CCXXXIV 
APPENDIX. 
means remarkable either in this species, or in some others, which are dis- 
tributed by it into the respective genera of Talitrus and Gammarus ; if a sub- 
division be desirable in the well-defined and natural genus comprehending 
all these animals which so nearly resemble each other in general appearance 
and habits, the prolongation of the anterior part of the head into a rostrum, 
would seem preferable to a distinction founded on the relative length of the 
antennae, which in many of the species are so nearly the same ; or, the genus 
I 
Talitrus might be limited to those species in which the superior antennae are 
very short, not exceeding the length of the two first articulations of the in- 
ferior pair. 
This species has been named in compliment to John Edwards, Esq., 
surgeon of the Hecla. 
Talitrus Cyane^. 
T. capite obtusissimo, antennis subsequalibus, corpore latiore, pedibus quatuor anticis inunguiculatis. 
Plate 1, fig. 12 — 18. 
Parasitic on the Cyanea Arctica, the individuals varying in length from two 
to eight-tenths of an inch ; colour pale yellowish red, sprinkled with innu- 
merable minute spots of deeper red ; in about half the specimens, the num- 
ber of which was considerable, the antennae were equal in length to the five 
first segments of the body ; in the others, they were scarcely one-fifth as long, 
but otherwise similar ; there was no other perceptible difference in the spe- 
cimens. The two pair of antennae are so very nearly of the same length, that 
it has been by no means easy to decide whether the species should be con- 
sidered a Gammarus or a Talitrus ; those of an individual, however, in which 
the greatest disproportion existed, have been figured (fig. 14, 15, and 16,) for 
the purpose of justifying the ultimate decision; the remarkable conformation 
of the head will, doubtless, be considered by many naturalists as a peculiarity 
requiring the establishment of a new genus. 
Head rounded, and very obtuse ; eyes extremely large, lunate, of a brown- 
