KEMP—PELAGIC CRUSTACEA DECAPODA 57 
Three specimens, in which the outer uropod is externally ciliated throughout its 
length, appear to belong to this widely distributed species. 
I have devoted considerable time to the remainder of the Sergestes in the collection, 
but have been unable to satisfy myself of their identity. The specimens are not numerous, 
and are, for the most part, in poor condition. Some appear to belong to the group 
comprising S. halia, Faxon, and S. incertus, Hansen, while one male, 38 mm. in length, 
seems to represent a new species allied to the Atlantic S. hensent, Ortmann. This specimen 
is of considerable interest, but its damaged condition precludes a complete statement of its 
specific characters. It agrees with S. henseni in the possession of two pleurobranchs at the 
base of the third perzeopods, but differs in the absence of a supra-orbital spine and in the 
armature and larger number of subsegments (apparently seven) in the terminal segment of 
the third maxillipedes. 
Lucrrer, Vaughan Thomson. 
The members of this genus are very imperfectly known and, owing to the incomplete 
accounts which most of the earlier authors have given, the synonymy of the various species 
is very difficult to trace. 
Vaughan Thompson*, when first describing the genus, omitted to give a specific 
name to the form which he examined ; the figure probably represents ZL. acestra of Dana 
(=L. reynaudiu of most recent authors) but of this there is no certainty. 
I agree with Faxon that Milne Edwards’{ figure of L. reynaudi and his descriptions 
of that species and of L. typus are quite insufficient for exact identification ; the account 
given by Eydoux and Souleyet§, who regard these two forms as sexes of a single species, 
is equally unsatisfying and it is only with the publication of Dana’s work in 1852|| that 
a sound basis for the classification of the species is reached. Dana's treatment is fortu- 
nately very good and surpasses that of nearly all subsequent writers; the identification 
of all the forms which he has described should not be a matter of any considerable 
difficulty. 
The use of the nomenclature which Dana proposed has, however, one serious draw- 
back: the name LZ. reynaudii must be employed in a different sense from that adopted by 
most recent writers. The species which he recognised as that originally described under 
this name by Milne Edwards—a species which must henceforth bear the name L. reynaudi, 
M. Edw. (Dana)—is unquestionably distinct from the long-eyed form to which most 
authors have assigned the name. The latter form, as Faxon has pointed out, is L. acestra, 
Dana. 
Dana did not refer any of the species he examined to JL. typus, M. Edw.; his 
L. pacificus, according to Ortmann, is to be regarded as a synonym of that form, but no 
* Vaughan Thompson, Zoological Researches, Cork, 1829?, Mem. iii, p. 58, pl. 7, fig. 2. 
7 Faxon, Mem. Mus. Comp. Zool. Harvard, xviii. 1895, p. 214. 
{ H. Milne Edwards, Hist. Nat. Crust. ii. 1837, p. 469, pl. 26, fig. 10. 
§ Eydoux and Souleyet, Voy. de la “Bonite,” Zool. i. 1841, p. 249. 
|| Dana, U.S. Explor. Exped. Crust. i. 1852, p. 668. 
{| Ortmann, Zool. Jahrb. Syst. v. 1890, p. 454. 
SECOND SERIES—ZOOLOGY, VOL. XVI. 8 

