290 OLIGOCHAETA 



The two new species of Bourne — Pristina eqimeta and P. breviseta — do away 

 with the first and second diiFerential characters. In view of the identity in the 

 cephalization of the two genera, the remaining points of difference are, perhaps, 

 hardly of sufficient importance to warrant generic separation, particularly as only 

 one species of Naidiwtn is known, and its range of specific variation, therefore, not 

 ascertained. In both Naidium and Pristina the restriction of the pharynx to two 

 segments, and the great development of the septal glands are especially remarked 

 upon by Vejdovsky, and constitute a bond of union, which may be considered to 

 counterbalance the difierences mentioned above. 



The well-marked species belonging to this genus are only five, viz.: — 

 (i) Pristina longiseta, Eheenb., Europe and N. America. 

 (3) „ equiseta, Boukne, England. 



(3) „ breviseta, Bourne, Madras. 



(4) „ lutea, 0. ScHM., Europe. 



(5) „ proboscidea, F. E. B., S. America. 



One or two doubtful forms have also been described too incompletely for satisfactory 

 recognition ^ 



Pristina inaegualis of Eheenbeeg lias been tlius defined by bim : — 



'Setis quaternis inaequalibus, una longissima, reliquis brevissimis, pari secundo non diverso, 

 uncinis, subquinis subulatis.' 



Pristina hreviceps {= Naidium breviceps, 0. Schmidt) is tbougbt by Vejdovsky to be an 

 Enchytraeid. 



Nais temaria of Schmaeda is doubtfully transferred by Vaillant (6, p. 357) to Naidium. Tbe 

 cbief reasons for believing it to be a member of tbe genus Pristina are tbe absence of eyes, and 

 tbe commencement of botb dorsal and ventral setae upon tbe same segment. Tbe dorsal setae 

 are capillary only. The intestine is said to have a spiral arrangement. Tbe woi-m occurs in 

 Louisiana, Central America, Cuba, and Jamaica. 



(i) Pristina longiseta, Ehrenberg. 



p. longiseta, Ehrenberg, Symb. Phys. 1828. 



Pristinais longiseta, Gervais, Bull. Ac. Eoy. Belg. 1838, p. 17. 



Nais longiseta, d'Udekem, Bull. Ac. Roy. Belg. t. xxii, pt. ii. 1855, p. 553. 



Stylaria longiseta, Tauber, Ann. Dan. 1879, p. 'j^. 



Definition. Lenytk, 8 mm. ; number of segments, 20. Dorsal setae ■ of segment III much 

 longer than the other. Prostomium long. Glandular ventricle in segment VIII. 

 Five vascular arches connecting dorsal and ventral trunks. Nephridia commence in X. 

 Hah. — Europe. 



' It is possible that 'Lumlricus Mrsutus' of Dalyell (p. 140) is referable to this genus. 



