349 
Remarks. The species is sharply distinguished from St. pe- 
dunculatus by many characters, among which those enumerated in 
the conspectus are especially good and easily observed. 
Insufficiently described Species. 
Stylopauropus atomus Cook (Brandtia VI, 1894, p. 31). Cap- 
tured near Huntington, Long Island, U. S. According to the au- 
thor it differs from St. pedunculatus at least in the much smaller 
size, as mature individuals of both sexes are only *55 mm. long. 
No other real differences (only an imaginary one) are found in the 
short description, in which only the antennæ are mentioned, and it 
may be permitted to ask how this species can be recognized, if two 
or three small species of Stylopauropus live in North America? 
II. JPcturopus Lubbock, 1867. 
Diagnosis. The lower antennal branch has the anterior mar¬ 
gin at least slightly and generally somewhat shorter than the pos- 
terior, its anterior flagellum is shorter than the other, and the 
transverse diameter of the globulus is never shorter and generally 
much longer than its stalk. The penultimate segment of the trunk 
with five pairs of dorsal setæ, two of which between the tactile 
setæ. The sternum of the anal segment has at least two pairs 
and generally three pairs of setæ. 
Remarks. Of this genus no less than twenty one species are 
described in this paper. The species differ widely from each other 
in a very large number of features. It is possible to refer most of 
them to three groups, with P. Huxleyi, P. danicus and P. vulgaris 
as the central species of each group, but soine aberrant species, 
P. arinatus, P. spinifer and P. Mortensenii , would remain, and for 
the reason mentioned above I have not subdivided the genus and 
established several new genera. 
The genus has in all probability an almost world-wide di¬ 
stribution. 
