Parapherusa crassipes (J/asvvel/). 205 
margin and protrudes considerably, so that the propod is 
then broadest at the base instead of being narrowest at the 
base as in the female and young male. Practically all the 
transition-stages between these two extremes can be found. 
The second gnathopod in the female (fig. 14) has the same 
general shape as the first gnathopod, but is larger, and differs 
in having the carpus shorter and triangular, being only about 
half as long as the propod; the propod is oval, widest about 
the middle, narrowing a little towards the distal end. ‘The 
arrangement of sete on all the joints is practically the same 
as that on the first gnathopod, and can be readily understood 
from the figure without further description. 
In the male the second gnathopod (Pl. X. fig. 15) is very 
large and strong, the basal joint is rather short and is broad ; 
on the outer side the margin forms a thin flange and is produced 
at the distal end into a small rounded lobe, so that a groove 
is formed on the anterior surface of the basal joint, into 
which the distal portion of the limb fits when reflexed ; the 
ischium is short and has its outer margin also produced into 
a small lobe; the merus is short and produced at its antero- 
distal angle into a subacute point; the carpus is short, tri- 
angular, and cup-shaped, being hollowed at the end to receive 
the greatly enlarged propod; the propod is oblong-oval, 
widening slightly distally ; the palm is slightly oblique, well 
defined by a sharp tooth, and has a large flat-topped tooth 
near the base of the finger and a wide lobe at the centre of 
the palm, with a deep rounded depression at each side ; the 
finger is particularly large and strong. 
In the fully developed second gnathopod of the male the 
setee are very few, sometimes there are two or three small 
tufts along the hind margin of the propod and a very small 
tuft at the distal end of the anterior margin at the base of the 
finger, and a few very short setze on the palm. In still older 
specimens even these few sete are hardly distinguishable, 
while, on the other hand, in younger males the sete may be 
longer and more abundant and are present on the anterior 
margin as well as on the hind margin, so that the whole 
appendage approaches more nearly to the form found in the 
female. 
The first and second pereopods (fig. 16) are moderately 
broad, especially the basal joint; the side-plates are rectangular 
in both. There are no signs of glands in any of the joints 
similar to those in Jassa, the Corophiide, ete., and these 
erecopoda do not call for detailed description. 
The third, fourth, and /fi/th perwopeds (fig. 17) are all 
stout, particularly the fourth and fifth ; they increase some- 
