NOTES ON NORTH-AMERICAN EARTHWORMS 

 OF THE GENUS DIPLOCARDIA. 



GUSTAV EISEN, Ph.D. 



With the discovery of a species of Diplocardia possessing 

 the spermiducal pores in xx, it becomes advisable to include 

 in this genus my genus, Aleodrilns. This genus was established 

 some years ago for a species from Baja, California, Aleodrihis 

 Keyesi, and based on the position of the spermiducal pores in 

 xxi instead of in xix, as in Diplocardia communis, the only 

 species known at that time. Later finds of new species of 

 this genus show that Diplocardia verrucosa Ude stands inter- 

 mediate between the two first-mentioned species, possessing 

 the prostate pores in xx. 



The location of the spermiducal pores in Oligochaeta is gen- 

 erally considered of generic importance, and it is very rare that 

 we find variations in this respect in the same genus. But this 

 character ought to be accompanied by others in order to serve 

 as a genus characteristic, provided the distance between the 

 respective somites is not very great. If we except the absence 

 of penial setae in Aleodrihis, there are no other characters 

 which would help to sustain the genus, since we have a com- 

 plete series regarding the location of the male pores running 

 through three successive somites. As few species of Diplo- 

 cardia are known, and no confusion will ensue, a fusion of 

 the two genera Aleodrihis and Diplocardia will help to simplify 

 the already extensive nomenclature of the terrestrial Oligo- 

 chaeta. Through the kindness of Prof. Frank Smith, I have 

 had opportunity to examine all the various Diplocardia species 

 at his disposal, and am able to add a few observations on minor 

 points. I have also received several new species from North 

 Carolina, which I describe here preliminarily, reserving a more 

 detailed description for an illustrated paper now in press. As 

 many more species of Diplocardia are likely to be found in 

 the United States, a review of the species, so far known, is of 



