208 



NATURAL HISTORY. 



Fig. 27. COMMON BROWN SHRIMP (Crmitjon vulgarit). 



of sight is peculiar to the whole class. Even in those exceptional cases in which the eyes are 

 aborted, we find that in the earlier and larval stages of their existence the parasitic and sedentary 

 forms possessed eyes, and it is only as the effect of a kind of retrograde metamorphosis which the 

 animal undergoes that the organs of vision disappear in the adult. 



" The Brown Shrimp " (Crangon vulyaris) seems peculiarly an estuarine form, being taken in 

 large quantities in Morecambe Bay, Lancashire, the Lynn Wash on the Lincolnshire coast, the Thames 

 from Gravesend to the sea, and in the estuary of the Seine, especially near Honfleur. It is of a 



drab colour, dotted over with brown spots, and it 

 does not become red by boiling as most other 

 Crustaceans do. Its greatest length is two inches 

 and a half (Fig. 27). 



The absence of the prominent serrated beak 

 or rostrum, so marked a character in all the 

 Paloemonidce (Prawns and Shrimps proper), at once 

 enables the collector to separate the Crangonidse 

 therefrom. The chela3 of the fore hand are 

 present in Pakemon but absent in Crangon, in 

 which the fixed thumb is rudimentary. 

 !-<, An interesting little shrimp-like Crustacean, 



named' Alpheus, which occurs only rarely off the English coast, but is abundant on the shores of 

 Guernsey, Herm, and other of the Channel" Islands, and one species in particular of which, the 

 Alpheus ruber, is of a bright pink or salmon colour, has one claw of the first pair much more largely 

 developed than the other, whilst the second pair ai - e weak, slender, and many-jointed. This 

 character in the second pair of legs is also observable in the genus Nika, closely allied to Alplieus. 



All the members of this family (A Ipheadoe) are remarkable for the loud clicking noise which 

 they habitually emit. It does not seem certain whether this sound, which is always accompanied by 

 a sudden opening of the great claw to the fullest extent, is produced by impact of the heavy movable 

 joint of the chela against the fixed ramus or by the forcible withdrawal of the huge stopper-like tooth 

 from its pit in the penultimate joint of the claw. (Wood-Mason.) Col. Stuart Wortley remarks, 

 " Keeping them as I do in an 

 aquarium, it is startling some- 

 times in the evening to hear the 

 loud snap produced by sharply 

 striking together the two claws 

 on the larger leg." 



Palcemon serratus, the Com- 

 mon Prawn (Fig. 28), which is 

 so well known as a favourite and 

 delicate article of food, is found 

 in vast numbers on the south 

 coast of England. It appears 

 from various accounts that it 

 approaches the shore in its 

 young state, and multitudes 

 of them are taken in shrimp- 

 nets and sold as Shrimps. At 



Bognor the fishermen consider them, when young, as a distinct species, and assert that, at certain 

 seasons, they drive the true Prawns from their ordinary place of resort. The probability is 

 that, at the season when the young ones have arrived at a certain size, they separate 

 themselves from the older ones, which at that period of the year retire farther from the shore. 

 At Poole the young ones of this species were commonly found associated with two other 

 species of Palcemon, and the three are ordinarily sold there under the name of " Cup Shrimps," being 

 measured in small cups instead of being sold by tale, as they are when larger. When of middle size 



Fig. 28. COMMON PRAWN (Palaimon serratus). 



