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JOURNAL OP CONCHOLOGY, VOL. I3, NO. 4, OCTOBER, 191O. 



to 'sucker,' and become distended into spherical masses of 14 mm. 

 diameter, the 'suckers' being apparently used as fulcra and hold- 

 fasts, while the spermatophore and epipliallus of each is projected 

 into the spermatheca of the other. They remain thus coupled 

 from 15 minutes to half an hour (Fig. 2). 



Fig. 2 (nat. size). — .4. ater in cop. viewed from above. 



I have been greatly helped in my dissections by the excellent 

 figures in Mr. J. W. Taylor's "Monograph"; and it is due to the 

 kindness of Mr. J. C. Melvill that I am enabled to reproduce the 

 figure from Ferussac's work. 



Fig. 3 (enlarged). — Evaginated upper atrium separated from another in the act of coupling 

 1, epiphallus and spermatophore ; 2, duct from spermatheca; 3, the 'sucker.' 



Fig. 4 (enlarged). — Showing upper atrium, dissected open, exposing — r, epiphallus; 2, en- 

 trance of duct from spermatheca; 3, the 'sucker' with corrugated surface. 



