64 Alf Wollebæk. [No. 12 
but differ in being united by a distinet *bridge” a little in front 
of their middle. I have dissected a considerable number of speci- 
mens and in every case found this bridge existing. On the other 
hand EnrenBavm in the case of Crangon vulgaris has sometimes 
found å bridge present and sometimes not. According to GROBBEN 
(, Beitråge zur Kenntniss der månnlichen Geschlechtsorgane der 
Decapoden*, Arbeiten aus dem Zoolog. Inst. Wien, 1 Heft 1878). 
a bridge of this nature is nearly always present in Decapods be- 
tween the right and left testes, and very often there are even two. 
It is only in very exceptional cases, as for instance in Pagurus, 
that the bridge is absent. 
Vas deferens is in the main the same as in the two pre- 
ceding species. It has an even simpler coil than that of P. borealis. 
In younger specimens the coil was smaller (Pl. XII, uppermost 
figure on left). 
Qvaries are connected by å bridge and are for the most part 
united at their posterior ends. 'The anterior ends are free, and 
partly more or less diverging partly lying closely side by side. 
Secondary sexual characteristics: On examining the 
ist and 2nd pairs of pleopods of a considerable number of speci- 
mens of different sizes I found in the females the usual elongated 
tip on the inner branch of the 1st pair of pleopods (fig. 5 ID). 
In ovigerous females the tip of the inner branch was posteriorly 
bent back round the ova and the setose covering on the inner 
branch was far more highly developed than in non-berried indivi- 
duals. These seem to be the usual conditions. MorTENSEN?*) men- 
tions the same thing in Palaemon Fabric" and Firen»savm*) in 
the case of Crangom vulgaris. In quite young females the inner 
branch is of an oval shape and is not drawn out to a tip. [Com- 
pare fig. 3, page 59 of åa Pandalus borealis 47 mm. long. Å similar 
shape was found in å P. annulicormis 27 mm. long]. 
In males I found two different shapes. In some cases the 
organ of copulation of the inner branch was straight and strong as 
in fig. 5 I, while in other specimens there was å weak, often 
1) Ta. Mortensen: Undersøgelser over vor almindelige Rejes (Palaemon 
Fabricvi RI.) Biologi og udviklingshistorie etc. Kjøbenhavn 1897. 
2) Dr. E. Enrrenpaum: Zur Naturgeschichte von Crangon vulgaris FABR., 
etc. Berlin 1890. 
