288 MARINE INVERTEBRATES 
ORDER STOMATOPODA 
Genus Squilla 
S.empusa. This animal suggests somewhat the lobster, though very 
unlike it. The carapace is much smaller and softer, and leaves the last 
three segments of the thorax uncovered. The abdomen is larger and 
longer in proportion, while the legs 
and organs are quite different. 
The whole body is depressed, in- 
stead of laterally compressed. It 
/, measures from eight to ten inches 
\ My in length andtwo inchesin breadth. 
Y vy Instead of chele, the last joint of the 
great claw has six sharp curved 
spines, which fit into sockets in a 
groove on the second joint. By 
this singular organ they hold their 
prey securely. The abdominal 
feet carry the gills. The antennal 
scales are oblong and fringed with 
hair. The antennules terminate 
in three flagella. The caudal ap- 
pendages and telson are long, 
strong, and armed with spines. 
This animal lives in burrows in 
the mud below low-water mark, 
forming large, irregular holes, but 
is frequently washed ashore. In 
color it is pale yellowish-green, 
each segment being bordered with 
darker green and edged with 
yellow. It is found from Cape 
Cod to Florida. 
ORDER CUMACEA 
Genus Diastylis 
D. quadrispinosus. Among 
the minute Crustacea which swim 
on the surface of the water, this 
species, with other small forms, 
may be captured by using a muslin 
net. It is a quarter of an inch 
or less in length. It is easily 
Squilla empusa, the mantis-shrimp. distinguished by its large carapace, 
: the posterior portion of which is 
marked off in transverse ridges, the anterior end running into a sharp- 
pointed rostrum. It has a long, slender abdomen, the sections of which 
