72 ox XUDIBRAXCHS FROM ZAxVZIBAR. [May 6, 



■v-hich have a dorsal aims and a miiltiseiiate radula. As a family 

 the Janidse are charactei'ized by the presence of hepatic diverticula 

 and of cerata in the antei'ior portion of the dorsal suiface, in 

 front of the rhinophores. Another character peculiar to the 

 family, but not universal in it, is the crest between the rhino- 

 phores. Thei-e ai'e four well-marked genei'a : — Madrella, with 

 lateral anus, trisei'iate radula, papillous rhinophoi'es, a rudimen- 

 tary crest, and jaws without teeth. The other three genera have 

 the additional peculiarities of a dorsal anus and a multiseriate 

 radula. Proctonotus has simple rhinophores, no crest, and jaws 

 without denticles. Janolus has perfoliate mandibles and very 

 large jaws without denticles ; the foot is also exceptionally bi'oad. 

 Janus has perfoliate rhinophores, a toothed mandible, and a ci'est. 



EXPLANATION OF THE PLATES. 



Plate V. 



Figs. 1, 2. CrossJandia viridis, p. 64. 



3. „ „ var. (?)/?(sea. 



4. „ „ outer teeth of two consecutive rows of the radula. 



5. „ „ rhiuophore cup, one side removed. 



6. „ „ central and inner teeth of radula. 



7. „ „ jaws, from in front. 



8. „ „ jaws, from the side. 



Plate VI. 



Fig. 9. Zatteria broivni, p. 62. 



10. „ „ diagrammatic view showing position of cerata. 



11. „ „ one of the cerata. 



12. „ „ tooth of radula. 



13. „ ,, view of head from belovv'. 



14, 15. Madrella femiginosa, p. 71, dorsal and ventral view. 

 16. „ „ one row of radula — a, median ; h, h, lateral 



teeth. 



[12] 



