Reprinted from the Journal of the Marine Biological Association, 
N. S., Vol. w., No. 3, August, 1896, 
Contributions to Marine Bionomics. 
By 
Walter Garstang, M.A., 
Fellow and Lecturer of Lincoln College, Oxford. 
I. The Habits and Respiratory Mechanism of Corystes 
cassivelaunus. 
Corystes cassivelaunus is a crab of unusually narrow and elongated 
form, which has received the popular name of “ masked crab” from the 
grotesque resemblance which its sculptured carapace bears to a human 
face. It is common round all the coasts of the British Isles, and, 
although normally an inhabitant of the deeper water, is occasionally 
found at home in sandy pools on the sea shore, and is frequently cast 
up in hundreds on sandy shores after heavy gales. 
J. SysTEMATIC POSITION. 
The systematic position of the Corystoidea has long been a disputed 
point among carcinologists. Henri M. Edwards (1834) placed the 
Corystoid crabs near the Dorippide among the Oxystomata, and re- 
garded them as connecting links between the Cancroidea (vid the 
Calappide) on the one hand, and the Anomoura on the other. 
De Haan (1849) removed the family from the group Oxystomata 
altogether, and placed it with the Cyclometopa and Catometopa of 
M. Edwards, in a separate sub-division of the Brachyura, the Brachy- 
gnatha. 
Dana (1852) made of the Corystoidea an independent and primary 
tribe of the Brachyura, distinct from the Cancroidea and Leucosoidea 
alike. 
Alphonse Milne-Edwards (1860) reverted to the older view, and 
placed the Corystide near the Calappoid Oxystomata. Heller also 
_ (1863) placed the Corystidee among the Oxystomata. 
Finally, Claus (1880) definitely placed the Corystide in the Cyclo- 
metopa. In this he has been followed by Miers (1886) and Stebbing 
(1893). 
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