Presence and Absdnce of the Gall-bladder in certain 



Rodents. 



y R. E. Lloyd, Major, I.M.S., Professor of Biology 



in the Medical Golleae. Calcutta. 



[Read at the First Indian Science Congress, Jan. 16th, 1014.] 



A short time ago my attention was drawn to the fact that 

 there was no gall-bladder in the rat. 



Reference to Owen's Anatomy of Vertebrates and other 

 works showed that the fact had long been known, though it is 

 omitted from certain standard works on comparative anatomy, 

 in most of which the absence of the gall-bladder from the 

 horse is noted. 



Owen writes that "the gall-bladder is absent from Mus y 

 Cricetus, Lemmus, Echimys, Ereihizon, Synetheres, also that 

 Cuvier did not find it in Sciurus maximus and in a species of 

 Pteromys, but in that dissected by Hunter (Pt. volucella) it 

 was present, as also in Sciurus cinereus and the common 

 squirrel. The porcupine (Hystrix) has a small gall-bladder 

 and the common Jerboa (Dipus sagitta) has one of the usual 

 size. The Cape Jerboa {Helamys) had it not. In all other 

 Rodents the gall-bladder is present." 



In Flower and Lydekker's well-known work on the Mam- 

 malia we find in the chapter devoted to the Rodents the 

 following statement — "The gall-bladder though present in most 

 is absent in a few." 



In Max Weber's large work on the Mammalia. 1G04, we 

 read, under the heading Rodentia, "The gall-bladder may be 

 absent (Muridae)." 



The subject seemed interesting as bearing on the question 

 of the utility of the gall-bladder, and as a number of Rodents, 

 preserved in alcohol, were available in the Indian Museum, I 

 examined them in order to ascertain whether the gall-bladder 

 was present or absent. The cases observed were as follows : — 



Muridae. 



Number 

 Species. examined. Locality. Gall bladder 



Hub rattus . 2 Calcutta Absent. 



Mus decuman us .. 2 Calcutta Absent. 



Mus mettada 



3 Etawah Absent. 



1 Madras Absent. 



