A HISTORY OF CORNWALL 



segments with four carinae. The eyes and first antennae in this family are borne on movable 

 segments. The rostrum is articulated. The principal branchiae are attached to the pleopods. 



Before leaving the stalk-eyed Malacostraca the reader will no doubt welcome a quotation from 

 Jonathan Couch's History of the Fishes of the British Islands?- in which a discussion of the cod's 

 voracity includes an interesting contribution to our present subject. After mentioning several 

 strange miscellanea of its diet Couch continues : 



' In one instance six Picked Dogfishes, each 9 in. in length, were found in the stomach of a 

 cod ; and the following list of crustacean animals (crab and lobster kinds) in the stomach of these 

 fishes, which were taken in the west portion of the British Channel, will show the strong preference 

 which the cod manifests for that sort of food, of which also, we may add, their digestion is so 

 powerful and speedy, that, in a short time after being swallowed, the hard and brittle crust of the 

 crabs is made so soft by the action of the gastric juice, that their legs may be twisted round the 

 finger. 



' Crabs. Stenorynchus phalangium, Achaeus Cranchii, Inachus Dorsettensis, I. dorynchus, 

 I. leptochirus, Hyas coarctatus, Eurynome aspera, Xantho tuberculata, Cancer pagurus, Portunus 

 corrugatus, P. arcuatus, P. marmoreus, P. pusillus, P. longipes, Gonoplax angulatus, Atelecyclus 

 heterodon, Corystes cassivelaunus, Pagurus Bernhardus. 



' Long-tailed Crustaceans, lobster kind. Galathea squamifera, G. strigosa, G. dispersa, 

 G. Andrewsii, Munida Rondeletii, Gebia stellata, G. deltura, Nika edulis, N. Couchii, Squilla 

 Desmarestii, Alpheus ruber, Scyllarus arctus. 



' In this enumeration the notes of Mr. W. Laughrin, A.L.S., are united with my own ; and 

 of these species the Scyllarus arctus offered only one example, which is now deposited in the British 

 Museum ; but of the Munida Rondeletii, which is usually considered as not a common species, "there 

 have been found not only numerous specimens, but these have often been of remarkable size. The 

 longest leg of an example described by Mr. Bell in his beautiful Natural History of this tribe 

 measured 6 in., but I have found the same part to measure 9 in., with the antennae of the same 

 length as the leg.' 



Under the alternative names of Gadus morrhua and Morrhua vulgaris, the cod has been shown 

 also by Mr. Cocks to have a thoroughly carcinophilous palate, which it shares with the haddock, 

 the piper, the tubfish and many other gourmands. 



The transition to the sessile-eyed Malacostraca is not abrupt, since there is a small peculiar 

 group in which the eyes are sessile, but the affinities are nearer to the Podophthalma. To this order, 

 for some time known as the Cumacea, the name Sympoda has lately been applied. 2 Hitherto only 

 two species appear to have been noted from Cornish waters, though many more will certainly 

 be found therein when sought for with moderate diligence. Of Diastylis rathkii (Kr6yer) Bate says 

 ' It was first taken in Cornwall, at St. Ives, by the late Mr. Barlee. From Falmouth I received 

 it from Mr. Webster." He reports his own species Eudorella truncatula (Bate) from Plymouth 

 Sound. 3 In the former genus there is a very distinct telson, in the latter there is none. 



The other sessile-eyed orders, Isopoda and Amphipoda, though disregarded in Couch's 

 Cornish Fauna, not much later were collected with some diligence by Cocks, and in due course 

 attracted the notice of Couch and his son, and eventually, through the well-known work of Bate and 

 Westwood, to which Norman and others lent powerful assistance, they began to assume an 

 important place in the natural history of Great Britain. The economic value of little crustaceans is 

 perhaps seldom appreciated. Out of the multitude of aquatic animals we only use a few species 

 for food, and as a rule trouble ourselves little to consider how those animals themselves are nourished. 

 But, if, as above noticed, large fishes eat the larger crustaceans, small fishes eat the smaller, and 

 just as the strong mammals prey upon the weaker, so are the jaws of one shrimp nicely adapted 

 for masticating another. By a circuituous route the microscopic organisms of this class almost 

 undoubtedly render to mankind such services as our noblest philanthropists cannot hope to emulate. 



The genuine Isopoda, like the Squillidae, have the breathing organs in the pleon, but 

 there is a tribe of anomalous Isopods which have their respiratory arrangement in the front or 

 cephalo-thoracic part of the structure. This tribe is sometimes called Tanaidacea, sometimes 

 Chelifera. It comprises two families, the Tanaidae and Apseudidae. In these the heart is placed 

 near the head, as in the Amphipoda, instead of near the tail, as in other Isopoda. The first legs are 

 chelipeds, as in crabs and lobsters, but here there are seven pairs of trunk-legs instead of five, so 

 that the first pair correspond not with the chelipeds of a crab but with its second maxillipeds. 

 Of the Tanaidae, Bate and Westwood describe Tanais vittatus (Rathke) and T. dulongli (Audouin) 

 from Polperro, and Paratanais fonipatus (Lilljeborg) 4 from Plymouth Sound. Although the English 



1 Op. cit. (1864), vol. iii, 55. 



* Stebbing, in Willey's Zoological Results (1900, part v, p. 606), and Encyclopaedia Britannica Suppl. (1902), 

 Art. Malacostraca. 



3 ' Revision,' pp. 41, 42. 4 British Sen. Crust, vol. ii, pp. 125, 129, 138. 



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