Fig. 1. 



PLATE 19. 



95. 4. Endoceras gemellifaritm. 



(Pag. 60.) 



1 a. External view of the fragment. 



I b. Transverse section of the smaller extremity, showing the siphuncle tube which joins the external margin ; 



within which are shown sections of the two embryo tubes. 

 1 f. Longitudinal section of the specimen, d and e being the two enclosed tubes, one of them partially covered 



with stony matter. 



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