THE SHORE CRAB, 75D 
external maxillipedes. Antero-lateral margin of the cara- 
pace with three teeth. 
Herograpsus sexdentatus.—Legs smooth. 
Heterograpsus crenulatus.—Legs with long hairs. 
Genus Cyclograpsus.—Internal antennz concealed by the 
front. Antero-lateral margins of the carapace entire. 
Cyclograpsus lavauxi.—Carapace and legs nearly smooth 
with marbled spots. 
Genus Helice.— Internal antennz concealed by the front, 
Antero-lateral margin of the carapace with two teeth. 
Felice crassa.—¥ront half as long as the width of the 
carapace. Hands short and high. 
GENUS Plagusia.—Internal antennz exposed in a longitudinal 
sinus of the front. Hands longitudinally ribbed. 
Plagusia chabrus—Front terminated anteriorly by a 
granulous border, curved, and armed above with 
two acute spines. 
3. Internal structure.—Fasten the animal to the loaded 
cork by pins through the legs. Cut with a knife the 
attachment of the abdomen with the carapace, taking 
care not to cut deep. Insert the point of the scissors 
into the opening into the branchial cavity on one 
side of the abdomen, and cut the carapace just 
inside the margin up to the orbit. Do the same 
with the other side. Slightly raise the posterior 
portion of the carapace, and with the handle of a 
knife detach it from the soft parts of the animal. 
With the scissors cut the carapace close along the 
front, and remove it. 
4. Cover with water. A dark black or blue-black skin 
will be found covering the viscera. Carefully 
remove this. Observe the angular heart, lying in the 
pericardium, in the median line, just in front of the 
abdomen. In front of the heart the large stomach, 
containing some hard calcareous pieces. On either 
