Page:VCH Cornwall 1.djvu/336

 A HISTORY OF CORNWALL as a new species, 1 to which also they assign C. sarsii, Brady, local variety, while the original C. sarsii, Brady, is made a synonym of C. similis, Sars, without being localized in the Scilly Islands. The new species C. fulva, Brady and Robertson, ' dredged pretty abundantly on a bottom of hard granite mud, in a depth of 1040 fathoms, off St. Mary's and St. Agnes,' has since been taken in ' Fowey Harbour, 3 and 4 fathoms,' and off the Eddystone Lighthouse. 2 C. flavescens, Brady, and C. cuneata, Brady, have both been since identified with the earlier C. sella, Sars ; and C. cornuta, Brady, is accepted by Brady and Norman as covering Brady's C. gibba, which is distinct from O. F. Mailer's species that bears the same name. C. striata, Sars, C. angulata, Brady, C. products, Brady, taken also off the Eddystone ; C. acuticostata, Sars, and C. cellulosa, Norman, complete the enumeration in the genus Cytherura. Pseudocythere (Sars) has its single species P. caudata, Sars, which has been taken also off the Eddystone. 3 Cytheropteron (Sars) contributes C. /atissimum (Norman), C. nodosum, Brady, and C. subcircinatum, G. O. Sars, which Brady and Norman find to be wrongly identified, and therefore substitute for it C. depressum, n. sp.* Both this and C. nodosum have also been found off the Eddystone. Bythocythere (Sars) yielded B. constricta, Sars, and B. turgida, Sars, both common also to the Eddystone. Cytherideis (Rupert Jones) is represented by a large black-banded local variety, fasciata, of C. subulata, Brady ; Sclerockilus (Sars) by S. contortus (Norman), and Cytherois (G. W. Mttller) by C. fischeri (Sars), which the list places under the next genus. In G. W. Mtiller's opinion the family Paradoxostomatidae should not rank higher than a sub-family of the Cytheridae. The genus Paradoxostoma (Fischer), in the list under discussion, has the species P. abbreviatum, Sars, P. variabile (Baird), P. ensifirme, Brady, P. cuneatum, n. sp., of which the authors say : 'A few specimens of this species were dredged at New Grimsby Harbour and inside St. Mary's in depths of from 10-15 fathoms,' but Brady and Norman identify it with the earlier P. orcadense, Brady and Robertson, from the Orkneys, saying : ' The Scilly specimens are smaller and more angular than the types, and were at first supposed to be distinct (described as P. cuneatum), but further examination leads us to conclude that they belong properly to P. orcadense.' 6 The remaining species are P. hibernicum, Brady, P. normani, Brady, the rare P. arcuatum, Brady, P. flexuosum, Brady, belonging also to the Eddystone ; and lastly P. obliquum, Sars, reported further by Norman from Mylor Creek, Falmouth. 6 Cocks records Cythere flavida, Mttller, from ' Minute Algae, etc., ponds on rocks, Gwyllyn-vase, west,' and Cythere variabilis, Baird, from the same localities. 7 Probably both of these are Paradoxostoma variabile (Baird). 8 Bate in his ' Revision ' names thirty-eight species of Ostracoda as ' dredged off the Cornish coast,' 9 but the species not included among those above recorded appear really to have been dredged rather off the coast of Devon than of Cornwall. To deal with the Copepoda of the county within any reasonable limits is exceedingly difficult. Their localities are known chiefly though Dr. G. S. Brady's report of them in his Monograph of British Copepoda, published by the Ray Society. On the classification of this order Dr. W. Gies- brecht is the leading authority, and, so far as it extends, the systematic index which he and Dr. Schmeil supply in the Copepoda (gymnoplea) of Das Tierreich (1898) may conveniently be followed. An ordinary copepod may be conceived as forming two compartments. There are eleven segments, the composite first being the head, the next five the thorax, and the last five the abdomen. Between head and thorax, however, there is so close a union that they together form the first compartment, the abdomen or pleon forming the second. But there is this peculiarity, that the middle segment is sometimes continuous with the broader fore-body, some- times with the narrower hind-body. In the former case the hind-body has no feet, but consists of the pleon pure and simple. The species so constructed are called Gymnoplea, meaning ' those that have the pleon bare,' that is devoid of feet. This group is divided by Giesbrecht and Schmeil into five families. In the first of these, the Calanidae, the males have both antennae of the first pair symmetrical or nearly so, acting as sense organs, whereas in the other four families one of the pair is geniculate, adapted for clasping the female. Mr. Vallentin reports from Falmouth ' Calanus finmarchicus, Brady,' 10 for which should rather be read C. finmarchicus, Gunner. To the next family Diaptomidae (Giesbrecht's Centropagidae) belongs ' Diaptomus castor, Westwood,' reported by Cocks from ' Pond, Panscouth lane,' n but whether this be Jurine's original Monoculus castor or an allied species cannot be decided. From the same family Vallentin records Centropages typhus, Kroyer, and Ttmora longicornis (O. F. Muller) in Falmouth waters, to which Brady adds Eurytemora affinis (Poppe), saying ' the Rev. Dr. Norman has sent me specimens from Swan Pool, I Trans. Roy. Dublin Soc., Ser. 2, vol. iv, pp. 230, 203. * Ibid. p. 206. 6 Ibid. p. 230. 7 Cornw. Soc. (1857), p. 17. 8 Trans. Royal Dubfin Soc. Ser. 2, vol. iv, 229. 9 Op. cit. pp. 73, 74. 10 Cormti. Soc. the Fifty-ninth Annual Report, 1891 (1892), p. 97. This reference applies to all the Copepoda recorded by Mr. Rupert Vallentin. II Ibid. 1856 (1857), p. 18. 284
 * Ibid. p. 225. 4 Ibid. p. 218. 5 Ibid. p. 234.