CRUSTACEANS 



The student of Crustacea will find in this county much more to 

 interest him than might be expected from the printed scientific records. 

 Those indeed which refer to this branch of its fauna are, with one ex- 

 ception, meagre in the extreme, not devoting to the subject more than 

 three or four brief and rather casual notices. In his ' Notes on the 

 River Rib from Standon to its Junction with the Lea,' Mr. A. G. Pullen, 

 F.Z.S., writes that, ' of crustaceans, the crayfish or crawfish, Astacus 

 flu'viatilis, is frequently met with at all parts of the Rib, and is especially 

 abundant near Letchford.' ' Mr. John Hopkinson, F.L.S., has kindly 

 found for me a notice of its occurrence in the river Gade, 8 and Mr. A. 

 E. Gibbs, F.L.S., after telling me that ' crayfish are to be found in the 

 river Lea in the neighbourhood of Wheathampstead,' very obligingly 

 went more minutely into the question of the distribution of the species 

 in that neighbourhood. The result of his further enquiries was as fol- 

 lows : ' I am told,' he says, ' that it is not to be found higher up than 

 (i.e. on the Luton side of) the Harpenden Great Northern Station, and 

 that it is found from there to Brocket Hall. My informant, Mr. Henry 

 Lewis of St. Albans, tells me it is not so abundant as it used to be, and 

 he is of opinion that the young are eaten by the trout which he says are 

 more numerous than formerly. The crayfish appears to be very local. 

 Although fairly common in the Lea, I cannot hear that it has been found 

 in the Ver, although both streams rise from the chalk and flow through 

 similar country within a few miles of one another. Both Mr. Lewis 

 and his brother, Mr. Arthur Lewis, have tried without success to intro- 

 duce it into the Ver. Mr. Arthur Lewis says he once turned one hundred 

 dozen into the Ver near St. Michael's Mill, St. Albans, but they seem 

 to have entirely disappeared, only one, which was subsequently taken 

 in an eel trap, having since been seen.' Facilities for obtaining the 

 species in question are of no little value, since a mastery of the details 

 of structure in this one typical form may be made the basis, as Huxley 

 has shown, of a sound zoological education. Such a mastery will cer- 

 tainly be helpful in an extraordinary degree to any one who wishes to 

 examine crustaceans in general and the Malacostraca in particular with 

 an understanding mind, and with insight prepared to find something like 

 order and unity of plan in the mighty maze of their innumerable diver- 

 sities. It is worth remarking that the technical name of the species is more 

 correctly given as Potamobius pallipes, reserving the generic name Astacus 



1 Trans. Herts Nat. Hist. Soe., edited by John Hopkinson, F.L.S., F.G.S., vol. ii. p. 136 (1884). 

 * Tram. Watford Nat. Hist. Sac., vol. ii. p. 126 (1879). 



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