REPORT ON THE AMPHIPODA. 1485 



Telson reaching as far as or a little beyond the apex of the inner ramus of the third 

 uropods, the apex without setules. 



Localities.— April 28, 1876, North Atlantic; lat. 17° 47' N., long. 28° 28' W. ; 

 surface, night ; surface temperature, 73°. One specimen, male. 



April 29, 1876, North Atlantic; lat. 18° 8' K, long. 30° 5' W. ; surface; surface 

 temperature, 74°. Four specimens. 



Remark. — A specimen of this species has been sent me by Dr. Bruce from Malta. 



Genus Amphithyrus, Claus, 1879. 



1879. Amphithyrus, Claus, Die Gattungen und Arten der Platysceliden, p. 15. 



1886. ,, Gerstaecker, Bronn's Klassen und Ordnungen, Bd. v. Abth. ii. p. 483. 



1887. „ Bovallius, Systematical List of Aniph. Hyper., Biliang till K. Svensk. 



Vetensk.-Akad. Hand!, Bd. 11, No. 16, p. 48. 

 1887. „ Claus, Die Platysceliden, pp. 31, 41. 



For the original definition of the genus, see Note on Claus, 1879 (p. 491). In the 

 preliminary table of the family Typhidse, Claus gives as the character common to 

 Tetrathyrus and Amphithyrus : — 



" Both pairs of gnathopods subchelate. The two terminal joints of the hinder antennae 

 in the male as long or nearly as long as the preceding." 



To distinguish Amphithyrus from the companion genus he gives the characters : — 



" Gnathopods doubly and complexly subchelate. The laminar first joint of the sixth 

 pair of legs [Fourth Perseopods~\ with large pocket-shaped groove." 



Amphithyrus orientalis, n. sp. 



For the appearance of this species both in general form, and with certain exceptions 

 also in detail, I may refer to the figures given by Claus in Die Platysceliden, Taf. vii., of 

 his species Amphithyrus sculptwatus from the Atlantic Ocean. It is also in general 

 shape like Parascelus zebu of this Beport. The head is a little produced below ; the 

 postero-lateral angles of the first three pleon-segments are not acute, and the fourth pleon- 

 segment has a well-marked dorsal depression. 



Upper Antennse. — First joint of the peduncle widening distally, second and third 

 joints very short, scarcely distinct in parts of the circumference ; first joint of flagellum 

 large, strongly bent, with a large brush of long filaments fringing the long convex margin 

 and passing right round the produced rounded apex ; the second joint not reaching beyond 

 the apex of the first, tapering distally, its outer margin convex, carrying five groups of 

 broad filaments ; the third joint not longer than the second, much more slender, with 

 two groups of long filaments on the outer margin ; the fourth joint slender, spiniform. 



