Dr. Strahl on new Thalassine from the Philippines. 385 
distinction, sometimes for this piece, sometimes for the first 
joint of the antenna, and sometimes for parts anchylosed to the 
latter. For this reason I thought it better not to employ this 
otherwise suitable word. The structures referable to the scale, 
or the external branch, according to Kréyer’s terminology, con- 
sist, according to him, in the embryo Lobster, of two joints, of 
which that placed nearest to the body is, in my opinion, the 
armiger, whilst the extreme one becomes the scale. At a sub- 
sequent period the armiger must approach nearer to the antenna 
and receive the articulation of the first two antennal joints. In 
the mature Lobster, at Icast, the armiger is not a complete ring, 
but is obliquely cut off on the inside, and open there for the 
purpose of receiving the articulation of the first two antennal 
joints; the articulation with the intercalare lies in a direction 
from above downwards, that is, from the dorsal surface towards 
the ventral surface; the upper articulation is effected upon the 
carapace, the lower or ventral one on the anterior margin of the 
intercalare. The articulating axes of the intercalare and armiger 
therefore cut each other at a right angle, whilst the articulating 
axis of the scale lies in the same direction as that of the armiger. 
The first antennal joint is, then, articulated partly on the inter- 
calare and partly on the armiger. The articulating axis in ques- 
tion is directed from within outwards, and therefore at a right 
angle to the axis of the articulation between the intercalare and 
armiger, but in an oblique direction from behind forwards, in 
such a manner that the inner and posterior condyle articulates 
with the intercalare, and the outer and anterior one at a con- 
siderable distance forwards upon the ventral face of the armiger, 
near the articulation of the scale. The second antennal joint 
is articulated both to the first joint and to the armiger; the 
articulating axis is directed from within outwards; the inner 
condyle is articulated to the anterior inner angle of the first 
joint, the outer one to the ventral anterior margin of the armiger, 
where it is received by a pit, which is situated quite close to the 
ventral articulation of the scale. This inner condyle is often so 
peculiarly marked, forming as it were a particular dilatation 
of the second antennal joint, that it frequently appears to be a 
separate articulated portion of the skeleton. One is led to this 
erroneous supposition especially when a true scale is wanting ; 
this piece is then easily mistaken for an aborted scale, This is 
the case in Callianassa (with Leach’s C. subterranea and the 
species here described), in Thalassina scorpionotdes, and in Bell’s 
genus Calocaris. In the latter the armiger bears externally an 
acute spine, whilst in the two Callianasse and in the Thalassine 
it is unarmed. 
The scale-apparatus in the Thalassine may therefore be so far 
