CRUSTACEANS estuary of the Thames, and from the same locality C. tenera, Brady ; C. albomaculata, Baird, taken at Whitstable by Rupert Jones, at Girdler Sand (Thames) and Margate by E. C. Davison ; C. gibbosa, Brady and Robertson, found by those authors in the Thames Estuary ; C. tuberculata (Sars) from Margatei; C. villosa (Sars), obtained by Davison at Margate and Girdler Sand; C. navicula (Norman), of which Brady recognized his Cythere Jidicula as a synonym, from the estuary of the Thames and various other places, but in all of them rare, with a specific name suggestive of the form, which Norman thus describes, 'ventral aspect boat-shaped, the resemblance most striking ; centrally depressed at the juncture of the valves; bow moderately sharp, of good breadth of beam, sculptured with raised, threadlike concentric lines, representing the timbers, while the small nodulous processes stand for the thole-pins. The dorsal and end views bear out the illusion, the former representing a boat viewed from below, with a well-marked keel, and the latter being triangular, with gently rounded sides ; ' C.fuscata, Brady, found by Brady and Robertson in the Thames,^ C. antiquata Baird from the Thames^ and C whitei (Baird) from the Girdler Sand.* Cytheridea papulosa. Bosquet, has been found in the Thames Estuary, by Davison, and of the same genus C. elongata, Brady, in Peg- well Bay by Rupert Jones, and in shell sand from the Thames by Dr. Brady ; C. torosa (Jones) has been found at Gravesend by Professor Jones, at Girdler Sand by Davison, and in shell sand from Pegwell Bay by Brady ; C. lacustris (Sars) was obtained from the Thames Estuary by Brady and Robertson.* Eucythere declivis (Norman), of which E. argus (Sars) is a synonym, is recorded from ' Girdler Sand,' this like most of the specimens from that locality having been collected by Mr. E. C. Davison. Loxoconcha impressa (Baird) ' in the shell sand from the Girdler Sand' (Thames) ' is described as one of the commonest of British species.' The generic name means ' oblique shell,' and in accord with this Dr. Brady observes, ' the genus is well characterized by the oblique " peach-stone " outline of the carapace.' To the same genus belong L. guttata (Norman) from Girdler Sand, Thames, and ofFDungeness Bay; L. viridis (O. F. Miiller), of which L. elliptica, Brady, from Girdler Sand, is now recognized as a synonym ; and L. tamarindus (Jones) from Margate and ' in shell sand, Girdler Sand.' Xestoleberis aurantia (Baird) is reported by Brady and Norman from the estuary of the Thames and from ofFDungeness Bay. This species shows 'colour deep brownish orange, or sometimes white ; a very conspicuous black or deep crimson spot in front of the eyes.' The genus. Dr. Brady says, 'is chiefly distinguished by the peculiar form of the carapace, which is very low and pointed in front, elevated and tumid behind, in these respects offering a direct contrast to the genus Eucythere' It has the ' shell very smooth and polished, ornamented with small round distinct » Brady and Norman, Transactions Roy. Dublin Society, ser. 2, iv. 143. » Loc. cit. iv. 148. 3 Loc. cit. 168. ♦ Loc. cit. 169. • See Monograph of Post-tertiary Entomostraca, 179 (1874). I 237 33
