Report on the Crustacea Schizopoda of Ireland. 231 
only recognisable from one of the inner uropods, which has the inner margin 
finely serrulated throughout. This character appears to be confined to /. serrata. 
In other respects the uropod conforms equally to this species. 
Previous Irish Records.—Off Valentia, 80 to 100 fathoms (A. M. N.*): Mr. A. 
O. Walker has recorded the species from Station 115, having no doubt received 
specimens accidentally mixed with Amphipods, ete., from the same haul. 
Distribution.—Shetland; Moray Firth; Firth of Forth (A. M. N.*): Loch 
Ebyanveom (liao) saelci sli seam Amn Oey): 
Norway, 30 to 200 fathoms (G. O. S.): Denmark (A. M. N.*). 
It would appear, from the examination of Irish specimens, that existing 
descriptions of this species require modification. We find that the serrulation of 
the inner uropod, a character hitherto held to be of unreservedly specific value, is 
by no means constant; but is, in fact, practically confined to females and imma- 
ture males. 
In females, of which thirty were examined, the serrulation was invariably 
well-marked. 
In the male it appears to be lost with maturity, as testified by the perfection 
of the pleopods, and particularly by the full development of the setee of the copu- 
latory process of the antennule. 
Thus, of fifty-six males, twenty-four are devoid of serrulation on the inner 
uropods, and twenty of these, in which the antennules remain uninjured, have the 
setee fully developed. 
The remaining thirty-two males have the inner uropod serrulated; in twenty- 
five the setze of the antennule are undeveloped ; in two the sete are minute; in 
one the setze are about half-grown. In the remaining four the antennules are not 
available. A length of 10 mm., from the tip of the antennal scale to the 
extremity of the uropod, approximately represents, for our specimens, the greatest 
length of males with serrulated uropods. 
We considered it possible that the above remarks might be of purely local 
application, the absence of serrulation being a racial, rather than a specific, 
character. Sars’ figures (Monogr. over Mysider, Tab. 11.) could not be taken 
as evidence, since it was not certain that the serrulated uropod of his figure 11 
was taken from the same individual of which the anterior parts, with fully developed 
setee, are shown in his figure 10. However, we have since found in the Museum 
some specimens of L. serrata from the Asbjornsen collection, which appear to have 
been named by Professor Sars himself. One of them is a mature male, and its 
inner uropods are as innocent of serrulation as in the case of examples from the 
West of Ireland. The Asbjornsen specimens are from Lofoten. (See Note, p. 250.) 
It is possible that these facts are quite familiar to Professor Sars, but if he has 
published any modification of his original diagnosis, it has escaped our notice. 
2K 2 
