Dr Johnston on the genus C aligns of Leach, 
who has examined the whole group, which I have had no op- 
portunity of doing. I may be permitted just to remark, that 
the character “ a^itenn^E setaceoef admitted into the definition 
of the genus by Muller, Latreille, and Lamarck, seems to me 
altogether inapplicable to the species before us. The antennas 
are situate at the extremities of the anterior portion of the cly- 
peus, which bears the eyes, and which might properly be termed 
the frontlet. They are very short, round, somewhat thickened 
outwards, and their parts furnished with two (Dr Leach says 
one) unequal setae, and a few very minute hairs. The mar- 
gins of the clypeus are not ciliated, as Muller says those of his 
O, curtus are, but surrounded completely by a very delicate 
transparent membrane. The celliform bodies on the dorsum of 
the clypeus, whatever opinion may be formed concerning their 
nature or use, afford surely a character of too great importance 
to be overlooked ; and yet they are omitted by all the authors 
above cited, and even in the figures of Leach. Nor have the 
membranaceous lamellae, fringed by large pectenated setae, simi- 
lar to those of the six pair of legs, (see Leach’s figure), and 
placed beneath at the inferior angle of the clypeus, been observed 
by any but by Dr Leach, who, however, says there is one only, 
while in all our specimens, male and female, there are two on 
each side. It is not a little singular, too, that neither Muller 
nor Leach should have met with specimens bearing ovaries. 
Risso had observed them on the C. productus ; but, as far as I 
know, none but myself has seen them in any other species. 
Miiller believed that the eggs were produced in the jointed pro- 
cesses, and hence named them ‘fdamenta ovipara f and 
though this opinion is now proved incorrect, yet, since they are 
peculiar to the female, one cannot but conjecture that their 
function has some relation to the production or aerifaction of 
them. Dr Leach’s figures of the legs in the Supp. Encycl. Brit 
PI. XX., are very accurate. I am. Sir, your most obedient ser- 
vant, 
George Johnston. 
