APPENDIX. 523 
THEMISTO CRASSICORNIS, 
Specific character, Superior antennse very short, thick, biarticulate, fur- 
nished along their under surface with numerous auditory cilia; inferior antenne 
with a flagellum composed of one short and one long joint. First two pairs 
of pereiopoda having the carpi subovate, smooth, and unarmed along the 
inferior margin. 
Length, half an inch. 
Themisto crassicornis. Kroyer, Grénl. Amfip. p. 67, pl. iv. fig. 17. 
Epwarps, Hist. deg Crust. t. iii. p. 85. Spence 
Bars, Cat. Amph. B. M. p. 818, pl. i. fig. 12. 
Tue first two segments of the pereioneare shorter than the 
rest, which are subequal. The superior pair of antennee have the 
peduncie short, the flagellum uniarticulate, curved downwards 
at the extremity, and furnished along the inferior margin, for 
about two-thirds of its length, with auditory cilia. The inferior 
pair consist of a peduncle, of which two segments are visible, 
and a long slender multiarticulated flagellum. The first pair 
of gnathopoda are very short, not having the carpus anteriorly 
produced. The second pair of gnathopoda are not larger than 
the first, but having the inferior angle of the carpus anteriorly 
produced. The first two pairs of pereiopoda resemble each 
other; the second pair is slightly the larger, having the 
meros and carpus broadly distended, the latter fringed along 
the inferior margin with a row of very fine short cilia, and a 
few long equidistant solitary hairs; propodos and dactylos 
reduced in character to abiarticulate joint, that bends back to 
form a prehensile organ with the carpus. The third pair of 
pereiopoda are very long, quite as long again as the next suc- 
ceeding pairs, having the propodos and carpus subequal in 
length, and the former furnished on the anterior margin with 
a comb-like row of fine teeth; dactylos short and slender. 
The two last pairs of pereiopoda are about half the length of 
the third pair. The posterior pair of pleopoda is long and 
simple. The telson is short and dorsally flat, having a central 
process on the under surface that lies between the basal joints 
of the posterior pair of pleopoda. Colour, orange. 
This species has been recently sent to us by Mr. Edward, 
who has taken several of different ages off the coast of Banff. 
