A HISTORY OF NOTTINGHAMSHIRE 



which have the telsonic segment more or less acute. All these five are included in the family 

 Oniscidae. Oniscus asellus (Linn.), as might be expected, is noted as the commonest species, and 

 as being 'abundant everywhere under flower pots in gardens, under stones, logs, bark of fallen 

 trees, etc.' J It reaches two-thirds of an inch in length and more than a third in breadth, the 

 eyes are rather large, and the second antennae have the five-jointed peduncle not armed with 

 outstanding spines as in Trichoniscus pusil/us, but smooth and carrying a flagellum of only three 

 joints. The third, fourth, and fifth segments of the pleon are expanded in such a way that 

 their lateral edges form a continuous curve with the sides of the middle body. By this last 

 feature it is easily distinguished both from the preceding species and from the next, which is 

 of a size somewhat intermediate between the two. This bears a name reminiscent of 

 summer glades, being by interpretation the shade-loving tenant of mosses, or technically 

 Philotcia muscorum (Scopoli). It is ' common under stones and logs everywhere around Not- 

 tingham ; also about Mansfield, Worksop, in Sherwood Forest, etc.' * Of Platyarthrus 

 ho/mannsfggii (Brandt), Professor Carr says, 'This curious little wood-louse differs from the other 

 British species in being quite destitute of eyes ; it is pure white in colour, and lives in ants' 

 nests, where its presence is tolerated probably on account of its being useful as a scavenger. 

 I have found it commonly in quarries throughout the Magnesian Limestone district, e.g., near 

 Bulwell Wood Hall, Grives Wood (Kirkby in Ashfield), Mansfield, Warsop, Creswell Crags, 

 and Worksop ; also in Wollaton brickyard ; and the Rev. A. Thornley has sent me specimens 

 from a gypsum pit at Clarborough, near Retford.' 3 The peculiar habitat and the characters 

 above given will enable the student when he comes across this widely distributed species to 

 imitate a celebrated traveller and say, without further introduction, ' Platyarthrus, I presume.' 

 Its supposed usefulness as a scavenger in the formicarium tallies with the service which 

 apparently the whole crustacean class are disposed to render to their fellow creatures. They 

 are a kind of living machinery for converting waste products into palatable foods. Porcellio 

 icater (Latreille) is reported as ' very common under stones and flower pots in Nottingham 

 gardens, also under stones and logs, under bark of dead trees, etc., throughout the county. 

 The usual colour is a greyish slate, but a yellowish or reddish brown variety is not 

 uncommon.'* This very common species is nearly as long as Oniscus astl/us, but not so broad, 

 and is distinguished by its more granular integument, and by having the flagellum of the second 

 antennae two-jointed. Moreover, the two first pairs of appendages in the pleon exhibit an 

 interesting feature of distinction, in that the outer branches which form opercular plates are 

 provided with air cavities known as pseudo-tracheae. These must be regarded as a character 

 acquired since the ancestral Porcellio left the water for terrestrial wandering. In his essay on this 

 species the learned doctor and professor G. R. Treviranus 6 confirms the observation previously 

 made by de Geer that the Oniscidea feed on plants, and take their nourishment principally by 

 night. This is in accord with what I have suggested above as the custom of crayfishes. 

 Treviranus adds, however, ' In my hotbeds I often saw these creatures still late in the 

 morning gnawing at the leaves of the plants.' 6 Besides P. sealer several other species of this 

 genus are found in England, and some of these are sure to be eventually discovered in this 

 county. Indeed, since this prediction was written, it has been in part fulfilled, as will 

 presently be noticed. Of Metoponorthus pruinosus (Brandt), Professor Carr writes, ' I have only 

 once met with this species, on 22 June, 1902, when it occurred in considerable numbers 

 under a log in a garden at Sherwood Rise, Nottingham.' 7 This species recalls the appearance 

 of Philosda muscorum by having the pleon abruptly contracted. But it agrees with Porcellio in 

 having *a two-jointed flagellum to the second antennae, and air cavities in the pleopods. In 

 contrast with his single record for this species, Professor Carr speaks of Armadillidium vulgare 

 (Latreille) as occurring in considerable numbers in several localities, e.g., Nottingham, Kim- 

 berley, quarry near Bulwell Wood Hall, Mansfield, Warsop, Creswell Crags, Worksop, etc. 

 ' This species,' he adds, ' when disturbed instantly rolls itself into a perfect ball of the size and 

 colour of a black, or rather blue, pill ; hence the name " Pill woodlouse," commonly applied 

 to it. Varieties of a brown or yellowish-brown colour are not uncommon.' 8 It belongs to the 

 family Armadillidiidae. It has the telsonic segment truncate as in Trichoniscus pusi/lus, but, 

 whereas in that species the two slender branches of the uropods extend beyond the telson 

 quite prominently, here the inner branch is entirely concealed, and the short broad outer 

 branch helps to form a continuous curve with the telsonic and three preceding segments. To 



1 Op. cit. p. 2. s Ibid. p. 2. 8 Ibid. p. 2. 



* Ibid. p. 2. 6 yermischte Schriften, i, 50(1816). 8 Ibid. p. 53. 



^ Trans. Nott. Nat. Sac. for 1902-3, p. 2. " Ibid. p. 2. 



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