60 Papers from the Department of Marine Biology. 
This tip is not attenuated, as in most crabs, but is comparatively 
broad and rounded and bears several small sete. The posterior 
appendage is much shorter and is inserted in the basal cavity of the 
anterior appendage. Its apex is broad, not stylet-like, as, for instance, 
in Cancer. The generally accepted function is that of forcing the 
spermatozoa into the spermatheca of the female by working up and 
down in the cavity of the anterior appendage when the copulatory 
organ is introduced into the vulva of 
the female, and its piston-like structure 
would indicate this here. 
I have not observed genital papille. 
The great length of life in Arthropod 
spermatozoa is of course well known. 
The case most often quoted is the bee, 
where the queen is only once fertilised. 
In the other Brachyura it is said that 
the spermatozoa “remain inside the sper- 
matheca for many months before they 
fertilise the ova.”’ (I quote from Pear- 
son.) 
THE EGGS AND LARVZ. 
The eggs of Hapalocarcinus are quite 
large in size and heavily yolked. I never 
observed the larve hatching, but a great 
many of the individuals collected bore 
larvee very nearly ready to be set free. 
They are then in the zoza stage, with 
ante Fig. 15.—Zowa larva of Hapalocar- 
very distinct frontal, dorsal, and lateral cinus. X90. 
spines, and large paired eyes in the head. 4-s.,/.s.,f.8., dorsal, lateral, and frontal 
spines. 
All the head appendages are developed ,,. grst and second antennz. 
and the first two maxillipeds, large bi-  mz., first and second maxille. 
ramous structures, in the thorax. The ™?” St aed Speed aeons 
segments of the abdomen are quite distinct and there is a forked 
telson. It seems, then, that this stage corresponds to the first zozwa 
stage of Cancer (Pearson) and thus hatching takes place here at a 
slightly later stage. The great difference between the protozoa (the 
hatching stage in Cancer) and the first zowa is the presence of the 
frontal and dorsal spines. The protozoza is apparently omitted from 
the life-history of Hapalocarcinus. 
The spines of the carapace are less prominent than in Cancer. The 
dorsal spine is longest. The first antenna is short and stumpy; the 
second antenna is very short but biramous. The mandible is visible 
as a not very definite plate. 
