Lincolnshire Crustacea. 301 
POTAMOBIUS PALLIPES, Leveboudlet. Tue River CRAYFISH. 
Is an interesting species, being the only large crustacean that 
inhabits fresh water. The specimens illustrated were sent to 
the County Museum by Mr. H. Preston, F.G.S., taken from 
Cringle Brook, a tributary of the Witham at Great Ponton, 
where they are commonly found under stones. 
It is perhaps better known as Astacus fluviatilis, but by this name 
is confused with another European species. 
NEPHROPS NORVEGICUS, Leach. Norway LossTeEr. 
Is sparingly distributed on our shores, though said to be numerous 
on the Irish Coast, and is very common on the Norwegian coast, 
and is brought into our fish markets and sold as ‘“‘ Norwegian 
Prawns ’”’ in large quantities. 
The specimen figured was caught off the Lincolnshire coast and 
brought alive to the writer by a longshore fisherman. It is one 
of the very few specimens that can be said certainly to have 
occurred on the Lincolnshire coast. 
PURTUNUS DEPURATOR, Leach. SWIMMING CRAB. 
Taken by the writer whilst dredging at the mouth of the Humber. 
Sometimes they may be found washed ashore by a rough sea, 
and found sparingly among the debris deposited at high water 
mark. 
PORTUNUS PUSILLUS, Leach. DwarF SWIMMING CRAB, 
One damaged specimen dredged off Boston, October, 1906, by Mr. 
H. Donnison. 
CORYSTES CASSIVELAUNUS, Leach. MASKED CRAB. 
The two upper specimens were taken whilst dredging at the mouth 
of the Humber, by the writer. 
The lower one was dredged off Boston by Mr. H. Donnison, and 
sent to the County Museum, October, 1906. 
All the specimens are males. The anterior legs of the female are 
much shorter. 
HYAS ARANEUS, Linn. SPIDER CRAB. 
This is a commor species along the East Coast, and when in its 
element has a most untidy appearance, generally being covered 
with zoophytes, and a host of marine objects. The specimens 
figured were dredged off Boston and presented by Mr. Donnison, 
October, 1906. 
