184 MR. M. F. WOODWARD ON [Mar. 1, 



2. Description of an Abnormal Earthworm possessing 

 Seven Pairs of Ovaries. By M. F. Woodward, 

 Demonstrator of Zoology, Royal College of Science, 

 Loudon^. 



[Eeceived February 29, 1892.] 



(Plate XIII.) 



Abnormalities affecting the genitalia of the Earthworm are of un- 

 frequent occurrence, and, when such variationa occur, they, as a rule, 

 only affect accessory structures like the spermathecse and seminal 

 vesicles, not essential ones such as the genital glands. 



One or two cases have, however, been put upon record iu which 

 the genital glands were themselves affected, although these variations 

 were but slight ones. One case is described by Benhani ", in which 

 the ovary of the right side was situated on the 12th somite ; this 

 might at first sight appear to be a simple shifting forward of the 

 ovary, especially as the oviduct and the posterior termination of the 

 vas deferens of that side are also displaced ou to the segment in front 

 of that on which they are normally situated. But when compared 

 with the specimen which I now propose to describe it would appear 

 more piobable that the right ovary of Benham's specimen does 

 not correspond with the normal one, but is rather a fresh structure 

 altogether. Bergh^ has also described three abnormal specimens, 

 viz. two L. turgidus and one L.purpureus, which are of great interest 

 in having undergone an actual reduplication of the ovaries, being 

 possessed of an additional pair on segment 14, the normal ovaries 

 being present as usual ou segment 13. 



The above-cited cases are, as far as I can ascertain, the only re- 

 corded cases of variations in the position and number of the ovaries 

 in Lumhricus. 



The specimen which forms the subject of the present communi- 

 cation was a large, well-developed common Earthworm {Allolobo- 

 phora, sp. inc.), possessing a well-marked clitellum ; it was killed 

 early in November, in which month the genitalia are generally but 

 poorly developed. With the exception of the ovaries the genital 

 organs were quite normal. 



On the removal of the alimentary canal one immediately noticed a 

 number of small pear-shaped bodies (Plate XIII. fig. 1, ov.^-'') project- 

 ing backwards from the mesenteries of the segments 11-17. These 

 paired bodies are situated one on either side of the longitudinal nerve- 

 cord, and attached to the posterior face of the mesenteries by their 

 expanded bases, while their apices project back freely into the cavities 



' Communicated by Prof. G. B. Howes. 



^ " Kote ou a couple of Abnormalities," Ann. & Mag. Nat. Hist. 6th series, 

 vol. vii. (1891) p. 2.56. 



^ '• Ueb. d. Bau u. d. Entwicklg. d. Gescbleehtsorg. d. Eegenwurmer," 

 Zeitscbr. fiir vriss. Zool. 1886, vol. xliv. p. 303. 



