THE STALK-EYED CRUSTACEA. 255 



species, Thia polita, curiously enough, does not belong to this 

 group, but is a true crab. 



The vShrimps (Crangonidae) and Prawns (Palaemonidae) are 

 most interesting animals and are well represented on the Essex 

 coast. The true Shrimp, Crangon vulgaris, may be at once 

 recognised by the flat cephalo-thorax and its sand-like colour. 

 It is the " Brown Shrimp " because it does not turn red on being 

 boiled like the prawn under like treatment. 



[Mr. Lovett made the following observations in the Zoologist 

 for 1885, pp. 468 — 9, which we have often verified when noticing 

 shrimps in the sea-rivulets on our Essex coast : — "The colour of 

 this species is grey or brownish-grey, speckled with darker cells 

 of pigment, but, of course, like many crustaceans, this colour 

 varies according to the habit of the specimens ; for those from a 

 light sandy bottom are paler and slightly yellow, whereas those 

 from a muddy estuarine locality are dark and dirty looking : in 

 fact, so completely does Crangon vulgaris resemble in tint the 

 bottom On which it lives, that it is absolutely impossible to detect 

 it when motionless. I have frequently observed this in shallow 

 clear water where shrimps almost covered the sand ; and yet, 

 when not actually moving, not an outline could be traced or 

 a single living thing seen, but on alarm hundreds of little 

 flashes showed where these thoroughly invisible tiny things 

 really were."] 



Several other species of the genus Crangon occur on the 

 Devon and Dorset coasts, but are rather rare. Alphens ruber, a 

 rare and brilliantly coloured species is found at Herm in the 

 Channel Islands. This animal possesses the power of making a 

 sharp clicking sound by means of a spine at the base of the first 

 abdominal segment ; much in the same fashion as that of the 

 "skip-jack " beetle. AtJianas niicscens is another somewhat rare 

 species from Jersey, as also is Hippolyte spinus. 



Pandalus annulicornis is really a "prawn" and is a topical 

 Essex form. It is in fact the " Fved 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 South- 

 hampton I saw Palcemon squilla (the small prawn) hawked about 

 under this commercial name, and P. varians, where it occurs 

 commonly, is also so called. 



