258 Messrs. J. Wood-Mason and A. Alcock on 



asymmetrical and abnormal positions of the genital pores in 



Allurus, sp. 



For the present I content myself Avith merely noting without 



comment these interesting abnormalities. 



EXPLANATION OF PLATE III. 

 Astacus Jluviatilis. 



Fig. 1. View of ventral surface of alDnormal specimen of female crayfish, 

 sufficient to show the position of the second genital aperture 

 {o.p. 2) on each side, o.p. 1 being the normal oviducal pore ; 

 X., XL, XII., XIII., indicate the last four ambulatory limbs, 

 which are represented as cut short ; Ab. 1 the first abdominal 

 sternum with normal female appendages. 



Fi(j. 2. Side view of the same crayfish partially dissected; the hinder part 

 of the carapace {cci) has been removed, the epimeron (ep) and gills 

 have been cut away ; the bases of the ambulatory appendages 

 (10, 11, 12, 13) are represented ; o is the normal ovary, o.d. 1 the 

 normal oviduct, o.d. 2 the accessory oviduct passing into appen- 

 dage 13 ; Li., liver, underlying ovary ; Ab. 1, Ab. 2, the first and 

 second abdominal segments. 



Lumbricus hereuleus. 



Fii/. 3. Ventral view of segments XII. to XVI., showing on the animal's left 

 side the normal oviducal pore ( 2 ) and spermiducal pore ( (5 ), 

 and on the right side the abnormal position of these apertures. 



Fiff. 4. Dissection of segments IX. to XIII., to show the asymmetrical con- 

 dition of internal structures. The normal condition obtains on 

 the left side, the abnormal on the right ; spth.^, spthi^, the 

 spermathecae ; ov., abnormally placed ovary ; eal., calciferous 

 gland ; oes., oesophagus. None of the structures have been cut 

 or removed, the calciferous gland and sperm-sac of segment XII. 

 being absent. 



XXVII. — Natural History Notes from H.M. Indian Marine 

 Survey Steamer ' Investigator .^^ Commander It. F. Iloshynj 

 R.N.J commanding. — No. 21. Note on the Results of the 

 last Season's Deep-sea Dredging. By J. Wood-Mason, 

 Superintendent of the Indian Museum, and Professor of 

 Coni])arative Anatomy in the Medical College of Bengal, 

 and A. Alcock, M.B., Surgeon I. M. S., Surgeon-Natu- 

 ralist to the Survey. 



[Concluded from p. 202.] 



Family InacMdae. 



Plattmaia, Miers. 



35. Platymaia Wyville-Thomscni, Miers. 



Platymaia Wyville-Thomsoni, Miers,' Challenger' Brachyura, 1886, 

 p. 13, pi. ii. tig. 1. 



Three specimens (one male and two ovigcrous females), 

 from Station 56, 240 to 220 fathoms. 

 The male measures : — 



