Marsenia dubia, n. sp. 



Figure 1. — The head, from above, with tentacles and ophthalmophoria. Cam. luc. x 100 diam. 



„ 2. — The superior intestinal mass, after removal of the shell ; a, the true stomach ; b, the hermaphrodite 



gland ; c, the foliated gland ; d, the pericardium, at its right side the kidney ;* e, the olfactory 



organ, behind it the gill ; the muscular facettes very distinct to the right and left ; at the 



anterior margin the shell-fillet. 

 ,, 3. — a, the penis ; b, protruded end of the vas deferens. Cam. luc. x 100 diam. ■ 

 „ 4. — A median plate of the radula, from below. Cam. luc. x 350 diam. 

 ,, 5. — Part of the radula, from above ; a, median plate ; b, b, lateral plates ; c, fillet of the radula. Cam. 



luc. x 750 diam. 

 „ 6. —Lateral plate, from the under side. Cam. luc. x 750 diam. 



Marseniopsis pacifica, n. sp. 



Figure 7. — The shell, from the right side, x 2. 



„ 8. — The superior intestinal mass after removal of the shell, x 2 ; a, ovary ; b, foliated gland; c, right 



muscular facette, and above this the mucus gland ; d, space between foliated gland and e, gill. 

 „ 9. — Head, from the under side, with tentacles and ophthalmophoria. 

 „ 10. — Central nervous system, from above; a, cerebral ganglia; b, b, pleural ganglia; c, infra-intestinal 



ganglion ; d, supra-intestinal ganglion ; e, buccal ganglia. 

 „ 11. — Pedal ganglia ; a, accessory pedal ganglia ; b, b, cerebro-pedal and pleuro-pedal connectives; e, c, 



otocysts. 

 „ 12. — The bulbus pharyngeus, from the side; a, mouth tube; b, cartilaginous patch; c, Musculus lateralis 



inferior ; d, radula-sheet ; e, oesophagus. 

 „ 13. — a, anterior margin of the labial-disc; 6, b, mandibular plates. 

 „ 14. — Anterior part of a mandibular plate ; a, anterior end. Cam. luc. x 350 diam. 

 „ 15. — Cuticula of the external mouth. Cam. luc. x 350 diam. 

 „ 16. — Part of radula, with three series of plates, from above. Cam. luc. x 350 diam. a, median plates; 



b, b, lateral plates ; c, external hooks ; d, d, fillet of the radula. 

 „ 17. — Two median plates. Cam. luc. x 350 diam. 

 ,, 18. — Two other median plates. Cam. luc. x 350 diam. 

 „ 19. — a, lateral plate; b, innermost external hook. Cam. luc. x 350 diam. 

 ,, 20. — a, median plates ; b, lateral plates, from the under side. Cam. luc. x 350 diam. 

 „ 21. — a, innermost; b, outermost of the two external hooks; c, fillet of the radula. Cam. luc. x 350 



diam. 

 ,, 22. — a, oesophagus ; b, wider part of the same ; c, foliated (glandular) stomach ; d, gut ascending to the 



true stomach. 

 ,, 23. — Branchial leaf; a, anterior margin. Cam. luc. x 55 diam. 

 ,, 24. — Renal organ, from the under side; a, pericardio-renal aperture. 

 „ 25. — Part of the foliated gland. 



,, 26. — a, mucus- and albumen-gland; b, seminal vesicles. 

 „ 27. — a, vagina ; b, vulva ; c, vestibular sac. 



Marseniopsis murrayi, r>. sp. 



Figure 28. — Transverse section of a whole mandibular plate ; a, posterior part ; b, anterior part. 



„ 29.— Median plate, from the side. Cam. luc. x 350 diam. 



„ 30. — Median plate, from above. Cam. luc. x 350 diam. 



,, 31. — Lateral plate, obliquely from the under side. Cam. luc. x 350 diam. 



„ 32. — Lateral plate, from the side. Cam. luc. x 350 diam. 



,, 33.— a, lateral plate ; b, external hooks. Cam. luc. x 350 diam. 



,, 34. — Lobe of the testis; a, efferent duct. 

 Figures 35, 36. — Zoosperms. 

 Figure 37. — A number of Zoosperms (T) from the testis. 



„ 38. — Penis ; a, base ; b, opening of the vas deferens. 



* The letter e, indicating the olfactory organ, has been omitted in the plate. 



