1891.] ON THE ANATOMY OF ORNITHORHYNCHUS. 576 



et inter se distinctius separatis, pedibus sex posticis aurantiis, haud 

 luteis ; ab O. amazonico, E. Sim., preesertim differt ceplialothorace 

 longiore et humiliore. Ab 0. walckenaeri, M'Leay (sp. quse mihi est 

 ignota), verisimiliter distinctus est. 



EXPLANATION OF PLATE XLII. 



Fig. 1. Bysderina princi^xdis, p. 557. Lateral view of palp, of c? . 

 2. Bysderina spinigera, p. 558. Leg. 

 3. . Palp, of S > lateral view. 



4. Pelicinus marmoratios, p. 559. Lateral view of palp, of (^. 



5. Opopcea deserticola, p. 560. Lateral view of palp, of (S • 



6. Oonops sinnimanus, p. 563. Lateral view of leg. 



7. Oonops globimanus, p. 563. Lateral view of palp, of c5" • 



8. Oonops pulicarius, p. 564. Lateral view of palp, of (S . 



9. Oonops figuratus, p. 564. Abdomen from above. 



10. Ochyrocera arietina, p. 566. Lateral view of palp, of (S . 



11. Ochyrocera guinquevittata, p. 566. Lateral view of palp, of cJ. 



12. Theoclia radiata, p. 567. Lateral view of palp, of (^ . 



13. Scytodes longipes, p. 567. Lateral view of palp, of cS. 



14. Scyiodes hebraica, p. 668. Cephalothorax from above. 



15. Scytodes bajula, p. 569. Lateral view of palp, of S • 



16. 17. Scytodes linearipes, p. 570. Cephalothorax from above. 

 18. Nops coccineus, p. 572. Lateral view of palp, of cJ. 



4. On the Nose, the Organ of Jacobson, and the Dumb-bell- 

 shaped. Bone in the Ornithorhynchus. By Johnson 

 Symington, M.D., F.R.S.E., Lectiu-er on Anatomy, 

 Minto House, Edinburgh \ (Communicated by Frank 

 E. Beddard, M.A., F.Z.S.) 



[Eeceived November 5, 1891.] 



(Plates XLIII. & XLIV.) 



Notwithstanding the great amount of attention that has been 

 devoted to the anatomy of the Ornithorhynchus since its discovery 

 nearly a century ago, its nasal cavities appear to have been, to a large 

 extent, overlooked. 



Meckel (1), Owen(2), Albrecht (3), Turner (4), Zuckerkandl (5), 

 and Parker (6) have examined and described certain portions of 

 the nose, but no account of its microscopic structure appears to 

 have hitherto been published, and several points in its naked-eye 

 anatomy have been overlooked or misinterpreted. 



The following communication is based upon the study of a series 

 of coronal sections of the head of a nearly adult female, together 

 with the examination of several dissected specimens and macerated 

 skulls. The sections were cut after having been decalcified and 

 embedded in paraffin. Most of the Ornithorhynchi which have 

 reached this country have not been sufficiently well preserved to 

 admit of their microscopic examination, and I am greatly indebted 



^ From the Embryological Laboratory, University of Edinburgh. 

 Proc. Zool. Soc.— 1891, No. XXXIX. 39 



