SCIENCE-GOSSIP. 



325 



still remains for some little time quite without any 

 trace of bands, just as in young Limnaca, only that 

 in the latter case the shell rema : ns without 

 pigment permanently. 



In "Helix " a granular pigment occurs in the 

 epithelial and connective tissues, especially in 

 spring, and is related to the pigment of the shell f 33 ). 

 Mr. Bowell, some time ago, noticed pigment- 

 granules of various sizes in the fat-cells near the 

 heart in Limnaca, and in the leucocytes of Tachea, 

 and I can confirm the observation for the blood of 

 Cryptomfhalus . It is interesting in this connection 

 to note the relation which has been established 

 between the varied pigments found in the amoeboid 

 corpuscles and tissues generally of some Echinoder- 

 mata and the pigmentation of the shell in the same 

 group p»). 



The nature of these pigments when they get into 

 the shell (for there seems no improbability in 

 assuming a close connection between the body and 

 shell-pigments) f 35 ) is obscure. Krukenberg has 

 described the brown, red and yellow pigments as 

 " lipochromes " ; and has found what he calls 

 " biliverdin " in the shells of Haliotis, Turbo and 

 Trochus. I, however, very much doubt the pig- 

 ments of, say, Tachea or Anodonta being lipochromes 

 as usually defined ('-") ; they are not, so far as my 

 experience goes, soluble in alcohol, in which the 

 shells may be kept for a long time without 

 apparent alteration. Mr. Bowell tells me that the 

 brown in Succinea is exceptional in being partially 

 soluble in alcohol. It also seems very undesirable 

 that the name "biliverdin" should be applied 

 to a pigment when its identity with the well- 

 known vertebrate pigment, to which the name 

 belongs, has been by no means satisfactorily 

 established. C. A. Mac Munn (-") finds haemato- 

 porphyrin in the integument of brownish specimens 

 of Umax flavus and Arion ater, from which it may 

 be extracted with a mixture of rectified spirit and 

 sulphuric acid. A. atcr yields also to the same 

 reagent a black or greyish-black pigment, which 

 occurs microscopically in granules. In these 

 mollnsca enterohaematin (Sorby) is found in the 

 bile, so called, and histohaematins in various tissues 

 -_*ans J*), and the haematoporphyrin is a 

 metabolite of these. He considers that the 

 "haematoporphyrin of the slug's integument is 



an excretion (-■'), and possibly it may be of use at 

 the same time either as a sexual adornment or for 

 protective purposes." 



Haemoglobin is rare in mollusca. It occurs, how- 

 ever, in the general blood system of Planorbis (in 

 the plasma, not in corpuscles), and in the pharyngeal 

 and buccal muscles of Limnaea, Paludina, etc. ( s0 ). 

 It is very possible that certain products of these 

 pigments are used for shell-colouring. It is a very 

 noticeable fact that the whole genus Planorbis, and 

 especially P. corneus, are very frequently tinged 

 more or less deeply with red. As was mentioned 

 above, this colour is not a mere superficial in- 

 crustation, and whether the water is "ferruginous" 

 or not, P. corneus generally manages to become 

 somewhat erythric. It appears, in fact, as if this 

 genus had a special selective capacity for any 

 iron ( :fl ) in the water, which is especially developed 

 in P. corneus. But it is not unreasonable to 

 suppose that the haemoglobin contributes some of 

 the colour; this supposition is, I think, borne out 

 by the fact that the haemoglobin is more strongly 

 developed in P. corneus than in the other members of 

 the genus, as is evidenced by the fact that its egg- 

 capsules are very often coloured red by it ( 3i! ), 

 whereas they are colourless in the rest of the 



genus. 



(To be continued.) 



British Mosses. — Mr. E. Charles Horrell is 

 creating an interest in the distribution of British 

 mosses by inviting bryologists to assist him in pre- 

 paring a Moss Catalogue of the species in thes 

 islands, after the manner worked out for the flower- 

 ing plants by Watson in his " Cybele." This has 

 already been done to some extent in the second 

 edition of the "London Catalogue of British 

 Mosses " for the eighteen Watsonian provinces ; 

 but Mr. Horrell has made careful search through 

 the literature of the subject in magazines and 

 elsewhere, and finds there are still about sixty 

 Watsonian vice-counties in Great Britain with no 

 lists of the commoner species. Anyone who can 

 help in this investigation of ihe distribution of our 

 moss-flora should communicate with Mr. Horrell, 

 44, Brompton Square, London, and he. will furnish 

 particulars of the plan and what is wanted in the 

 way of lists. 



.'.Inden. Journ. Koy. Mlcr. Soc, 1896, p. 303. 

 A. Garnifte: ■• Physiological Chemistry, I. (1880), 



Ar'.h. d-- Physiol ' 



another tub.*- 1 



ihe llvr: b it I can obtain » 



detailed Infi tba point. 



■'. t.f , II. I. Newbi«ln, J',urn. of Physiol., >i. 

 . 



■ Mi- 

 I arm In Pi In |ourn ol 



(") e.i;., ihe pigments of some lopidoplcra (Plerldae) have 



down 10 be uric acid derivatives; Bee " The Pigments 



.,1 the Plerldae: a contribution to the Study of Excretory 



Substances which function as ornament. " F. G. Hopkins, 



Phil Trana. R. s., vol. 186 B. (1806), p, 661. 



1 1 E, K. Lankestcr: Proc. Koy. Soc, xxl. (1872), ]>. -1. 

 11 1 Sorby'i doubti aa to Ibe Identity of the red colouring 

 maitei 0! PlanorbU and haemoglobin are not shared l>y 



and A. Gamgce [op. til, p. n,u). I have got the NaCl 



1 .»- lulu reaction— from P. comcus 

 ■ , Perbap we too often assume tbal any red li dut i" 



u ii' !■ omethlng totally different. |,F.Wh ves 



10/ 1 1! i' 13) Implies '' ilinllai selection 01 a fernu >'. 



I 1 1 Hum ' 1 ult helium" 

 (") bpeciroscopkaily. by Mr. E W. W. Bowell. 



