Ahnorvud Oviducts in Homarus vulgaris. 3 



snpernumeraiy vasa deferentia of Nephrops were connected 

 witli the testes, but Marshall * states that in some of the 

 abnormal males examined by him the apertures opened in- 

 ternally into blind sacs, in others the connection, partial or 

 complete, between the testis and the supernumerary aperture 

 was by means of a branch of the normal vas deferens be- 

 longing to the last thoracic somite. 



As regards the European crayfislies of the genus Astacus, 

 the gonad is sometimes hermaphrodite f, and females are 

 known sometimes to bear on the first abdominal somite large 

 appendages like those of the male instead of the usual 

 vestigial structures J. Desmarest § records a female Astacus 

 with supernumerary orifices on the fourth or penultimate 

 legs, and oviducts which on each side forked downward so as 

 to become connected with the apertures on both third and 

 fourth legs. A somewhat similar case is given by Benham ||, 

 only in this animal there were on each side two oviducts, 

 opening on the third and fifth legs. Bateson T| mentions 

 twenty cases of female crayfishes having a unilateral super- 

 numerary of)ening on one of the fourth legs; he also cites 

 one case with additional oviducal openings on both of the 

 fourth legs, one case with extra openings on both fourth and 

 filth legs, and eight cases in whicli the oviduct was suppressed 

 on one side, so that the animal had but one oviduct in all. 

 Abnormalities in the males are much less common than in 

 females, for Bateson found ordy one abnormal male in 714; 

 this one departed from the normal in the suppression of the 

 lower part of the vas deferens, and its external opening, on 

 one side of the body. In most of the twenty feuiales with 

 an additional oviducal aperture on one of the fourth legs, the 

 oviduct on the abnormal side of the body was in the form of 

 an inverted Y, as in Desmaresi's case. 



In Parastacus hasderi'^^j a South American speciesof cray- 



* L. c. p. 8. 



t See V. la Valette St. George, Arch. f. mikr. Anat. xxxix. 1892, 

 pp. 504-521. 



t Bergenrlal, D., Bihang k. Sv. Vet.-Akad. Handlingar, Stockholm, 

 xiv. iv. 3, 1888, pp. 85 ; and xv. iv. 5, 1889, pp. 15. 



§ Desmarest, E., Ann. Soc. Entomol. France, s6i\ 2, vi. 1818, pp. 479- 

 481. 



II Eenham, W. B., Ann. & Mag. Nat. Hist. ser. 6, vii. 1891, p. 256. 



^ Bateson, W., Materials for the Study of Variation (London, 1891), 

 p. 153. 



** Lonnberg, E., Zool. Anzeiger, xxi. 1898, pp. 331-335 and pp. 315- 

 352. For other observations on su pern uaieraiy genital orifices in Paras- 

 tacus see von Martens, E., Sitz.-Ber. Ges. naturf. Fr. Berlin, 1870, p. 3 ; 

 von Ihering, II., Congres International de Zoologie a Moscou, 1892, 

 part ii. (1893) pp. 43-49 ; and Faxon, W., Proc. U.S. Nat. Mas. xx. 

 (Washington, 1898), pp. 61.']-(;91 (see particularly pi. 70. tig. 3). 



1* 



