Comparative ultrastructural analysis of two tortoise bladders, Testudo graeca and Geochelone carbonaria.

Urinary bladders from the desert tortoises, Testudo graeca and Geochelone carbonaria were removed at specific times during the year and species in all bladders examined: (1) granular cells, (2) mitochondria-rich cells, and (3) basal cells. Cells analogous to these three types have also been observed in amphibian bladders (from toad Bufo marinus and bullfrog, Rana catesbiana) and reptilian bladders (from Pseudemys scripta and Clemmys caspica). Both tortoises have an incomplete layer of basal cells so that the granular and mitochondria-rich cells extend from the lumen to the basement membrane: something was not observed in bladders from bullfrog or turtles. A flask-shaped light cell was observed in the Geochelone carbonaria bladder obtained in April. No counterpart of this cell was seen in the same species sacrificed in January, or in any of the Testudo graeca bladders, although a similar cell has been described in the turtle, Pseudemys scripta (Rosen, Expt. Molec. Path., 12: 286-296, '70). This study was undertaken to characterize the cell types present in tortoise bladder and to compare them with cell types in the bladder of the turtle, bullfrog and toad.