40 The Irish Naturalist. 



Examined internally, the sperm-sacs in segments ioand n open into the 

 space between 9/10 and 10/11, in the direction of the fourth or dorsal setae. 

 In this respect it agrees with another species (A. turgida), with which 

 also it corresponds in other respects." 



I am bound to confess that many investigators would regard 



these two worms as simply varieties or sub-species, but this is 



no sufficient reason for ignoring their differences, even if they 



are slight ; for, as Wallace has pointed out, it is by the study 



of minute variations such as these, which the older systematists 



disregarded, that we may hope to obtain light on the evolution 



of species. The specimens which I have received from Co. Clare 



correspond exactly with the description already given, but I 



am able to add a few details to the same, especially in regard 



to colour. I have examined a dozen living specimens, and 



may now submit the result. 



Allolobophora Georgrii, Mich. — Length from 1^ to 2 inches, 

 breadth one-eighth to one-sixth. There are upwards of 100 segments, 

 twenty-eight of which usually precede the girdle, while seventy or more 

 follow it. The girdle covers seven or eight segments, is closely fused on 

 the back, but distinct on the under side, so that the rings can be easily 

 counted. The tubercles on the girdle are in pairs, on segments 31 and 

 33. In colour the worm is darker than is usually the case with its near- 

 est ally, A. calignosa (tiugida), and resembles some of the varieties of the 

 Green Worm (A. chlorolica). Head ruddy brown, with a lighter patch 

 where the sexual organs are situated, viz., between segments 9-12, and 

 a dirty brown behind. The girdle is lighter than the rest of the body, 

 and shews a tendency to a blue-grey. The colours are all indefinite, 

 obscure, and difficult to define. It is evident that the worm would be 

 specially adapted to poor soil. I have been able to detect the presence 

 of those peculiar bodies known as spermatophores on more than one 

 specimen, on segments 28-29 or 2 9-3°- The similarity between this worm 

 and its two nearest allies will be seen if the numerical formula repre- 

 senting the girdle and tubercle-segments of each are set forth. The 

 numerator represents the segments occupied by the tubercles or papillae 

 (itibercula pubertatis), and the denominator the girdle-segments. The 

 numbers in brackets shew the overlapping of the girdle where it is not 

 constant. 



A. turgida. A. Gcorgii. A. chlorolica. 



31 -33 31 : 33 3i : 33 '• 35 



(27) 28 - 34 (35) (28) 29 - 35 (28) 29 - 37 



There are now four earthworms known to occur in Ireland, 

 which have not been found anywhere in Great Britain. Two 

 of these (Lumbrictis papillosus, Friend, and A Hunts viacntrus, 

 Friend) are unknown at present outside the Emerald Isle. The 

 other two (A llolobophora hibemica, Friend, and A. Gcorgii, Mich..*) 

 occur in Italy or Spain, though the intermediate countries, 

 England and France, know them not. It is too early yet, 

 however, to speculate on the bearing of this fact upon the 



