1888.] MORPHOLOGY OF SUPERNUMERARY PHALANGES. 511 



14. Leydig, F. — Ueber den Eau der Zehnen bei Batrachiera urid 



die Bedeutung des Fersenhdckers. Morph. Jahrb. Bd. ii. 

 pp. 165-196 (1876). 



15. Parker, T. J. — Second preliminary note on the Develop- 



ment of Apteryx. P. R. S. vol. xliii, pp. 482-487 (1888). 



16. Peters, W. C. H. — Reise nach Mossambique. Zool. iii. 

 Amphib. (1882). 



1 7. Ryder, J. A. — On the Genesis of the extra-terminal phalanges 

 in the Cetacea. Amer. Nat. 1885, pp. 1013-1015. 



18. Strasser, H. — Ziir Entwicklung der Extremitatenknorpel 

 bei Salamandra und Tritonen. Morph. Jahrb. Bd. v. 

 pp. 240-312 (1879). 



19. Weber, Max. — Anatomisches iiber Cetaceen. Ibid. Bd. xiii. 

 pp. 616-653(1888). 



VIII. EXPLANATION OF THE PLATES. 



The figures are mostly drawn from tracings of photographs made for ua 

 by Mr. R. Chapman, and to him our thanks are due for the care bestowed upon 

 their production. 



All the figures represent digits of the bind foot. Unless otherwise stated, 

 they represent median longitudinal sections, as seen under a low power. 



Plate XXIV. 



Fig. 1. Hyla arbor ea, late tadpole. 



2. Ehacophorus eques, adult. 



3. Hyla freycineti, adult. 



4. Hyla cmrulea, not fully grown. 



5. Nototrema inarsupiatum, adult ; penultimate joint, to show its ligament 



and annulus apparatus. 



6. The same ; lateral section. 



7. The same animal; to show distal joint. 



8. Xenophrys monticola, adult. 



Plate XXV. 



Pig. 9. Hyla arhorea, tadpole ; to show the primary differentiation of the parts 

 of the digital skeleton. Zeiss D, Oc. 2. 



10. Eana temporaria, larva ; to show syndesmosis of terminal joint. Zeiss 



D, Oc. 2. ^ 



11. Bomhinator hombinus, adult. 



12. Proteus anguinus, syndesmosis of terminal phalanx. Zeiss D, Oc. 2. 



13. Hyla peronii, adult. 



14. Portion of the supernumerary phalanx in the same, more highly mag' 



nified. Zeiss P, Oc. 3. 



15. Spelerpes fusciis, adult. 



16. Sana temporaria, adult. 



Beferenoe Letters. 



an. Annulus. cp. Cartilage corpuscle. I. Inter-articular ligament. Ic. La- 

 cuna, nc. Nunleus. p.p. Penultimate phalanx, p.s. Supernumerary phalanx. 

 p.t. Terminal phalanx, sh. Fibrous tunic of digital skeleton, sy'. Syndesmosis 

 of terminal joint, sy". Syndesmosis of penultimate joint, i". Extensor tendon. 



36* 



