Page:VCH Surrey 1.djvu/236

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A HISTORY OF SURREY in length, which is an enormous size for a Dapbnia.' 1 Judging by the size alone it is tolerably safe to infer that the species intended is Dapbnia magfia, Straus. Mr. D. J. Scourfield indeed has noticed that ' this, the largest species of the genus, seems to be almost solely an inhabitant of little duck-ponds.' But as the area of duck-ponds is apt to vary with the drought or moisture of a season, the dimensions of the pond on Mitcham Common need not be thought prohibitive. Among objects found on the excursions of the Quekett Club D. schafferi is recorded from Richmond Park, and though no authority is given this is doubtless intended for the species so named by Baird, which is a synonym of D. magna. Also the same club records from Richmond Park a ' Daphnia male, very large, body 2 mm. long.' In correspondence with these measurements M. Jules Richard gives 2-2*2 mm. as the length of the male D. magna, and 4-5 mm. as that of the female. 2 Dr. Brady has recently transferred this species to a new genus named Dacty/ura, ' finger-tail,' in allusion to a finger-like lobe in front of the terminal unguis ; but this is strictly an entail male, the female not having any such finger-like lobe.* After a mention of Daphnia pulex another species is rather vaguely described, among objects found by the Quekett Club at Woking, as ' a Daphnia probably reticulata of Baird's British Ento- mostraca having the eye at the end of a blunt rostrum.' 4 The D. reticulata of Baird's work is now divided between two species, Cerio- dapbnia reticulata (Jurine) and C. mega/ops, Sars, in this genus the first antennae of the female being movable, whereas in the same sex of Daphnia they are immovable. In the same family stands Moina recti- rostris (O. F. Mu'ller), which is one of the species bred from the dried mud taken at Headley. When alive this little transparent creature is beautiful under a lens. The pink colour is visible even to the unaided eye, but a slight magnification shows this to be due to the round pink eggs, neatly arranged in two parallel series, three in a row. It is also recorded from this county by Dr. Brady on the authority of Mr. Scour- field. 6 In the extensive family of the Chydoridae the waters of Surrey are well provided with species. It has two belonging to the genus Chydorus, Leach, which gives its name to the family. One of these, the very small and very common C. spbcericus (O. F. Miiller), was bred from the dried mud procured at Headley ; the other, C. globosus, Baird, is recorded by Dr. Baird from a ditch near Richmond, with the obser- vation that it is to be met with in 'June, July, August and September, but rare, and confined apparently to small patches.' He describes it as having the 'shell quite globose, a good deal resembling in form the preceding species, but more completely rounded, and nearly six times 1 Proceedings and Transactions of the Croydon Microscopical and Natural History Club, p. 8 (1884- 1886). 2 Ann. Sci. Nat. ser. 8, vol. ii. pp. 193, 195. 3 Nat. Hist. Trans. Northumberland, Durham, and Nttvcastle-ufon-Tyne, vol. xiii. pt. 2, p. 240.

  • Q. M. C. ser. 2, vol. ii. p. 34.
  • Nat. Hist. Trans. 'Northumberland, etc. vol. xiii. pt. 2, p. 245.

194