PHYLLOCARIDA. 291 
‘The series of Amphipods begins with Cyamus ceti (Linn.), 
the whale-louse, passes into Caprella, with its linear body 
and spider-like legs, to Hyperia, which lives as a mess-mate 
of the jelly-fish, Cyanea, and culminates in the water-flea 
(Gammarus ornatus Edwards) and sand-flea (Orchestia agilis 
Smith), abundant and leaping in all directions from under 
dried sea-weed at high-water mark. 
— = 
Fig. 259.—Nebalia bipes. Enlarged 6 times. 
Order 5. Phyllocarida.—This name is proposed for a 
group of Crustacea, the forerunner of the Decapoda and 
hitherto regarded as simply a family (Medaliade), in which 
there is an interesting combination of Copepod, Phyllopod, 
and Decapod characters, with others quite peculiar to them- 
selves. The type is an instance of a generalized one, and is 
very ancient, having been ushered in during the earliest Si- 
lurian period, when there were (for Crustacea) gigantic forms 
(Dithyrocaris was over one foot in length) compared with 
those living at the present day. The order connects the 
Decapods with the Phyllopods and lower orders. The mod- 
ern Nebalia is small, about a centimetre (.40-.50 inch) in 
length, with the body compressed, four of the abdominal 
segments projecting beyond the carapace, the last abdominal 
segment bearing two large spines. There is a large rostrum 
overhanging the head ; stalked eyes, and two pairs of anten- 
nz, the second pair nearly as long as the body and many- 
jointed. The mandibles are succeeded by two pairs of max- 
