38 
Notes on a Variety of Portunus marmoreus. 
By Epwarp Strep, F.L.S. Read May 27th, 1897. 
HEARING that the ground seans were being worked on Pendowa 
Beach one evening at the end of March, I wandered up in the hope of 
finding a few specimens of no value to the fishermen. _ It was quite dark 
when I arrived, but had it been a night too dark to see anything I 
should have found the exact locality of operations, owing to the barking 
of four or five dogs that were keenly interested in the affair, and getting 
under everybody’s feet. It was the right moment, for the men were 
just hauling in the long net and picking out the meshed mackerel and 
“flats.” I saw the fish all cleared out and shared, the sean care- 
fully heaped on the sand-dune far above high water, and the fisher- 
men depart to their homes. Then came my turn. I wanted some 
specimens of Corystes casstvelaunus, the long-armed or masked 
crab, and should have brought a lantern with me to aid in the 
search. A few matches were all Ihad in the way ofalight. Seeking 
the “cod” or bag of the sean, and striking a match, I saw several 
large shore-crabs (Carcinus mcanas) and velvet fiddlers (Portunus 
puber), all active and noisy, and thena fine male of Corvyszes. Several 
other specimens of Coryszes were obtained, but having exhausted 
my matches, it was easier to get a painful nip from the savage 
fiddlers than to find the more friendly long-arms. Having previously 
learned that two other seans had been hauled higher up the bay, 
I determined to defer further collecting until the following day. 
A more careful examination of the three seans next day yielded 
not only a number of specimens of Coryszes, but also several of 
Polybius henslowit, Leach, and Fortunws marmoreus, Leach, both 
desirable finds, for I had not previously obtained good specimens of 
either, they being pelagic in habit. Polydzus is the swimming crab par 
excellence, for all its limbs with the exception of the powerful chele 
are flattened for swimming, and the terminal joints of the fifth pair 
are admirable swimming plates halfan inch across, and three quarters 
of an inch long, looking as though they had been hammered out thinly 
to make the most of the material. Then the entire shelly matter is 
everywhere exceedingly thin and light, to suit its habit of mounting 
to the surface waters, and chasing such active fishes as the mackerel, 
to whose back it clings, and from which it carves its dinner. 
But I am getting away from my subject, which is Portunus mar- 
moreus. Judging from the specific diagnosis given by Bell, he is 
right in the supposition that P. marmoreus and P. holsatus are 
forms of one species; and not greatly differing forms, for without 
reference types it appears to me that the chief distinction between 
the two is the comparative breadth and length of the terminal 
joints of the last pair of limbs. According to this slight foundation 
upon which to build a new species, my specimens are all referable 
