Page:VCH Northamptonshire 1.djvu/140

 A HISTORY OF NORTHAMPTONSHIRE not from canthos, which means a pack-ass, the apple of an eye, or the felloe of a wheel. The specific name of the Northamptonshire species alludes to a character mentioned in the description of the terminal furca, of which Dr. Brady says, ' caudal segments about as long as broad, bearing three stout marginal spines, and two plumose apical sets.' Among the little bivalved Ostracoda a few species have been tracked to this county by some of our keenest masters of research, Dr. Brady, Canon Norman, and the late David Robertson of Cumbrae. They are as follows : Prionocypris serrata (Norman). This species, after passing through the genera Cypris and Erpetocypris or Herpetocypris, has recently been placed by Brady and Norman in a new genus, Prionocypris, meaning the Cypris with a saw, so named because the extremities of the valves are more or less denticulately serrated. Brady and Robertson are the authorities for its capture in the river Nene at Peterborough.^ Cypridopsis mwtoni, Brady and Robertson, is also found in the river Nene. It has a coarsely hispid surface, is dull green in colour, and attains a length of '85 mm., that is, about a thirtieth of an inch.* Cypridopsis variegata, Brady and Norman, from the river Nene at Peterborough, was long left undescribed, because of its close resemblance to the preceding species, but its valves are less uniform, its length is only •55 mm., little over a forty-fifth of an inch, and at least in some speci- mens the ground colour is yellowish, and it is ornamented with black bands.' Candonopsis kingsleii (Brady and Robertson), taken in the river Nene at Peterborough, was transferred from Baird's genus Candona to a new genus Candonopsis by the Bohemian writer Vavra, from whom Brady and Norman quote the following generic characters, ' Antennae six-jointed, with two peculiar sense organs between the fourth and fifth joints. Mandible palp very long. Second maxills with a trisetose branchial plate. Caudal rami slender ; seta of the dorsal margin absent.' * These characters are taken from the male sex alone. Candona Candida (Miiller), of the variety tumida, is mentioned by Brady and Norman as being found in the river Nene.* This variety, they say, ' is much shorter and stouter than the typical form,' and in regard to distribution they observe that ' the ordinary form of C. Candida occurs commonly in ponds and ditches ; the variety tumida is most common in rivers and dykes subject to tidal influence.' In Candona, as defined by Professor Sars, the second antennae are four-jointed in the female, five-jointed in the male, with two sensory spines on the ante- penultimate joint. The mandibular palp is not very long, and the caudal rami have a slender dorsal seta.* Baird explains that he was induced to separate this genus from the old comprehensive genus Cypris 1 Brady and Norman, 'A Monograph of the Marine and Freshwater Ostracoda of the North Atlantic and of North-Western Europe,' part i., Trans. R. Dublin Soc, ser. 2, vol. iv. p. 87 (1889) ; and part ii., in ser. 2, vol. v. p. 724 (1896). ^ Loc. cit. part i. p. 91 ; part ii. p. 725. ^ Loc. cit. part i. p. 98. ^ G. O. Sars, Ostracoda Mediterranea, Arch. Naturv., vol. xii. p. 278 (1888). 106
 * hoc. cit. part i. p. 90 ; part ii. p. 725. * Loc. cit. part i. p. 102 ; part ii. p. 731.