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 



