Dr. Strahl on the Systematic Position of the Thalassine. 393 
must put off more detailed statements for the present, and will 
only mention here that even these phenomena of growth are 
greatly in favour of the Phyllosomata being the young state of 
some Podophthalmatous Crustacean. In all the above-mentioned 
Phyllosomata, and in the other specimens contained in the Berlin 
collection, I have succeeded in confirming Kréyer’s observation 
as to the presence and position of the auditory vesicle. What 
Gegenbaur and Lenckart have sought in vain in fresh examples 
may be easily seen in spirit-specimens: the coagulation effected 
by the alcohol probably facilitates the detection of contours 
which, under other circumstances, are too delicate. Moreover, 
the Phyllosomata already possess the tuberculum ; at least, this 
was what I considered to be the nature of a tubercle, situated close 
to the outer antenna. The outer antenna here is destitute of 
any indication of an antennal scale; and this would also be in 
favour of its belonging to Palinurus. I could not make out that 
the elevation considered by me as the tuberculum was situated on 
a separately articulated piece; and it would likewise constitute an 
agreement with the Palinuri that the tubercle was placed in front 
of the mouth upon the anterior segment, which is undivided 
and bears the eyes and the two antenne*. 
The position of the auditory vesicles is surprising: they are 
situated within the brain, and occur elsewhere in the first joint 
of the inner antenne. During further growth, the auditory 
vesicles must push forward, and, changing their form, get into 
the first joint of the inner antennz, and open themselves; whilst, 
on the contrary, the ¢ubercula move nearer to the mouth and 
more towards the median line. But this must be cleared up by 
further observations. 
In the vicinity of the elevation regarded by me as the tuber- 
culum, and not far behind it, there is, in the interior, in front of 
the fan-like liver, a peculiar mass, the external contours of which, 
resembling convolutions of tubes, lead to the conclusion that it 
is a glandular organ. To this mass some filaments run from the 
brain; it is paler in front, darker behind. ‘This is probably 
Suckow’s gland, which always consists of two differently tinted 
portions. 
From the above it appears distinctly that the Scyllaride and 
Palinuride are not more nearly allied to the Thalassine and As- 
tacine than to the Palemones, Penei, &c. We have now to 
ascertain wherein consists the near affinity of the Astacine and 
Thalassine. In the first place, the scale of the external antenne, 
which is wanting in some genera, rudimentary in others, and in 
others, again, more highly developed, but never attaining to the 
* Perhaps the Phyllosomata of which Milne-Edwards says that their 
antennz are “ Jamelleuses’’ may belong to some Scyllaride. 
