Couple of Abnormalities. 257 



(" nepliiidia ") in each segment ; most are suppressed in the 

 Crustacea, tliough those of the second antennarj segment and 

 of the second maxiUary segment remain, and with the genital 

 ducts in the 11th and 13th (and 12th in abnormal forms) help 

 to fill up the series. 



It is of course for such suggestions as these that the present 

 abnormality is worthy of record. 



The second case is that of a common earthworm — Lumhri- 

 cus herculeus, Savigny {=:L. agricola^ HofFmeister) . I have 

 examined some thousands of specimens of this species for 

 class-work and other purposes, but this is the only case of an 

 asymmetrical co\\(Wi\o\\ that has come under my notice*. Ex- 

 ternally the asymmetry affects the male and female apertures 

 (see fig. 3) ; both these are normally placed on the animal's 

 left side, i. e. the oviduct opens on the 14th segment, the 

 sperm-duct on the 15th. On the right side, however, each 

 of these pores is one segment in front, viz. on the 13th and 

 14th segments. 



The clitellum is normal and symmetrical. 



Of the internal organs (fig. 4) both genital system and 

 alimentary system present asymmetry in certain segments. 

 The organs of the left side are normally placed and fully 

 developed ; but on the right there is only one spermatheca^ 

 lying in segment ix. ; and instead of the usual three sperm- 

 sacs only those in segments ix. and xi. are present ; that of the 

 twelfth segment is absent. The ovary of this side is in segment 

 xii. instead of in xiii. The testes and funnels are normal on 

 both sides. 



Of the alimentary system the calciferous glands are affected 

 on the right side, that of segment xii. being absent. 



With regard to abnormalities in earthworms, Beddard has 

 recorded a large number of cases for Perionyx excavatus] ^ and 

 has recently noted a case, e. g. Perichceta Fo7-besi\, in which 

 the spermathecas are asymmetrically developed (and this in 

 each of the two specimens in his possession), there being 

 two on one side and one on the other, in the same seg- 

 ment ; I have already noted a similar condition in Microchoita 

 liappi §. 



Michaelsen ||, in a just-publislied paper, records certain 



* A second similar example came under my observation -while this note 

 was in the press. 



t Proe. Zool. See. 1886, p. 308. 



i Pfoc. Zool. Soc. 18'J0, p. Co. 



§ Quart. JoLirn. Micr. Sci. xxvi. 



II Jahrb. d. Hamburg. Wiss. Anat. viii. 



