PERICHAETA SIEBOLDI, 241 



single specimen, exactly presenting the above named cha- 

 racters. Ou the contrary they observed several individuals 

 in which the spermathecae lie one segment more anteriorly, 

 therefore opening in the groove between segments V/VI, 

 VI/VII, VII/VIII, and iu which the number of setae in 

 the sperraathecal region only amounts to 60. Because these 

 worms not only have a very wide distribution in Japan, 

 but are also found in the same locality where the speci- 

 mens of the European authors have been collected, they 

 regard them as belonging to P. Sieholdi, though they hesi- 

 tate to suppose that all the specimens in Europe should 

 present the same variation, or that there should have been 

 made a mistake in stating the situation of the sperma- 

 thecae. It is much to regret, that Goto and Hatai say 

 nothing about the other characters of their worms, and 

 only mention the number of setae lying between the male 

 pores, being 14 — 19; for P. Sieboldi shows the remar- 

 kable feature, that instead of the single intestinal coecura 

 of most other PmcAaeto-species, there are six or seven of 

 these diverticula, separated in two groups, of which the 

 superior one is the longest. Moreover, both Rosa and I myself 

 found the spermathecae provided with a zigzag diverticulum 

 and the large prostata divided in three lobes, two larger 

 crescentic ones and a smaller, pear-shaped one in the 

 middle. After a re-examination of the type-specimen, by 

 which were confirmed all my observations, made fifteen years 

 ago, and considering that the observed differences can 

 hardly be ascribed to variation, I cannot believe, that the 

 worms examined by the Japanese authors belong to our 

 P. Sieboldi^ but I venture to suggest that they must be 

 identified with a nearly allied species P. Ijimae '), also 

 from Japan and circumstantially described by Rosa. In 

 this species, that appears to be half as long as P. Sieboldi, 

 the spermathecae lie one segment more anteriorly and the 



1) Loc. cit. p. 402. 



Notes from the Ley den Musetina., Vol. JtX. 



16* 



