1899.] ox TWO EARTHWORMS. 805 



The clitellum itself seems not to occupy quite fully the first and 

 the Jast of its three segments. 



The second characteristic feature of thifi species is the arrange- 

 ment and the numbers of the genital papillae. These papillae are 

 paired and follow the 28th segment. The greatest number of 

 pairs found in our examples was 5 ; the following numbers were 

 also observed : 4 pairs, 3 pairs ; 5 right side 4 left, 3 right 4 left, 

 4 right 3 left, 4 right 6 left. Perrier found as many as 7 pairs ; 

 Michaelsen not more than 5, as was the case with us. 



This asymmetry of the genital papillte, which is not by any 

 means a novelty any more than is the varying number of pairs in 

 individuals, is coupled with an irregularity and asymmetry of the 

 spermathecae. It is mainly upon this matter that we desire to lay 

 stress in the present communication. 



In first of all describing the species PericJueta acystis the author 

 recorded, without commenting upon the fact, that papillae were 

 also present. Now iu species without spermathecas there are, as a 

 rule, no papillae. Not many examples occur among earthworms of 

 species which are without these characteristic Oligochaetous organs ; 

 but there are a few, among them being two species of the pi-osent 

 genus. Dr. Eosa ' has described Perichceta atheea, and Dr. Michael- 

 sen ^ Perichceta harami. In the first mentioned there are no 

 genital papillte ; in two individuals of the latter the papillae were 

 reduced or absent. In species of Allolohophora, on the other hand, 

 there are no spermathecae, such as A. eiseni, there are also no 

 tubercula pubertatis. 



Of Penchatrt atheea Eosa examined several individuals, so that 

 there the coincidence of absent genital papillae and missing sper- 

 mathecas seems to be absolute. In Pericliceta biscrialis, on the 

 other baud, spermathecae are sometimes absent and sometimes 

 present. Perrier makes no mention of the matter at all in his 

 iDrief account of the species. Michaelsen had five examples, all of 

 which possessed two pairs of these organs in segments vi. and vii. ; 

 the number of genital papillae varied, as already said. 



The two specimens which formed the material upon which the 

 species Perichcpta acystis was established had each five pairs of 

 genital papillae and no spermathecas. In the present collection 

 there are 12 specimens without and G with spermathecae; but no 

 ascertainable relation exists between the condition of the papillae 

 and that of the spermathecae. We may fairly pat aside Pericha^ta 

 atheea for two reasons. In the first place, it may still be that the 

 species is, like P. hiseriuHs, sometimes with and sometimes without 

 spermathecae, and also for the reason that nn absence of genital 

 papillae is so general or at least so common among PericJueta that 

 it need have no significance in connection with the absence of 

 spermathecas. The absence, then, of any connection between 



' "I Lorabriehi racfolti a Sumatra dal dott. Elio Modigliani," Ann. Mus. 

 Civ. Genova. xxxvi. p. 520. 



^ Oligochaeten ; from Kiikenlbal, " Ergebiiisse eiiierzoologiscbea Forseljungs- 

 rpise in den Mulukken mid in Bornpo/' Abli. Senck. nat. Ge.s. sxiii. p. 20y. 



Proc. Zool. Soc. — 1899. Xo. LTI. o2 



