REPORT ON THE AMPHIPODA. 1549 



guathopods straight, the upper antenna like those figured by Claus for the female of 

 Thamyris globiceps, and the telson with acute-angled though not outdrawn apex. 



A' species of this genus from " Ocean Beach, Dunedin," New Zealand, of which 

 Mr. G. M. Thomson very kindly sent me detailed description and figures, is in the closest 

 relationship to the specimen B here described, but with the head less rounded and the 

 telson "acutely triangular." The differences between specimen A and specimen B 

 consist chiefly in the shape of the head, the form of the first joint in the first gnathopods, 

 and the more or less rounding of the apex of the telson. The first and third of these 

 may, I think, be attributed to individual variation, the remaining and the most striking 

 difference I have, after much hesitation, assumed to be a character of age and sex. The 

 specimens with the strongly twisted joint have the antennae of the adult male, those in 

 which it is slightly twisted have the lower antennae incompletely developed, and female 

 specimens have only a suggestion of the twisted first joint. Spence Bate's figure of 

 Brachyscelus crusculum $, Glaus' figures of the gnathopods of Thamyris mediterranean 

 young male, and Thamyris rapax $, as well as Mr. Thomson's figure of the male 

 specimen from New Zealand, all lend support to the supposition that in this genus the 

 strongly twisted arm of the first gnathopod is a character only of the adult male. 



Brachyscelus insequipes (Dana ?). 



1852. Daira insajuipes, Dana, U.S. Explor. Exped., vol. xiii. pt. ii. p. 993, pi. lxviii. 



figs. 5 a-c. 

 1862. Dairinia in&quipes, Spence Bate, Brit. Mus. Catal. Amph. Crust., p. 310, pi. 1. fig. 6. 

 1887. Thamyris insequipes, Bovallius, Systematical List of Amph. Hyper., Bihang till K. 



Svensk. Vetensk.-Akad. Handl., Bd. 11, No. 16, p. 31. 



A specimen with large head and great eye-pigment, a single pair of slender straight 

 antennae, in which the third joint is longer than the second or fourth, the mandibles 

 without palp, the first joint of the first gnathopods not twisted, and the front process of 

 the wrist not much produced, the lower margin of the first joint in the fourth peraeopods 

 produced below the second joint, the first joint of the fifth peraeopods not so dilated as 

 in the other two species here described, the telson narrower than in those species, apically 

 almost acute. 



Of the Mandibles one has a secondary plate with finely denticulate edge, resembling 

 the principal plate but smaller, while the other has a spine-like process like that described 

 for Brachyscelus crusculum ; in each mandible the principal cutting edge has a minute 

 tooth at the lower end and a larger obtuse one at the upper ; the upper lip is broader 

 than deep, embracing the distal triangular ends of the two mandibles. The mouth organs 

 probably in all essential respects agree with those of the other species. 



Locality. — Februaiy 6-7, 1875, south of Mindanao, Celebes Sea; lat. 6° 20' N., 



