CRUSTACEANS in Canada balsam or when kept in strong glycerine, such preparations being extremely satisfactory.' Of Porcellana longicornis (Linn.) he says : ' I have obtained most of my specimens in dredging just outside Harwich harbour where it lives amongst the sandy tubes built up by Sabellaria aheolata. A few have been collected off Mersea of somewhat larger size and having one claw much longer than the other.' In regard to the Macrura, Mr. Lovett states that ' the shrimps (Crangonidae) and prawns (Palaemonidas) . . . are well represented on the Essex coast.' Of the former group however he only specifies Crangon vu/garis, dignifying it by the title of 'the true shrimp,' and explaining why it is called ' the brown shrimp,' * because it does not turn red on being boiled like the prawn under like treatment.' He comments on the nice adaptation of its colouring to the sand or mud on which it is found by the lighter or darker speckling of its grey or brownish-grey coat, so that in shallow clear water, where shrimps almost cover the floor, they will remain unperceived till some sudden alarm startles them into motion, and then ' hundreds of little flashes ' show their passage from one station of invisibility to another. Mr. Cole speaks of having verified this observation in the sea-rivulets of the Essex coast, as many other seeing eyes will have done both there and elsewhere. That C. vu/garis, Fabricius, is the true shrimp may well be admitted as a patriotic opinion among Englishmen, though, if shrimps could express their views, the idea would no doubt be laughed to scorn by the far more magnificent Crangonidas of the arctic regions. On the companion group Mr. Lovett remarks : ' Pandalus annulicornis is really a " prawn " and is a typical Essex form. It is in fact the " red shrimp " of the Thames excursion steamers. It works the tide up and down for its food, and is a most useful scavenger. The term " red shrimp " is applied to several diverse species round the coast. At Southampton I saw Palcemon squilla (the small prawn) hawked about under this commercial name, and P. varians, where it occurs commonly, is also so called. 4 The true prawn (P. serratus) is also an Essex species and well known. P. squilla is a small form from the western part of the Channel, where it is " the prawn."
- P. variant is another and decidedly Essex form, occurring in vast
numbers in the creeks and inlets of this part of our coast.' ' On these records one or two comments may be offered. It is no more easy to determine what is ' really a prawn ' than what is ' the true shrimp,' for both appellations are essentially vague and defy definition. When narrowly applied, each of them still includes several genera and species. Size is no criterion, for while some shrimps are much larger than our common prawn, there are some prawns as large as good-sized lobsters, and others no larger than our common shrimp. If prawns be limited to the Palasmonidae, then Pandalus annulicornis is not really a prawn, 1 The Eiiex Natura/ist, vol. xi. pp. 255, 256 (1900). 207
