HARDWICKE'S SCIENCE-GOSSIP. 



8i 



Lucanus sang. Nine years later Duges wrote again 

 on worms in the same periodical, but put his worm 

 by the side of Savigny's, and spoke of them as distinct 

 species. He now calls them Lumbricus, and says of 

 Ihe first (Z. tctracdrus) that the clitellum is composed 

 of seven segments ending with the 28th, and the 

 worm is small and fragile, frequenting the neighbour- 

 hood of stagnant waters, and crawling out at night in 

 their vicinity. Of his own species (Z. ainphishicna) 

 Zic says that there are six segments to the clitellum, 

 which again ends on the 28th, and the habitat is the 

 same. It differs, however, from the other not only 

 in the number of segments which go to form the 

 girdle or clitellum, but also in its smaller size, the 

 prismatic and crenelated form of the tail, and the 

 semi-lunar shape of the lip or prostomium, which in 

 one case (Z. tetraedrus) is only slightly angled on the 

 side of the following segment, whereas the lip of the 

 ■other species cuts the segment completely. The 

 colour of the one (Z. tctracdrus) is a dull brown, 

 whereas it is violet in the other, and has a tendency 

 to iridescence. These distinctions appear to have 

 iieen overlooked to a large extent by later writers. 



Fig. 58.— Seta (with five muscular attachment?, a) and 

 spinets. 



In 1843 lloffmeister gave the worm a new name 

 (Z. agilis), calling it the agile worm, which is very 

 accurate, but not so characteristic as the names already 

 given by Savigny and Duges, as there are others 

 quite as active. Though it still continued to attract 

 attention, no alteration was made in the terminology 

 till 1870, when Eisen first recognised it as a distinct 

 genus, and called it Allurus, not merely on account 

 of its shape, but because the male pore, or vulva as it 

 was formerly called, is found on the thirteenth instead 

 of on the fifteenth segment as in Lumbricus. Eisen 

 has also recognised the existence of certain well- 

 marked differences among the various specimens 

 which he has examined, and he has named two or 

 three varieties. I believe that in some instances 

 specific rank will be ultimately accorded to some of 

 1 he varieties, a point to be discussed in our next section. 

 Since Eisen's day Allurus has been still further 

 studied by Rosa, Beddard, and others, and I have 

 been able from my own researches to confirm and 

 amplify their accounts of this curious worm. The 

 following table will present the historical data in a 



compact form, and enable the student readily to turn 

 to the earlier monographs and works where the 

 subject is discussed. 



1S28. Entcrion tctraedruvi, Savigny (Cuvier, 

 " Histoire des Progres des Sciences natur- 

 elles." Ser. ii., vol. iv., p. 17, or vol. ii. 

 No. 20, p. III). 



182S. Entcrioji Amphisbaeiia, Duges ("Annales 

 des Sciences naturelles." Ser. i., vol. xv., 

 p. 293, Plate 9, fig. 19, 20, 24). 



1S37. L^imbriciis tetraedrus, and Liunbricus anip/iis- 

 baena, Duges ("Ann. des Sc. nat.," Ser. 

 ii., vol. viii., pp. 17, 23). 



1S43. Lumbricus agilis, lloffmeister (Wiegmann, 

 "Archiv fiir Naturgeschichte," p. 191, 

 tab. ix. fig. 6; " Familie der Regen- 

 wiirmer," 1845, p. 36). 



1870. Allurus tctracdrus, Eisen ("Ofv. af Kongl. 

 Vetensk. Akad. Forh.," p. 966 ; ibid. 

 1873, No. 8, p. 54). 



Other references will be given under the next 

 section. 



II. DESCRIPTION OF ALLURUS. 



It will be well, before I enter upon a detailed 

 description of the square-tailed worm, to explain one 

 or two of the technical terms in common use in this 

 branch of science. The extreme anterior or fore-part 

 of the worm's body is called the prostomium, because 

 it is before and above the mouth (stoma). It is 

 sometimes spoken of, less technically, as the lip. On 

 either side of the body, usually about midway between 

 the lip and the swollen portion, one finds either a 

 protuberance or a depression. Here the male pore is 

 situated, sometimes on papillae, at other times sunk 

 below the surface of the epidermis, and detected with 

 difficulty. Its position and appearance, like the shape 

 of the prostomium, is of great help in the identification 

 of species. The swollen portion in an adult worm is 

 called the clitellum, it is also popularly known as the 

 girdle, while cingulum is the term in favour with 

 some authors. Along the back there exist a number 

 of minute apertures connected with the co;lom which 

 are known as the dorsal pores, while there exist 

 under or near the clitellum in certain species other 

 pores called ' tubercula pubertatis.' Internally we 

 find numerous glands and organs whose functions can 

 only be understood by those who have read some 

 account of the anatomy and physiology of the worm. 

 If we take the external characters first, we shall 

 find that Allurus ranges from one to two inches in 

 length, but is capable of stretching to nearly three 

 inches when hastening away from its pursuer. It 

 varies greatly in colour, as we have already seen, 

 from a beautiful rich yellow to dull brown, and from 

 a light brown to violet with iridescence. It has a 

 square-tail, containing usually about forty segments, 

 making the total number of sediments for the whole 



