130 Mr. F. A. Bather on a 



tlipir npices or free ends. If Protoscolex was setiferouf, it 

 follows that the setai were disposed as in the PeiichiBtidae, 

 and this is what one woiihl expect. The double rows ot" 

 ])apTllje nijiy be compared with the secondary annulation 

 (ccasi'nally found in modern forms, and so present no 

 difficulty. 



It may be oljocted that the Oligochieta, especially the 

 group to which the Peiichaetidae belong, are normally 

 terrestri.il oi, ;it most, inhabitants of fresh water. There is, 

 liowever, h priori reason to su])pose that terrestrial oligo- 

 chsetes weie derived from aquatic, and ultimately marine, 

 forms. Tiie primitive Pltreorycles lives both in water and on 

 land. It is among the Microdrili, with less pronounced 

 cliicllum, that most aquatic species are found. Thus, some of 

 the Tiiljificidaj (e. g., Ctitelio and Venniculiis) and various 

 Enchytrreids are marine or littoial. Among the Megadrili 

 there are, at any ratc^, three marine genera — Poiitodrilas, 

 Acanthodrilus^ and Pontoscoled'. 



The rarity of Oiigochseta among fossils may be explained 

 as due to their softness and easy decomposition. The hypo- 

 thetical piimitive forms of marine iiabitat would probably 

 have been less easily preserved than the familiar eaithworni. 

 The palaeontologist has to rely on an occarsional lucky chance, 

 such as the blow that tor the first time exposed a P rotoscolex 

 in the long-ex])loited beds of the Lower Ludlow formation. 

 So soon as the Oligochteta took, to fresh waters, swamps, ami 

 the land, their oj)portunities of leaving an imperishable record 

 were further restricted. 



The only fossils that anyone has hitherto proposed to refer 

 to the Oligochffita are "fiinf bmune Abdriicke, welche hochst 

 wahrscheiidich den liiniielwuiiuern anuehoren," tbund in the 

 JSoeciytruthia beds of the Coal Measures near Jiakouitz, 

 Bohemia, and described as Proiiuiilites carl;onarius by 

 J. Kusta (1888, Sitz.-ber. bohmisch. Gesell. \Vissensch., 

 JMath.-nat. CI., Jahrg. 1887, p. 5(J1, pi. fig. 1). The length 

 is a little over 10 cm., diameter 0'5 mm. to at most 2 mm., seg- 

 ments (in the holotype, whicii is 1*0 mm. wide) about 0*6 mm. 

 high. All specimens are bent, cuived, or even twisted. The 

 side-contours are not veiy sliarj). Towaids one end of the 

 liolotype a canal runs down the midille of the body ; its 

 width IS not stated, and it does not appear in the figure. 



In all the given details Prcuaii/ites agrees with Prolo- 

 sculex, and the measnren)ents of the segnunts are the same 

 as in Protoscolex aiinylex. Papillie are not mentioned, but 

 jieither are they recorded for I'rvtosa-lex sitiipltj', J\ lentiis^ or 

 the genotype I', covmytonensis. The reference of Pronutdttes 

 carionarius to Protoscolex is therefore inevitable. 



