As in all flying squirrels, the four legs were connected by a sheet of skin called the "patagium" which is continuous with the body.
"Camps and Trails in China" by Roy Chapman Andrews and Yvette Borup Andrews
On the misuse of the terms parapteron, hypopteron, tegula, squamula, patagium and scapula.
"Handbook of Medical Entomology" by William Albert Riley
The cartilage, moreover, which supports the patagium springs from the elbow.
"The Cambridge Natural History, Vol X., Mammalia" by Frank Evers Beddard