764 



The skeleton of the shoulder girdle (see figure 4) was quite normal 

 save for the presence of a small shallow cavity just on the dorsal edge 

 of the glenoid cavity, with which the extra limb was moveably articulated. 

 The abnormal arm had a small humerus with a very small but 

 distinct head, its distal end was slightly larger and appeared to be 

 immoveably joined to the radio-ulna. At the distal extremity of the 

 radio-ulna, which was a single bone showing no sign of double origin, 

 was a small partly fused bone probably representing one of the carpalia. 



CR. 



Fig. 4. Bones of Pectoral Girdle and Arms of Right Side of Specimen B. E. Epi- 

 sternum; Ó, Omosternum ; St, Sternum; X, Xiphisternum; A.G, Auxiliary Glenoid 

 Cavity; J?', Radio-ulna; Co, Carpal; M\ Metacarpal; P, Phalanx of extra arm. 



Other letters as before. 



The hand was greatly reduced, parts of one digit only being present. 

 These comprised a small bone representing a metacarpal and a single 

 phalanx. 



Bate son (1) calls attention to the fact that in the "enormous 

 majority" of polymelians the extra repetition consists of parts of a 

 complementary j^air and the preceeding two examples are of interest 

 because in both cases the supernumary limb was single with no signs of 

 being paired. 



II. The absence of a right pre-caval vein in two Frogs. 



The first of the two specimens here described, in which there is an 

 entire absence of a precaval vein on the right side, was discovered 

 during class-work dissection in this college and the details of the second 

 were given me by Dr. Woodland. In all other resj^ects, including 

 the remainder of the venous system they appeared- normal adult speci- 

 mens of the common frog Baita teniporaria. 



