10 THE AMERICAN MONTHLY [Jan. 



Studies in the Elements of the Anatomy of the Lower 



Vertebrates. 



By HENKY LESLIE OSBOKN, 

 HAMLINE UNIVKIWITY, bT. PAUL, MINN. 



PART n. 



THE TAILED AMPHIBIAN. 



Amblystoma t'gnnum, The Salamander. 

 CONTENTS. 



1. External Anatomy. 9. The Uro-Genital System. 



2. The Head and Throat. 10. The Muscular System. 



3. The Brain. 11. Fine Structure of Muscle. 

 -4. The Body-Cavity. 12. The Nervous System. 



6. The Heart. 1.3, The Axial Skeleton. 



fi. System. 14. The Skeleton of the Limbs. 



7. The Alimentary System. 15. The Skull. 



8. The Lungs. 



[This discri[itioa is drawn directly from Amblystoma 

 tigpinum, a species that is abundant in the outskirts of 

 Saint Paul, especially in the Autumn months during 

 damp weather. It will apply to any of the urodeles well 

 enough for the purposes of a guide; aud can be used for 

 the frog, though with considerable modifications, especi- 

 :aily for the skeleton of the body.] 



L: External Anatomy.— The characteristic external 

 features as found in the higher vertebrates are readily 

 seen, viz: a division of the body into head^ neck, trunk 

 and post-abdomen; the presence of an anterior and a pos- 

 terior limb. Examine these and note in each three prin- 

 cipal regions: upper, middle and lower which are similar 

 in all but not precisely the same. Of the front limb the 

 upper region is called the brachium, the middle the ante- 

 hrachiuTTiy and the lower the nianus which is again divided 

 into: the carpus or wrist and the digits. The hind limb in 

 a similar manner presents: the thigh, the cms SLudi the pes, 

 which IS divided into the tarsus, and digits. How do these 

 regions compare as to length? What differences do you 

 find between the manus and the pes? How do the limbs 

 compare with those of the frog? Do you recognize the 



