1898.] 



AMAZOIflAN LEPIDOSIEEX. 



855 



antlers in form. The right fore-limb (fig. 2) has two principal 

 branches, the oral with three smaller branches, the aboral with 

 two only. The opposite left fore-limb (fig. 3) has two lateral 

 branches, not ramified, and directed downwards, instead of upwards 

 as on the right limb. 



Fig. 2. 



Fig. 3. 



Fig. 2. Head of living Lepidosiren, showing the ramifications of the fore-limb. 



Fig. 3. The same on the left side. The three slight eminences on the upper side 



of the limb show the commencements of further appendages. 



"What is the signification of these formations ? I think I am 

 right in interpretiog them as casual and accessorial appendages 

 with respiratory functions — a sort of very singular secondary or 

 complementary external gills, produced mainly by the necessity 

 of increasing the respiration-surface during life in a small aquarium. 

 I cannot find any other plausible explanation of the phenomenon. 



It is known that the AivK&nProtopterits occasionally exhibits some 



