290 The Irish Naturalist. 



The distribution appears not to be limited to Europe. I have records 

 for Hungary (CE^rley, A Magyar. Olig. Faunaja, 1880), France, Italy, 

 Tenenfte, Germany, Bohemia, Scandinavia, England, Valparaiso, etc. 

 Mr. Beddard says : " Allurns tetra'edrus must be regarded as a rather uncer- 

 tain North American form. I have included it in the list (of Nearctic 

 worms) on the strength of a specimen kindly sent to me some time since 

 by Mr. Tyrrell, of the Canadian Geological Survey. I examined this 

 specimen by means of longitudinal sections, and identified it with Allurus 

 on account of the structure of the gizzard."* In Britain it is ubiquitous. 

 I have found it in, or received it from Sussex, Kent, Essex, Suffolk, 

 Devonshire, Gloucestershire, Yorkshire, Lancashire, Wales, Ireland, 

 Scotland, and elsewhere. It may almost without exception be found 

 wherever water occurs — by ditches, ponds, streams, rivers, and lakes, 

 usually in considerable numbers. The soil, however, has some influence 

 on the worm ; clay and iron are eschewed. 



Respecting the varieties which exist it is at present difficult to speak 

 with certainty. Eisen gives two, which Q^rley includes in his Hungarian 

 list, and I have found others which will merit attention when the subject 

 has been more fully worked. Colour alone is not a sufficient test, and 

 we do not know how far the girdle and tubercula pubertatis may be liable 

 to variation without affecting the species. 



1. A. tetraedrus, var. luteus, Eisen — Body sienna-brown, yellow ventrally. 

 Girdle warm yellow or pale cinnabar-red. I find this variety chiefly in 

 sandy or gravelly beds, somewhat widely distributed. 



2. A. tetraedrus, var. obscurtcs, Eisen — Body grey-brown, with pale 

 ventral surface. Girdle of the same colour as the rest of the body, 

 or somewhat lighter. Seems to prefer roots of grass by the sides of 

 streams and ditches in meadow or pasture land. It is as common as the 

 type, and may owe its colour simply to its environment. In this case we 

 have an interesting question yet to solve. What can be the value to the 

 worm of this mimicry ? 



Distribution in IreI/AND. — Malahide, Co. Dublin (Mr. Trumbull); 

 Cash el, Tipperary (Lt.-Col. Kelsall) ; Carrablagh, Co. Donegal (Mr. Hart). 



[2. Allurus amphisbacna, Duges — Though the majority of writers 

 have confused this species with the last, Rosa and Eisen have already 

 pointed out the fact that the characters are widely different. I had also 

 come to the same conclusion long before seeing the remarks of these 

 careful investigators. Duges first described the worm in 1828 under the 

 title Enterion aniphisbcsna. His reason for adopting the latter name is to be 

 found in the fact that this worm (like the one already described, and, in 

 a lesser degree, Ltimbricus purpiireus, Eisen) can go as readily backwards as 

 forwards, after the fashion of the serpent of which Lucanus sang. Nine 

 years later (in 1837) Duges returned to the same subject, and he now 

 affirms that his worm is quite distinct from that of Savigny. He there- 

 fore named the one Ltanbricus tetraedrus and the other Ltimbricus atnphis- 

 bcena, and gave a clear diagnosis of each. A. amphisbcena differs from the 

 other in the following particulars : — There are fewer girdle segments, 

 the colour, size, and shape differ, and, above all, the insertion of the lip 

 into the peristomium is quite dissimilar. If Eisen's diagnosis were 

 pressed we should have to put this worm with the genus Lumbricus ; but, 

 just as one of the Dendrobcenoe has the head of a Lumbricus, with all the 

 other characters of an Allolobophora, so this worm has all the characters of 

 an Allurus, with the head of a Ltimbricus, Eisen's lip and peristomium 

 arrangement, therefore, falls through. A. amphisbcena, Duges, is a small 

 worm, with a crenulated tail, which is prismatic when contracted, and 

 the body colour is violet, with iridescence. The girdle occupies segments 

 23 to 28 (or 22-27), and the lip forms a perfect mortise and tenon with the 



1 " Proc. Roy. Phy. Soc.y Ed., 1891. Q. J. M. Sc, vol. vi., pt. II., p. 365 

 (1888). 



