216 



frontal and postfrontal bones, and has the molar arch formed as in 

 Anomodonts. « 



W. N. Parker 8 , Symington . Broom und G. E. Smith wiesen 

 nach, daß die Monotremen in der Entwicklung des Jacobson- 

 schen Organes den Sauriern und Schlangen ähnlich sind. Parker 

 sagt: The young Echidna resembles Omithorhynchus in possessing: »A 

 highly developed Jacobson's Organ, resembling that of Lizards and 

 Snakes, enclosed in an independent tubular cartilage, and possessing 

 a large »turbinai« supported by a cartilaginous shelf continuous with 

 the investing tube. « 



Dann sagt er weiter: »Symington 9 is probably correct in his 

 opinion, that Jacobson's Organ reaches its highest development in 

 the Monotremes — higher even than in Lizards and Snakes, in 

 which it presents many points in common with that of the Prototheria.v. 



G. E. Smith 10 beschrieb einen jungen Omithorhynchus und 

 machte über sein Jacobson'sches Organ diese Anmerkung: »In general 

 appearance it presents a considerable resemblance to the adult condi- 

 tion of the organ in Tropiclonotus natrix, described by Dr. J. Beard.« 



Die Arbeit von J. T. Wilson 11 , welche über die Nasengegend 

 von Omithorhynchus und Echidna handelt, konnte ich mir nicht ver- 

 schaffen. 



R. Broom 12 äußert sich in seiner Arbeit über das Jacobson'scbe 

 Organ in folgender Weise: »The existence of the turbinai process in 

 the organ in Monotremes is a point of peculiar interest, as no simi- 

 lar process has been detected in any higher mammal, and as it recalls 

 the turbinai process of the organ in Lizards as pointed out by Sy- 

 mington. Though the organ is clearly not a near relative ofthat in 

 the Lizards, there is considerable affinity between the organ in 

 Omithorhynchus and that in the Agamidae and the Geckonidae. A 

 transverse section in the organ in a ripe embryo of Gecko indeed 

 bears a very close resemblance to the section through the organ in the 



8 W. N. Parker, On some Points in the Structure of the young of Echidna 

 aculeata. Proceed, of the Zool. Soc. London, 1894. 



9 Symington, J., On the Nose, the Organ of Jacobson, and the dumh-hell- 

 shaped Bone in the Omithorhynchus. Proc. Zool. Soc. 1891. p. 575. 



w G. Elliot Smith, Jacobson's organ and the olfactory bulb in Omithorhyn- 

 chus. Anat. Anz. Bd. XI. 1895. 



11 Wilson, J. T., Observations upon the Anatomy and relations of the 

 »dumb-bell-shaped« Bone in Omithorhynchus, with anew theory of Homology, and 

 upon a hitherto undescribed character of the Nasal septum in the genera.' Omitho- 

 rhynchus and Echidna. Proc. Linn. Soc. N. S. Wales, 1894. 22 p. With 2 plates. 



12 P.. Broom, On the organ of Jacobson in the Monotremata. Journ. Ana- 

 tomy and Physiol. Vol. XXX. N. S. Vol. X. 1896. 



