REPOET ON THE AMPHIPODA. 471 



inferior margins finely serrated, the third segment with the postero-inferior angle produced 

 into a long, spinous process, the angle of the first and second segments square behind, not 

 produced." Ciaus, on the other hand, for his species gives " die Seitenfliigel der Abdominal- 

 segmente unbewcaffnet," yet he figures the postero-inferior angle of the third pleon-segment 

 produced into a sharp point, the same angle on the two preceding segments being wel' 

 rounded. 



1877. Theel, Hjalmar. 



Eelation de I'expedition Suedoise de 1876 au Yenissei. Upsala, 1877. p. 33. 



" Gammarus xivlex found in lakes of the Tundra, near Doudino, Siberia, at 69° N. lat." (Dr. 

 von Martens, Zool. Eecord for 1877.) 



1877. Thomson, C. Wyville. 



The Voyage of the ' Challenger.' The Atlantic. A prelimiuary account of the 

 general results of the exploring voyage of H.M.S. ' Challenger ' during the year 

 1873 and the early part of the year 1876. Vol. I. London, 1877. 



There is but one passage specially referring to the Amphipoda (pages 129-132). On January 

 28, 1873, the trawl was employed successfully " at a depth of 1090 fathoms, about 

 90 miles to the south-east of Cape St. Vincent." " The trawl on this occasion contained 

 a single examjile of the female of a very large amphipod crustacean, briefly described under 

 the name of Cystosoma neptuni by Guerin-M^nevLlle from a single specimen obtained in 

 the Indian Ocean. We have since takeu several specimens at different stations in the 

 Atlantic ; and as a small male was in one case captured in the towing-net, there can be 

 little doubt that, like Plironima, to which genus it is allied, Cystosoma is a pelagic animal, 

 probably retiring during the day to a considerable depth, but occasionally coming to the 

 very surface of the water. The male example figured (Fig. 27), which is 103 mm. in 

 length, was taken in Lat. T 22' K, Long. 26° 36' W., a little to the east of St Paul's Eocks, 

 where the depth was 1500 fathoms. 



" The animal presents a very remarkable appearance. It is absolutely colourless and transparent, 

 so that by transmitted light the internal organs can be perfectly seen through the test — the 

 cephalic ganglion with the nerve-fibres running to the antennae and the eyes ; the ganglia 

 of the double ventral cord with the filaments passing to the appendages ; the heart, an 

 elongated tube with three openings ; the stomach, a large sac with a small intestine leading 

 from its base to the excretory opening in the telson ; in the female two large rose-coloured 

 ovaries, the oviducts passing to an opening covered by ivio small lamellae, at the base of the 

 first segment of the pereion ; in the male two elongated testes, their ducts opening between 

 the appendages of the seventh segment. 



" The head is large and greatly inflated, and its upper surface is entirely occupied by two 

 enormous facetted eyes, reminding one of the eyes of ^i/lina among trilobites. There are 

 two rows of spines along the lateral borders of the head, and some spines are placed round 

 the mouth, which is in the usual position at the base of the cephalic segment on the lower 

 surface of the body. The first pau' of antennae only are developed in either sex. The 

 antenna consists of two joints, and is attached to the anterior margin of the head. 



" The parts of the mouth and the maxillipeds are very small ; the two gnathopods are terminated 

 by claws as in the Typhids, and act functionally as second and third maxiUipeds. 



" The pereion consists of seven segments ; and the pleon of five, to the two last of which the 



