27$ Mr. Macartney’s Observations 
a lens, it is readily perceived to be composed of a great 
number of very minute parts or lobules closely pressed 
together. Around these oval masses, the interstitial sub- 
stance of the corcelet is arranged in a radiated manner, and 
the portion of the shell that immediately covers the irradiated 
substance, is in a certain degree transparent, but less so than 
that which lies over the oval masses, it is therefore probable, 
that the interstitial substance in this situation, may be endowed 
with the property of shining. A fasciculus of the muscles of 
the corcelet arises in the interior of the oval masses of the 
luminous substance, but not apparently with any design, as it 
contributes, with the adjacent fasciculi, to move the anterior 
feet. 
In the elater ignitus, the masses of luminous substance are 
extremely irregular in their figure : they are situated nearly 
at the posterior angles of the corcelet, and are more loose in 
their texture than the oval masses of the noctilucus, re- 
sembling rather in composition, the interstitial substance 
which surrounds these masses in that species. The shell of 
the corcelet is somewhat thinner, and more transparent along 
both sides of the margin, than at other places, but it is not, as 
in the noctilucus, elevated, and peculiarly clear and thin im- 
mediately, over the seat of the luminous organ ; consequently, 
the light emitted by the elater ignitus, cannot be very brilliant. 
I have not been able to procure any specimen of the elater 
phosphorea, but from the accounts of naturalists, it appears to 
resemble in every respect the elater noctilucus ; indeed I 
have great doubts of the phosphorea being a distinct species. 
I have had an opportunity of examining, preserved in a 
moist way, two species of fulgora, the Candelaria and lanter- 
