Dr. Strahl on the Systematic Position of the Thalassinz. 391 
of the imner antenna are very unequal in length: the first joint ~ 
is the longest, and the second the shortest ; the first joint is as 
long as the second and third together, and the third twice as 
long as the second. This antenna bears two flagella, of which 
the shorter inner one is as long as the antennal peduncle, and 
thicker than the other, and terminates in a rounded and almost 
clublike form. The outer flagellum is longer, more slender and 
acute. 
The outer antenna possesses no scale. Gebia, Laomedia, and 
Calhadne therefore group themselves closely together. The 
flagellum is simple and of the length of the thorax. 
The total length of the animal is 7 lines; but unfortunately 
we have no information as to whether it was perfectly developed. 
The outer maxillipeds are foot-lke; the outer palpus has a 
peduncle which is not quite so long as the second joint of the 
maxilliped, and it terminates in a multiarticulate flagellum. 
The first pair of feet is cheliferous. The hand, which is thinly 
clothed with hairs all over, is laterally compressed, yet the upper 
margin is not sharp or keeled, but rounded ; the carpus is longer 
than the fingers, and the fingers are acute. The first pair of 
feet is the longest, measuring about two-thirds of the total length 
of the animal. The following feet are monodactyle, slender, 
thinner than the first pair; they become shorter the further 
back they are situated, but the fifth pair becomes again not only 
longer, but also subcheliform. 
The abdomen is at first slender, but becomes broader towards 
the middle, and then again diminishes somewhat in breadth. 
The abdominal feet of the first segment are simple, thin, and 
rudimentary ; those of the following segments bear two appen- 
dages, of which the outer is large, long, and ciliated all round, 
but bears no filiform process ; the inner one, on the contrary, is 
small, only a fourth or fifth of the size of the outer one, but also 
eiliated all round. 
The caudal fan consists of a broad, rounded, central piece, 
which is of the same length with the lateral appendages; the 
latter are broad ; and all are ciliated on the margins. 
With regard to the characters of the sternum and of the 
tubercle on the intercalare, the figures give us no information. 
The other affinities to the Thalassine, however, allow us to sup- 
pose that there are no differences in these parts. 
Even Latreille united the genera known to him of the families 
Astacine and Thalassine subsequently established by Milne- 
Edwards, and De Haan contributed evidence in support of this 
union from their organization. The numerous Asfaci which 
were afterwards made known induced Erichson to separate three 
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