior margin of the first and of the second article 

 beset with very small spinules. The outer flagellum is composed before bifurcation of 8 articles 

 which are all very short, much broader than long, excepting the first that is twice as long; the 

 two flagella are subequal and as long as the carapace. The stylocerite is acuminate and almost 

 reaches to the apex of the second antennular article. 



Spine at the infero-external angle of the basicerite triangular, acute, compressed, reaching 

 almost to the apex of first antennular article. Carpocerite stout, extending beyond the antennular 



42 



