514 DR. J. ANDERSON OK THE PLASTRON OF 



home. Aug. 12tb, she made her first visit at 7.40, and still 

 went to the closed window. Aug. 13th, her first visit was at 

 6.15 ; she went to the closed window and remained buzzing 

 about there till 7, when I caught her and put her out at the 

 open one by which she always entered. Aug. 15th and 16th, 

 she continued to visit the honey, but still always, even after ten 

 days' experience, continued to go to the closed window (which 

 was in the direct line home), though on finding it closed she re- 

 turned and went round through the open window by which she 

 •entered. 



Note on the Plastron of the Grangetic Mud-Turtle (Emyda dura 

 of Buchanan Hamilton). By John Anderson, M.D., F.L.S. 



[Read March 16, 1876.] 



On removing a living embryo of Emyda dura *, B. H., from the 

 egg, it was found doubled on itself through the middle of the 

 plastron, the fold passing transversely a short way before the 

 umbilical area, traversing the line of junction of the two halves 

 of each hyoplastron and the interval between them and the hypo- 

 plastron. The abdominal surfaces of the two halves of the body 

 were opposed to each other ; the neck and head of the embryo 

 rested by their under surfaces on the abdominal aspect of the 

 postumbilical portion of the plastron, the limbs being applied to 

 the sides of the head. Straightening the embryo, I removed the 

 plastron entire, and was astonished to find that it diifered 

 materially in one respect from the generally accepted views re- 

 garding the structure of the plastron of the Chelonia. All the 

 bones, with the exception of the first pair, were arranged around 

 the membranous or semicartilagiuous area of the umbilicus, and 

 were well ossified. But instead of finding only nine bones in the 

 plastron, eleven bones were discovered to be present. The two 

 additional elements, occurring in the position of each hyoplastron, 

 were due to the circumstance that the latter elements had 

 originated in two ossific centres. All the other bones were the 

 same as in the plastron of Trionyx f. Each hyoplastron consisted 



* I haye applied this term to the Gangetic 'Emyda, because it ajDpears to me 

 to be distinct from the Madras species to which the names E. granosa and E. 

 punctata are more correctly refera,ble. 



t Compare Parker's figures &c., from Rathke, of the plastron of the young 

 of this and other genera, pi. xii. figs. 11-17 (' Monog. Shoulder-girdle and 

 Sternum of Vert.' Ray goc. 1868), 



