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).
168
