
23 
Notes from the Museums and the Aquarium. 
Parasitic Crustacean on a Flying-Fish.—In May, 1896, there was 
presented to the Museum, by Captain Hearn of the sailing ship ‘ Genista,’ 
a specimen of the Flying-Fish, Exocetus volitans, about eight inches in 
length, accompanied with the information that it had flown on board his 
ship in the South Pacific Ocean. It was remarkable for having two fish- 
lice hanging down from the ventral surface, each of which was, in turn, 
covered by a colony of small Cirripeds. The fish-lice proved to be females 
of the parasitic Copepod, Penella blainvillii, the species apparently peculiar 
to Exocetus. They were attached, as may be seen in the figure, to the 

Penella parasitic on Exocetus. 
ventral surface of the fish, one on each side of the middle line, about three- 
quarters of an inch anterior to the base of the pelvic fins, the right Penella 
being slightly in advance of the left. On making an incision into the 
abdomen, it was perceived that both parasites penetrated the entire 
thickness of the body-wall, each having its head buried in a mass of soft 
tissue, which together completely filled the coelomic cavity, from side to 
side, at the point of insertion. It was found also that the entire cavity in 
front and behind this double mass of soft tissue, was completely empty. 
No trace of an alimentary canal or of other viscera, with the exception of 
the heart, was present; the masses of loose tissue investing the heads of 
the parasites alone occupying the cavity. 
