Anatomy of Notoryctes typhlops. 109 



{/■d.) opens into the ventral nasal furrow {v.ii.f.), in the same 

 plane as the ventral opening of the naso-palatine canal {ii.p.d.) 

 into the buccal cavity. The outer bar of Jacobson's cartilage 

 {o./.c.) is here seen separated from the vertical part of the 

 enclosing cartilage, and anterior to its union with the ventral 

 outer edge of Jacobson's cartilage, arching in this section over 

 Jacobson's duct. The gi'eat development of mucous glands is 

 also evident hei'e. Zeiss A,* oc. 2. 



Figure 4. 



Portion of transverse vertical section, three posterior to Fig. 7, 

 showing connection of outer bar of Jacobson's cartilage {o./.c.) 

 with ventral outer edge of the now crescentic Jacobson's cartil- 

 age {/.c). The opening of the naso-palatine canal {71. p. d.) from 

 the ventral nasal furrow {v.n.f.) is clearly shown, as also the 

 rudimentary cartilages of the nasal floor {ii.f.c). The naso- 

 lachrymal duct is seen lying in a definite canal in tlie alveolar 

 bone, below tlie maxillo-turbinal process. Zeiss A,* oc. 4. 



FlGURK 5. 



Section similar to last, but a little posterior to it, showing 

 Jacobson's cartilage {o./.c.) diminishing on the left, and quite re- 

 placed by a bony shelf {p-P.s.) from the palatine processes of the 

 jiremaxillary bones {p.p.p.) on the right. Zeiss A,* oc. 4. 



Figure 6. 



Ti-ansverse vertical section through Jacobson's Organ {/O.), 

 showing more minutely its structure and relations. The differ- 

 ence between the lateral {Lw.) and medial walls {m.zv.) may be 

 noted, as also the artery [a) and vein (v) in the lateral wall, and 

 the cavernous tissue (c.t. and v.) in the ventral part of the medial 

 wall. The bundle of nerve fibres is seen descending, to be dis- 

 tributed to the medial wall from the main Jacobson's branch 

 {n.f.) of the olfactory nerve. The mucous glands {ni.g.) of the 

 mucous membrane may be contrasted, in appearance and struc- 

 ture, with those Ijelow, which have much smaller alveoli. The 

 bony slielf {p-p.s.) from the palatine processes is clearly seen. 

 Zeiss A., oc. 4. 



