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 CRUSTACEANS 1847, but that is itself a synonym of the much eadier Praunus, Leach. Metzger quotes Mysis spimfera. Goes, as a synonym of Gastrosaccus sanctus, but it is now known that these two species are distinct, G. spinifir having the concave hind margin of its carapace prettily fringed with eight sharp denticles, which are not present in the other species. From Praunus this genus is distinguished by the very great development of the side-plates in the first pleon segment. All the three species men- tioned agree in having the telson apically divided. Thus they are separated from a fourth species in the same family, Siriella armata (Milne-Edwards), of which a specimen was found by Mrs. T. R. R. Stebbing, cast up among hydroids on the north beach, Lowestoft, in May 1907. This species has a very long sharply-pointed rostrum, agreeing in this respect with S. frontalis (Milne-Edwards), but separated from it by the scale of the second antennae, which in S. armata is distally much narrower, and by the armature of the telson, wherein the marginal spines are less unequal and the larger are separated from one another by less numerous small ones. The apical spinules are three or' four in number. The Edriophthalma or sessile-eyed Malacostracans offer a few points of interest in the fauna of Suffolk. In the order Isopoda, tribe Flabellifera, family Sphaeromidae, Mr. Claude Morley reports Sphaeroma longicauda. Leach, from brackish water, Trimley Marshes. Leach, in establishing a second species, S. hookeri, at first speaks of it as ' discovered by Mr. W. J. Hooker on the Norfolk coast,' " but later writes, ' Habitat in Suffolcii ad littora maris ; color cinereus aut rufescens, punctulis nigris sparsus. Cum copii crustaceorum benignissime communicavit amicus W. J. Hooker, cujus nomen gerit.' '* It is tantalizing to think of the light which might have been thrown on the carcinology of this county by the families of Dawson Turner, James de Carle Sowerby, and William Jackson Hooker, had not their passing interest in it been diverted to other branches of natural history. As to the two species it is no longer quite certain that they ought to be retained in the genus Sphaeroma^ and it is a little uncertain whether they should be specifically separated one from the other. In the same tribe the family Limnoriidae contains the widely distributed gribble, which Leach in 1814 called Limnoria terebrans. He says of it, 'This new and highly interesting species was sent to Dr. Leach by Mr. Stevenson, from the Bell Rock, in logs of wood, which it perforated in the most alarming manner. He has since received it from the coast of Suffolk.'" Kirby and Spence in their Introduction to Entomology, published in 181 5, had already paid much attention to injurious insects, but without any notice of the gribble. For this, which they evidently considered a serious omission, they endeavoured to atone at great length in an Appendix issued the very next year. Therein it is stated, ' The Linnean order Aptera furnishes another timber-eating insect, a kind of woodlouse (Z,/OTnor/'a terebrans of Dr. Leach), which in point of rapidity of execution seems to surpass all its European brethren, and in many cases may be productive of more serious injury than any of them, since it attacks the woodwork of piers and jetties constructed in salt water, and so effectually as to threaten the rapid destruction of those in which it has established itself In December last I was favoured by Charles Lutwidge, esq., of Hull, with specimens of wood from the piers at Bridlington Quay which woefully confirm the fears entertained of their total ruin by the hosts of these pygmy assailants, that have within a few years made good a lodgement in them, and which, though not so long as a grain of rice, ply their masticatory organs with such assiduity as to have already reduced great part of the woodwork into a state resembling honeycomb.' '''^ Further on the writer says, ' The inhabitants of Bridlington Quay believe that this insect was left there, a few years ago, by an American vessel, with what foundation I know not : but that it is an imported insect, and, like the Teredo navalis, not originally an European animal, seems very probable, from the fact that I can find no description of any species of Oniscus at all resembling it prior to that of Dr. Leach, who seems first to have given it a name [Linn. Trans, xi, 371), and it appears highly improbable that, if it had been an European species, it should not long since have attracted attention and been described.'^' It was rather late in the day for these distinguished entomologists to be treating this creature as an insect. As a matter of fact it had been described in 1799 by J. Rathke as Cymothoa lignorum, the generic name clearly indicating that it was known on the Continent to be a marine crustacean. Three kindred species from various parts of the world have since been described. How and when Limnoria lignorum was first introduced into Great Britain it might not be easy now to ascertain. It is unsafe to argue that it was not living and working among us, because no one had said anything about it till the combined efforts of Robert Stevenson and Dr. Leach made it notorious. In the tribe Valvifera the family Astacillidae contains Jstacilla longicornis (Sowerby) of which a specimen dredged off Yarmouth was given me several years ago by Dr. G. S. Brady. In the family Idoteidae Metzger reports Idotea tricuspidata, Desmarest, from Yarmouth Harbour.^^ By this name is probably intended /. halthica (Pallas), which is everywhere common on our coasts. " Edinb. Encycl, vii, 433. " Trans. Linn. Soc. (1815), xi, 369. " Editib. Er.cycl. vii, 433. '" Op. cit. 17. " Ibid. 19. " Hordicefahrt Pomm. 285. 157