The Ea rth ivorms of I re I a nd. 275 



Dr. Gustaf Eisen published a paper on New England and Canadian 

 Worms, in which he described, among others, a diminutive species from 

 Niagara, which he regarded as the type of a new genus. This genus he 

 named Tetragouiirus, and supplied the following diagnosis : — 



"Body cylindrical in front, quadrangular behind. Male pores on seg- 

 ment II [ = the 12th segment according to our English mode of reckon- 

 ing], setae in approximate pairs. Lip or prostomium not dividing the 

 first ring or peristomium. It comes nearest to the genus Alliirus, from 

 which it is distinguished, however, by the position of the male pore, 

 which in Alliirtis is on segment 12 [= 13 in English], but in Tetragomirus 

 on II [= 12], as well as by the lip failing to cut the buccal segment or 

 peristomium." 



Eisen next supplies details of the species {Tetragonurus pupa) : " Lip or 

 prostomium small, acuminate in front, pallid, not dividing the peristo- 

 mium. Male pores small but conspicuous. The girdle prominent, 

 usually composed of five segments, viz., 17-21 [= 18-22]. Tubercula puber- 

 tatis conspicuous, three on each side of the girdle, occupying the iSth, 

 19th, and 20th segments [= 19, 20, 21]. About 40 segments in all; length 

 about 25 mm." 



Some Swedish comments on the foregoing description, which is 

 written in Latin, inform us that the puberty band {tubercula pubertatis) 

 exists on each side of the girdle in the form of a wart-like protuberance 

 or keel, extending in a continuous line over three consecutive segments. 

 The girdle is well-marked and may be readily distinguished from the other 

 portions of the bod5^ It stretches over five segments, one of which is 

 before and one behind the tubercula. The general colour is sienna-brown, 

 and the worm when alive closely resembles Alhinis both in general form 

 and in the nature of its habitat. 



Thus far I have failed to find any confirmation of Eisen's discovery, 

 and most recent writers drop the genus out of consideration. May not 

 the worm I am about to describe prove to be the identical creature } The 

 Bangor worm is about an inch and a-half long, and has the girdle and 

 tubecula exactly in the position described by Eisen. The girdle is more- 

 over, prominent, and the colour is sienna-brown in front, with a dull 

 yellow-brown tail. The male pores, however, are placed exactly as in 

 Allurus on segment 13, and thus prevent us from assigning the worm to 

 the genus Tetragonurus. 



The question now remains : did Eisen make a mistake respecting the 

 position of the male pore .? I dare not insinuate so much, since, next to 

 Rosa, he is the most accurate and painstaking foreign investigator whose 

 works I have consulted. For the present therefore we must assume that 

 there are two worms which are practically identical in every important 

 point, except the position of the male pores. If this is a fact it must 

 have a meaning, and it will be of interest to observe w^hat light future 

 research may be able to throw upon the question. 



I have, during the past few years collected and examined many thou- 

 sands of Allurus, and have invariably found them living either actually 

 under water, or in close proximity to it. Bearing on this point I may 



