1891.] ON THE ANATOMY OF ORNITHORHYNCHUS. 575 



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

 luteis ; ab O. amazonico, E. Sim., prsesertiin differt cephalothorace 

 longiore et humiliore. Ab 0. walckenaeri, M'Leay (sp. quae milii est 

 ignota), verisimiliter distinctus est. 



EXPLANATION OF PLATE XLH. 



Fig. 1. Dysderina principalis, p. 557. Lateral view of palp, of (S . 

 2. Dysderina spinigera, p. 558. Leg. 

 3. . Palp, of c?, lateral view. 



4. Pelicinusmarmoratus, p. 559. Lateral view of palp, of ^J. 



5. Opopma dcserticola, p. .560. Lateral view of palp, of (J . 



6. Ocmops spinimamis, p. 563. Lateral view of leg. 



7. Oonops globimoMus, p. 563. Lateral view of palp, of (S , 



8. Oonops puiicarius, p. 564. Lateral view of palp, of c?- 



9. Oonops Jiguratus, p. 5(54. Abdomen from above. 



10. Ochyrocera arietina, p. .5(56. Lateral view of palp, of c? • 



11. Ochyrocera quinquevittata, p. 56G. Lateral view of palp, of (^ . 



12. Theoclia radiata,-^. b&l. Lateral view of jialp. of (J . 



13. Scytodes longipes, p. 567. Lateral view of palp, of c?. 



14. Scytodes hebraica, p. 568. Cephalothorax from above. 



15. Scytodes bajula, T^. oQ9. Lateral view of palp, of c? . 



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

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



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

 shaped Bone in the Ornithorhynchus. By Johnson 

 Symington, M.D., F.R.S.E., Lecturer 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 

 ariatomy 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, Univereity of Edinburgh. 

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



