268 M.T. Thorell on the Systematic Position of the Argulide. 
finer texture, approaching that of the lower wings. The claws 
of the tarsi are strong, powerful, and well adapted for clinging. 
In this animal we seem to have a combination of two plans-of 
adhesion: there are the claws and claspers and flaps for hold- 
ing on by; there is the hollow underside for adhering by ex- 
hausting the air between it and the stone it clings to, on the 
principle of the air-pump. If, when it settles on the stone and 
adjusts itself, its trachez are full of air, and it then expels 
the air and by muscular power draws in the skin of the abdomen 
and underside generally, it must, of course, leave a vacuum, 
and consequently adhere like a sucker. 
‘This species from the mountains of Brazil is the only one of 
whose aquatic habits any account has been received; but the 
genus, although individuals are rare (as with most species which 
only show themselves at night), is widely distributed. 
The following are the species known up to the present time, 
with their localities, taken from Westwood’s recent Monograph 
of the Phasmidee :— 
Prisopus flabelliformis, Stoll. Brazil; Cayenne. 
—— spiniceps, Burm. Do. do. 
— Ohrimanni, Licht. East Indies. 
horridus, Westw. Columbia. 
Horstokku, De Haan. Cape of Good Hope. 
— berosus, Westw. Panama. 
— phacellus, Westw. Brazil; Ega. 
—— incertus, Westw. Samarang ; Java. 
— cornutus,G.R.Gray. India. 
— cepus, Westw. Bolivia. 
Guerini, Westw. Ile Maurice. 
Now that their habits are made known, we may expect that 
specimens will become less rare, and that we shall receive more 
information regarding their economy and mode of life. 
XXXV.—On Two European Argulide, with Remarks on the 
Morphology of the Argulidee and their Systematic Position, to- 
gether with a Review of the Species of the Family at present 
known. By T. THoreLu. 
[Continued from p. 169.] 
DET: 
As the question of the position which the family Argulide 
should occupy in the system of the Crustacea is far from having 
received a satisfactory solution, it will not be out of place here 
to dwell somewhat further on this subject. Referred by Linné 
