HERPYLLOBIUS ARCTICUS. 
401 
{go.) lie side by side at the base of the drawn-out anterior end^ 
and near its apes there appears to be another opening [m.) 
which is not so obvious as the genital apertures, but its 
position is indicated by a strand of tissue running up to it. 
This is the “mouth” described by Jensen, and he further 
finds a pair of mandibles and two pairs of small processes, 
])Ossibly rudiments of appendages, on the hinder pair of 
which there open a pair of glands which secrete cement for 
fixing the male to the female. My specimens, however, 
showed no mandibles or processes, and their existence is 
denied by Hansen (5), who furthermore declares that there is 
no mouth opening at all; I am, however, inclined to believe 
that a mouth is present, although it is degenerate and 
probably functionless. 
The body part of most of the males is chiefly occupied by 
two large spermatophores {sp.) oblong, in shape and provided 
with long necks {sp. d.), which emerge through the genital 
opening; these are evidently for insertion into the female 
and may be of great length ; in one of my specimens they are 
twice as long as the whole animal. A similar structure has 
been described by Hansen in the allied genus Rhizorhina.^ 
Jensen believes that the cement for the spermatophores is 
derived from two large glands occupying all the ventral and 
part of the dorsal surface anterior to the single testis (6, 
tal). ii) ; none of my specimens, however, sliowed this gland ; 
and Hansen considers that the cement is derived from the 
vas deferens. 'I'he spermatophores, according to Jensen, are 
shed from the body of the male, and he figures them 
(6, fig. 11a) attached to the female close to the genital 
openings; they were not to be found on any of my 
specimens. 
The anterior position of the genital openings of the male 
is an unusual occurrence among Crustacea, and Hansen (4) 
questions whether it can be said to occur in this case. He 
describes the male larvae as attaching themselves to the 
female at an early stage, and subsequently undergoing a 
' Loc. cit., tab. iii. 
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