DESCRIPTIONS OF GENERA AND SPECIES 221 



(2) Claparedilla lankesteri, VEJDOVSKY. 



C. lankesteri, VEJDOVSKY, Syst. u. Morph., 1884, p. 54. 

 Lumbriculus lankesteri, VEJDOVSKY, SB. Bohm. Ges. 1883, p. 226. 



Definition. Prostomium double as long a* the luccal segment ; first Jive segments bi-annulate ; 

 loth pain of perivisceral arches with pennate series of caeca. Ilau. Podebrad, 

 Bohemia. 



As this species is only known by a single immature example, it cannot be regarded 

 as absolutely certain that it should be included in the same genus as the last ; the 

 difference in the arrangement of the contractile caeca of the perivisceral vessels is 

 made use of in the definition of the species. It will be noticed that the arrangement 

 which characterizes the present species is more like that of the last species as 

 described by VEJDOVSKY. 



Genus STYLODRILTJS, CLAPABEDE. 



DEFINITION. Setae bifid ; clitellum, X-XII ; spermathecae, a pair in IX ; a pair 

 of non-retractile penes present on segment X, perforated by sperm-ducts ; 

 spermiducal gland pear-shaped, with, long duct. 



This genus has been anatomically described by CLAPAREDE (2) and by VEJDOVSKY 

 (24) ; more recently, BENHAM (9) has described a new species of which he has 

 detailed the structure. A few details upon Stylodrilus have also been contributed 

 by RATZEL (3). 



The vascular system consists of the usual dorsal and ventral vessels put into 

 communication in each segment by two pairs of vessels, both of which, as well as, of 

 course, the dorsal vessel, are contractile ; one of the communicating vessels is called by 

 CLAPAEEDE the ' anse intestinale.' the other ' anse pe'rivisce'rale.' The former lies 

 anteriorly in the segment, instead of posteriorly, as in Claparedilla; it is imbedded 

 in the peritoneal cells which cover the intestine, but is nevertheless easy to see on 

 account of its large size ; neither of the trunks shows any caecal appendages, such 

 as exist in other Lumbriculidae. 



The nephridia are wanting in the first six segments. They exist in the seventh 

 and from the thirteenth onwards. The external pore is in front of the ventral setae. 



The most remarkable feature about the reproductive organs is the existence of 

 a pair of penes which are non-retractile, but are perforated by the sperm-duct ; 

 they exist in all three species of the genus, and lie behind the ventral setae ; the 



