296 



SCIENCE-GOSSIP. 



moulting is given in Mr. Casserley's own words : — 

 "The first sign of the approaching change is the 

 appearance of a white border to each segment of the 

 body, which gradually becomes more marked. The 

 animal by this time is much less active, and usually 

 forms a small burrow to rest in. If it does chance to 

 leave this, it is only for a short time, invariably 

 coming back again to the same place. In some 

 cases no burrow is formed at all, a sheltered corner 

 against a stone being protection enough in the 

 creature's opinion ; but each woodlouse keeps to the 

 place it originally selected. 



' ' Ten days more or less after the w^hite lines on 

 the edges of the plates have become visible a very 

 curious change is apparent — the animal appears to be 

 divided into two. As is well known, there are seven 

 leg-bearing segments, and the first four of these and 

 the head appear as if they had coalesced to form one 

 large segment, while the remaining three and the 

 abdominal divisions have done the same. The 

 original segmentation can of course still be made 

 out ; but the joints are all fixed, with the exception 

 of that between the fourth and fifth leg-bearing 

 segments, which remains movable. 



" The woodlouse continues in this state for from 

 one and a half to two days, and then, suddenl)- walk- 

 ing forward, frees itself fi-om the covering of the 

 hinder portion of its body, carefully drawing the last 

 three pairs of legs from their old skin. The part 

 thrown off is perfectly white in colour, and is a very 

 pretty object indeed ; the jointed casings of the legs 

 being beautifully perfect, and made up of delicately 

 thin glass-like substance. As is usual, the lining of 

 some internal tubes are cast with the skin. Just 

 before this throwing-off of the parts mentioned, the 

 whole body seems to swell and lake on a light blue 

 colour. 



" Having got so far the woodlouse, after putting 

 his somewhat tender half well into his corner or 

 burrow, proceeds to make a meal off his cast skin. 

 He now has a very odd appearance. Excepting that 

 the white edges are most marked, the front part ot 

 his body retains its original form, size, and colour ; 

 while behind he is of a light slaty-blue, very soft, and 

 in proportion a little larger. After three days or so 

 the tail end has become fairly hard, and attained the 

 normal colour ; then the skin of the front half is 

 pushed off. At this stage the animal is in the most 

 precarious condition in which he ever finds himself. 

 All his fighting parts are soft and defenceless, and 

 any of his species that happen to be near make a 

 feast off him, eating all the front half and rejecting 

 the now hardened tail end. 



"Supposing the moulting woodlouse to have escaped 

 this danger— and in captivity only isolation from his 

 fellows will give him a chance— in about three days 

 his jaws are sufficiently hardened to allow of his 

 eating something, which is always his old clothes, as 

 in the first half of the moulting process. In young 

 specimens the operation does not occupy quite so 

 long a time. Specimens half an inch long do not 



moult oftener than once in six months, and but little 

 increase in size is noticeable after the process." 



Mr. Casserley alludes to the way in which the 

 woodlouse passes the winter. It can hardly be said 

 to become torpid ; but when cold weather comes on, 

 it remains exactly as it happens to be. If left alone, 

 and there is sufficient moisture, it will not move at 

 all until the temperature is raised. On the slightest 

 disturbance the animal becomes quite as lively as in 

 summer-time for a few minutes, and then settles 

 down again. 



As to the daily life in captivity of the creatures 

 under discussion, it was found that they are inclined 

 to be quite still during the morning, and it is not 

 until about five o'clock in the afternoon that they 

 move about much. As night approaches their liveli- 

 ness increases, until they walk about quite rapidly. 

 Each individual chose some particular part of the 

 cage in which to rest during the first part of the day, 

 to which it invariably returned, never usurping that 

 of another. 



Mr. Casserley had something to say with regard to 

 centipedes and millipedes, and concluded with re- 

 marks upon his observations. He seems to have 

 somewhat suddenly given up the work, which is a 

 great pity, seeing that there is so much to be done, 

 and that he had not succeeded in seeing the first 

 moult of the young woodlice. For the benefit of 

 those who may be inclined to interest themselves in 

 our terrestrial isopods, I may add something with 

 regard to the number of British species of woodlice. 

 Dr. Scharff ("Irish Naturalist," vol. iii. pp. 4-7 and 

 25-29) gave brief descriptions of seventeen species 

 in 1894. Last year the Rev. Canon Norman ("An. 

 Mag. Nat. Hist.," ser. 7. vol. iii. pp. 70-78) enume- 

 rated twenty species', and in the current number of 

 the "Essex NaturaUst" (vol. xi. p. 127) the present 

 writer records an additional one. Hence the number 

 of known British species is twenty-one. 



In conclusion, the writer wishes to say that he 

 would be glad of any specimens of woodlice that 

 those interested in the subject may feel disposed to 

 send to him. The specimens, small and large alike, 

 should be put into methylated spirit directly they are 

 captured, and the containing tubes or bottles, which 

 should not be large, enclosed in a tin box for transit. 

 The habitat and locality should in all cases be 

 noted. 



2 The Broadway, Haniinersmith. 



Survivals from Cambrian Times. — The dis- 

 tribution of animals and plants varies considerably, 

 some forms being confined to one formation, or, 

 indeed, to one zone, whilst others have had an ex- 

 tended range. Amongst the latter are the orders 

 Spongida and Crinoidea ; the moUuscan families, 

 Orthidae, Lingulidae, Arcadae, and Nuculidae ; all 

 of these dating from Cambrian times to the present 

 period. Often those that have a long range in time 

 also have a wide distribution in existing seas. Such 

 is the Lingula, which now lives off the coasts of 

 Japan, China, the Sandwich Islands, the Philippines, 

 and Australia. — Edward A. JMartin. 



