1908] - Decapod CUrustaceans. 43 
contrary the inner lash is the thicker and stronger, and it is densely 
setiferous right to the tip (in the males the corresponding lash is 
only densely setiferous in the proximal half): the outer lash of the 
female is much thinner, though shorter, than the inner one, as was 
also the case with the male: but there is less dissimilarity between 
the relative lengths of the two lashes in the case of the female. 
M. Sars in the work referred to mentions also, both in the 
ease of Pontophilus norvegicus, P. spinosus and Cheraphilus echinu- 
latus the characteristic sexual differences to be found on the 2nd 
pair of pleopods. In the males we find two small appendices 
(appendiz interna and appendix masculina) on the inner branceh, 
while in the case of females there is only one (appendix interna). 
Appendices mternae which are found also in both sexes on the 3rd, 
4th and 5th pairs of pleopods have their tips furnished with small 
hooks *eineinnuli”. [See Pandalus borealis page 60, where they will 
be found depicted and fully described for that species. There is å 
close resemblance between those of Pandalus and several others 
and those of Pontophilusj. "These appendices mternae probably act 
as organs of attachment. M. Sars is of opinion that the same is 
also the case with appendix masculima, at any rate as far as Uhera- 
philus echimulatus is concerned. In this species a. masculima is 
furnished with 20—30 fairly stout long spines, which along one 
side are serrated, with uneiform tips, and *seems unquestionably to 
act as an organ for holding fast the female during the pairing time.” 
Other authors have described a. maseulind as "the organ of copu- 
lation.” 
In the JMacrurae variously shaped organs of attachment, in 
which capacity a. interna seems in any case to act, are commonly 
found on the pleopods. In some cases they are found in both sexes, 
in others they are only present in the males. According to GER- 
STAECKER and ORTMANN (Klassen und Ordnungen der Arthropoden, 
1901 pages 897—898) it is generally the pedunele of the pleopod 
itself which is furnished with an organ of attachment. After men- 
tioning organs of this nature for Sergestes, Penaeus and Sicyonia 
he states (page 898):— 
*Abweichend von den vorgenannten Gattungen ist es in an- 
deren Fållen nicht das Stammglied sondern der innere Spaltast, 
welcher mit besonderen Haftapparaten versehen ist. Auf eine ein- 
fachere Form solcher hat M. Sars (1868) fir verschiedene, von ihm 
nåher untersuchte Cramgon-Arten, z. B., Urangom (Pontophilus) 
