PEARLY NAUTILUS. 



347 



Fig. 4. — Diagrams of tlie male and female generative organs of the Pearly 

 Nautilus, to show the relation of the rudimentary duct of the left side to 

 the testis and ovary respectively, and of the cardiac ventricle to the 

 organs of both sides. Drawn by Mr. A. G. Bourne. T. Testis. 

 0. Ovary. Ac. Accessory gland of the male apparatus. Jlh. Albumini- 

 parous gland of the female apparatus. A^". Needham's sac in the male, 

 in which the spermatophorcs arc formed. P. Penis (in tiie male). 

 R. G. 0. Right genital orifice. L. G. 0. Left genital orifice, Pijr. Owen's 

 pyriform appendage, attached by membrane to F., the cardiac ventricle 

 with its four branchial veins, and also to the testis or the ovary. Fo. 

 Foramen in the membrane, which attaches the pyriform appendage to 

 the ventricle and to the testis or ovary. The foramen places two portions 

 of the viscero-pericardial sac in free communication with one another. 



