go CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



harmonize all the conflicting statements and descriptions, 

 and has expressed the opinion that all refer to one single 

 species, which must then be known as Pontoscolex core- 

 thrurus (Fr. Miiller). Horst and Beddard, who are the only 

 other investigators of this species, readily coincided with 

 the views expressed by Rosa; and Beddard, in his large 

 monograph on the Oligochseta, has joined the variously 

 described species, UrochcBta hystrix, U. duhia and Ponto- 

 scolex corethriirus, under the one head, P. corethriirus. I 

 do not concur with them in this arrangement, as my speci- 

 mens differ from those described by Beddard in at least one 

 very important point, namely, the location of the spermathe- 

 cal pores. Beddard distinctly states (45) that " the aper- 

 ture is in each case placed quite close to the anterior margin 

 of the segment." In another place he states that the sperm- 

 athacae are in segments VII, VIII and IX. It can only 

 be understood from this that the pores are situated in the 

 anterior parts of VII, VIII and IX, and near to the anterior 

 margin of the respective segments. In my specimens from 

 Mexico, the pores of the spermathec^ are preseptal, that 

 is, they are situated in the posterior part of the somites, 

 which character I think is of sufficient importance to be of 

 specific value. If, after re-examination, the postseptal posi- 

 tion of the spermathecas in the species examined by Bed- 

 dard, Rosa, and Horst proves to be constant, then there 

 will remain no doubt as to the specific difference of my 

 Mexican specimens. 



A re -examination of the various specimens described as 

 Pontoscolex corethruriis is, therefore, highly desirable, and 

 until this is made the question of the distribution of Ponto- 

 scolex cannot be finally settled. There is every reason to 

 believe that several additional species of Pontoscolex will 

 soon be found. In his monograph on the Oligochasta, Bed- 

 dard recognizes the following species: P. corethriirus (Fr. 

 Miiller), P. arenicola Schmarda and P. hawaiiensis Bed- 

 dard. To this number has recently been added another, 

 P. Lilljehorgii (Eisen 19). The fact that we possess 

 four distinct species of Pontoscolex argues very strongly 



