30 T. V. HODC.SOX. 



The pleopodii arc four paired strmturt's orciipyinf^ the ciitiio area Itolow the laiulal 

 sliirltl. ivuli plcopod consists of a very luoad aixl short Imsal joint bearing an 

 cxopoditc and an cnihipodite, \vhi<h lie ovt-r one another, the exopodite licing the outer 

 or more ventral structure.. The exopodite of the first gill is the largest and coarsest 

 in structure, forming an opcnuliini <iver the rest. The plate is obliquely divided into 

 two by a suture, and it« stout straight inner margin is thickly fringed with fine set«; ; 

 the outer margin, which is rounded anteriorly and wide, tapers slowly to a blunt point 

 and is fringed with rather long plumose setai. The endopodite is much more delicate, 

 rather smaller, having no setae whatever, and it is not divided, though its outer margin 

 bears a conspicuous notch wliere the division should be. The posterior gill is shorter 

 and broader than the preceding one ; the exopodite is obliijuely divided, but the cmly 

 setae it bears are a few of both kinds at the distal extremity ; the endopodite resembles 

 that of the fii-st gill. 



The uropoda are attached to the caudal shield where the edge becomes dentate ; 

 the basal joint is short, expanded distally, and prolonged on the inner side into a 

 spinous process. The exopodite is two-jointed, the terminal one being scarcely half as 

 long as the other, pointed, and having two serrations on the outer side and two spines 

 on the other. The endojiodite is a little longer than the first joint of the exopodite, 

 and its external margin is serrate and has a few seta; in addition ; the internal margin 

 is also serrate but onl}' distally. 



Two males and fragments of two others, sex uncertain, were taken by the 

 ' Discovery ' in lat. G7° 21' 46" S., long. 155° 21' 10" E., 254 fathoms, lujttom mud. 

 The trawl passed over a patch of stones probably dropped by some wandering iceberg, 

 ami ])rouglit up so large a (quantity of these that the specimens were very severely 

 damaged, and the trawl had to be slit up completely to save anything. 



Both Dr. Studer's and Mr. Beddard's descriptions of Siivlis cornutn are defective 

 in many points. The niceties of specific discrimination as now understood were 

 altogether unknown in Eights' day. Almost invariably the defects of previously 

 publi.shed descriptions are those of omission rather than commission, and going through 

 them exhaustively with the ' Discovery ' specimens before me, I have no hesitation what- 

 ever in definitely stating that the ' Gazelle ' and ' Challenger ' specimens are immature 

 specimens of Serolls trilobitoides Eights, and that the ' Discovery ' specimen is only 

 just arriving at the adult stage. 



CWMUDUCELL.V. 

 PfetTir (.11), pp. 10'.)-110 ; Hansen (7), p. 107. 



The following definition of this genus is ]>y Dr. Han.scn — 

 Both .sexes .similar without processes. 



Distal i)art of the alxlomen somewhat produced, with the lateral walls iicnt 

 strongly downwards and inwards, constituting rather a long tube open 

 at both cuds and with a .slit on the lower surface. 



