CRUSTACEANS 



group above the level of the commonplace. The family Caligidae have a broad depressed carapace, 

 uncinate second antennae, second maxillae and maxillipeds ; the stiliform mandibles are included 

 within a suctorial beak ; the ovisacs are a pair of cord-like tubes. In the genus Ca/igus 

 (O. F. MUller), though not in that exclusively, the frontal border has a pair of ' lunulae,' often mis- 

 taken for eyes. Cocks gives the following record : Ca/igus diaphanus, Nordmann, cod and haddock, 

 fish market ; rapax, M. Edwards, haddock and whiting, fish market ; Miilltri, Leach, haddock, 

 cod, etc., fish market, with the remark added : 'It is the common opinion that it is the Ca/igi which 

 force the salmon from the sea up rivers towards the waterfalls, Moller.' The species which 

 especially attacks the salmon is Lepeophtbeirus salmonis (Kroyer), belonging to a genus devoid of frontal 

 lunulae, but Caligus rapax includes the salmon among its numerous victims. C. mutteri. Leach, 

 and C. diaphanus, Baird, are now accounted synonyms of C. curtus, O. F. M. 1 Cocks records 

 ' Pandarus bicolor. Leach. From the skin of the Carcharius g/eucus.' The name of the host should 

 be Carcharias glaucus. He gives ' Cecrops Latreillii, Leach, from the Orthagoriscus molae, by 

 Arthur Chard, jun., fisherman.' The specific name of the huge, strangely truncate sun-fish, on 

 which this large copepod is only one of many parasites, should be not mo/at, but ma/a. To this 

 family also belongs a remarkable parasite which Milne-Edwards described in 1840 as Phyllophora 

 cornuta, from a specimen taken at Tongatabu. The generic name alluded to the leaf-like plates on 

 the creature's back, but being preoccupied it has just been changed to Phyllothyreus by Norman, 

 who says : ' I may take this opportunity of announcing this interesting species as a member of the 

 British fauna. It has been known to me for more than forty years. It was sent to me by William 

 Laughrin at a time when I was employing that old coastguardsman to collect fish parasites for me. 

 He said that he had found it on the blue shark at Polperro.' a 



In the Chondracanthidae the males are minute, and the females have the body completely or 

 indistinctly segmented, often with irregular lobes and prolongations. To this family belong two 

 species recorded by Cocks as ' Lernentoma asellina. Linn., attached to gills of tub-fish (Trig/a 

 hirundo, House. Lophii, Johnston. From a Lophius piscatorius ; beach, near Boyer's cellars.' The 

 former has recently been placed in a new genus by Mr. Bassett-Smith, so that it now stands as 

 Oralien asellinus (Linn.) ; the latter is Chondracanthus loph'ti (Johnston). 3 I cannot find any 

 Mr. House as an authority on tub-fishes, and conjecture, therefore, that Cocks in the above quotation 

 could give no more precise locality for the fish than his own home at which he examined it. The 

 Lernaeidae, while young, even if sexually mature, are not specially abnormal, but ' in the older and 

 fixed parasitic condition the females are long, worm-like, generally without limbs, some with 

 irregular excrescences from the anterior portion, others with elongated appendages from the genital 

 segment or abdomen.' 4 Cocks reports ' Lerneonema encrasico/i, Turton, attached to the eye of a 

 young pollock, fish-stall, Back hill.' Bassett-Smith transfers this to the genus Lernaeenicus 

 (Lesueur), 6 a name which the author of the genus spells Lerneaenicus. Encrasicolus was Willoughby's 

 name for the anchovy. Lastly, Cocks gives ' Lernea branchialis, Linn. Removed from the gills 

 of the haddock, by Miss Vigurs,' adding : ' Kroyer states that he observed a singular phenomenon 

 when he touched an individual (L. branchialii) ; it squirted from the vent a transparent stream of 

 fluid to the distance of a foot and a half, and this it repeated several times one after another.' The 

 generic name as written by Linnaeus himself is Lernaea. The passage translated from Kroyer 

 occurs in the first volume of his Naturhistorisk Tidsskrift, p. 183, published in 1837. Kroyer does 

 not say that the Lernaea squirted a stream of fluid, but ' a clear fluid to a distance of a foot to a foot 

 and a half,' which brings the rapid repetition of the discharge within the limits of probability ; since 

 each volley might have been a few drops instead of a stream. 



The Thyrostraca or Cirripedes are no less indebted than the other groups of Cornish crusta- 

 ceans to the untiring zeal of Mr. Cocks. It is true that in 1850 he still included them among the 

 Mollusca. 6 But of this the explanation is simple, namely, that the volumes of Darwin's great 

 monograph were not published by the Ray Society till 1851 and 1854. It would naturally not 

 count for much in conservative England that our own countryman, J. Vaughan Thompson, had led 

 the way some twenty years earlier in proving barnacles to be crustaceans and not molluscs. We 

 must still be grateful to Mr. Cocks for his catalogue, the value of which is not really impaired by its 

 misplacement in classification. The simplest way of dealing with it will be to interpolate in square 

 brackets the names preferred by Darwin in his monograph, and supply occasional notes. Of the 

 sessile Thyrostraca, Cocks gives the following list : ' Genus Balanus. Balanus communis, Mont. 

 [B. perforates, Bruguiere], On rocks, stones, etc., Barpoint, Castle, Gwyllyn-vase, Swanpool, etc., 

 common ; very large on the Black rock, from f of an inch, to i of an inch in length. /aevis, 



1 See Bassett-Smith, Prof. Zoo/. Soc. Land. (1899), p. 447. 

 * Ann. Nat. Hilt. (1903), Ser. 7, vol. xi, 368. 



3 Proc. Zool. Soc. Land. (1899), pp. 490, 494. 4 Ibid. p. 480. ' Ibid. p. 484. 



6 'Contributions to the Fauna of Falmouth,' in The Seventeenth Annual Report of the Roy. Ccrntv. Polyt. Soc 

 1849, pp. 75-77- 



287 



