with Modern Representatives. 



389 



the others being distinct and bearing each its own separate tergum and 

 serial paired appendages, similar to those of the succeeding abdominal 

 somites, the head being no larger than in an Amphipod (which latter 

 it also somewhat resembles in the general form of its body). The eyes 

 are not clearly preserved in the fossil, but they appear to have been 

 borne upon a short penduncle close to the base of the antennules. 

 These antennules were supported upon three stout basal joints, and 

 carried a long outer and a shorter inner flagellum ; the antennce support 

 on their distal joint an elongated, setose, rounded scale and a single 

 stout flagellum. Of the mouth appendages there is no evidence in 

 the fossil, but the second thoracic (the first free segment) no doubt 

 carried a pair of maxillipeds, as they differ in being stouter and broader 

 distally at the fourth or fifth joints than those which follow, and consist 

 only of an endopodite or walking limb (or a simple claw-like organ?). 

 Four, at least of the six appendages which follow are true Schizopod 

 limbs, having a well-developed, setose, many-jointed exopodite attached 

 to each leg (the endopodite), and probably also carrying branchial 

 lamellae on their basal joints. 



The two hindmost pairs of thoracic limbs may not have been 

 provided with exopodites. The five abdominal segments following bear 

 true bifid swimming-feet (multi- articulate and setose) ; the sixth segment 

 is longer and more cylindrical, and bears on each side, upon its distal, 

 lateral extremity, two rounded, scale-like uropods, or swimming organs, 

 resembling the lateral lobes of the tail-fin in the Macroura, and 

 a rounded central telson or terminal joint. 



Allied Fossil Geneea.^ 



1. Gampsonyx fimlriatiis, Jord. & v. M. — A form was described under 

 this name by Jordan & von Meyer in 1854^ from the Coal-measures 



Fig. 6. — Gampsonyx fimhriatus, Jordan & v. Meyer. Pernio - Carboniferous : 

 Saarbriick, Rbenish Prussia. Drawn from Jordan & v. Meyer's plate in the 

 FalcBontographioa, vol. iv (1856). 



1 The three forms referred to here have been discussed by Dr. Packard and form 

 his groups Syncarida and Gampsonychidae (American Naturalist, vol. xix (1885), 

 pp. 790-2; Mem. Nat. Acad. Sci., Washington, vol. iii (2), 1886; Proc. Boston 

 Soc. Nat. Hist., vol. xxiv (1889); see also Packard's "Textbook of Zoology," 

 5th ed., 1886. He here uses the term Sjmcarida as including Gampsonyx, Acantho- 

 telson, and Talceocans. Dr. Caiman has also figured and noticed them in his memoir 

 on Anaspides (see Trans. Roy. Soc. Edinb., 1896, already quoted). The figures 

 of these here given are reproduced from Dr. Packard's restorations. 



^ " TJeber d. Steinkohlenformation von Saarbriicken " : Falceontographica, vol. iv 

 (1856). 



