4 T. V. HODGSON. 
to any other members of the genus. The two species, as species are recognised 
now-a-days, are perfectly distinct, but it is a fair question to ask how is their 
present position at the opposite ends of the earth to be accounted for ? 
As to the terms employed in the following work, some words of explanation 
are necessary. 
Naturalists have not always used the same terminology, and Mr. L. J. Cole (6) 
has recently tabulated the essential variations. As, however, the terms used by 
any one naturalist have not been fully adopted, and others have been introduced, 
a complete account of the terminology used here is given. 
The entire Body of a Pycnogonid is divisible into three regions—the proboscis, 
trunk, and abdomen—and this without regard to any of the appendages. Where 
the body only is alluded to, it is to be understood that both the trunk and abdomen 
are taken together. Measurements are taken dorsally, unless otherwise specified, 
except in the case of the appendages, which are generally measured from the side, 
and the length of the trunk is usually taken to the base of the abdomen ; in exceptional 
cases, where the abdomen is vertical or very short, the trunk may be measured to 
the extremity of the posterior lateral processes, but this is so stated. Its width 
is always across the longest of the lateral processes. 
The Cephalon is regarded as that portion of the trunk which lies in front of 
the first pair of lateral processes, and the so-called neck is the narrowest part, 
sometimes elongated, between those processes and the more expanded distal portion. 
Segmentation is not regarded as perfect or complete unless the four segments 
of the trunk and the abdomen are distinctly articulated. 
The first appendage of the trunk is the Cheliforus, also commonly known as 
the mandible. A considerable amount of confusion has been, and is still likely to 
be, caused by the fact that the chela has most frequently been regarded as a single 
joint. Obviously it consists morphologically of two joints, and in order to avoid any 
misapprehension as to the number of joints, this appendage has been described as 
chelate, or otherwise, and the scape, a name given by Professor G. O. Sars to the shaft 
supporting the chela, has been recorded as one- or two-jointed, as the case might be. 
This method of dealing with the limb is suggested in order to avoid confusion as 
to the number of joints it possesses. 
The second appendage is the Palp. 
The third appendage is the Oviger. This convenient name was given by 
ce 
Mr. L. J. Cole to replace the more cumbrous term “ ovigerous,” or “ false leg.” = In 
these two appendages the various joints are numbered from the base, and not named. 
5 : ’ 
The remaining four or five pairs of appendages are Legs pure and simple; with 
‘ 
the use of the word ‘oviger,”’ the qualification “ambulatory” or “ walking leg” 
s 1 g les 
becomes quite unnecessary. The terms used for the individual joints are those 
adopted by Professor G. O. Sars, viz., first, second and third coxa, femur, first and 
second tibia, tarsus and propodus. 
