CCXXX1V 
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 
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 Cyanfje. 
T. capite obtusissimo, antennis subaequalibus, 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- 
