A HISTORY OF LANCASHIRE 



well rid of its argulid parasites.' ^ The late Professor Claus, in reference to 

 the similar habits of European species, applied to them the term ' intermittent 

 parasites.' In his opinion, however, it is not so much breeding as a surfeit 

 of feeding that induces them to leave their living tables. 



A much more numerously represented and more familiar sub-order, the 

 Cladocera or an tiered branchiopods, derives its name from the character of 

 the second antenna, w^hich are as a rule two-branched, with setas on the 

 branches to augment their swimming power. To prevent our being too 

 presumptuously sure of anything, nature is fond of introducing unexpected 

 exceptions. Accordingly, there is one very singular member of this group, 

 Holopedium gibberum (Zaddach), reported by Mr. Conrad Beck from Lake 

 Windermere,' in which the female has the second antenna not branched 

 but simple. This species belongs to, and in fact of itself in this county 

 constitutes, the family Holopediidas, having the animal remarkably clothed 

 in a very large gelatinous involucre. The remaining records belong to a 

 different section of the Cladocera and are distributed among three families. 

 All the names appear to have been supplied to Byerley by Mr. W. H. 

 Weightman, whose notices will be quoted, with occasional comments made 

 necessary by changes in technical nomenclature since Byerley's work was 

 published. The accepted authority for each species is also here appended, 

 there being a fair general probability that the specific names given by 

 Mr. Weightman were correctly identified. In the family Daphniidae, we 

 have Daphnia pulex (de Geer), ' in various ponds and ditches; sometimes, 

 when of a red colour and very numerous, giving the water quite a blood-like 

 tinge'; D. vetula, now called Simosa vetula (O. F. Miiller), 'occasionally met 

 with both in Wirral and Lancashire : in ponds at Litherland and Scaris- 

 brick ' ; D. rotunda, now Ceriodaphma rotunda (Strauss), from 'ponds in 

 Lancashire.' In the family Bosminidae, Bosmina longirostris (O. F. Miiller) 

 has been observed ' in the brook that divides Seaforth from Litherland.' In 

 the family Chydorids, often erroneously called Lynceidae, Mr. Weightman 

 thus notices the little universally distributed Chydorus sphcericus (O. F. 

 Miiller): 'Pond near Woodchurch, June, 1852. Has bred freely in my 

 Vallisneria jar. — Pond at Roby.' On Acroperus nanus, now Alonella nana 

 (Baird), the remark is made, ' Mr. Weightman met with one specimen at 

 Aintree bearing much resemblance to this species, but larger than it is 

 described in Baird's work.' He found Alona quadrangularis (O. F. Miiller) 

 ' in the Litherland neighbourhood ' ; Pleuroxus trigonellus (O. F. Miiller) 

 ' tolerably plentiful in the same pond with the last species, l)ut none of the 

 specimens were striated as ih Baird's British Entomostraca ' ; Peracantha 

 truncata (O. F. Miiller), at 'Waterloo, October, 1851.'* The ephippium 

 or case in which the winter egg of Bosmina longirostris is sheltered during its 

 resting stage has recently been described by Mr. D. J. Scourfield, and shown 

 to differ in some respects from the better known ephippium of the 

 Daphniidse.^ 



A few Ostracoda are catalogued by Mr. Weightman as belonging to this 

 county. He names Cypris nionacha from Waterloo, C. minuta from Roby, 



1 Bulletin of the Bureau of Fisheries, Washington, 1904, xxiv. 118. 



2 Joum. R. Microscopical Soc. (Ser. 2), iii. 780 (1883). * Fauna of Livetfool, 53, 54. 

 * Journ. Quekett Microscopical Club (Ser. 2), viii. 51 (1901). 



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