and Structure of the Proteus Anguinus. 19 



afterwards in a right line, till they reach the anterior point of 

 the kidneys, where they make many twistings, and pursue a ser- 

 pentine course, till they arrive at the lower half of those organs. 

 In the females of these reptiles, on the contrary, the ureters are 

 less convoluted, and do not commence at any distance from the 

 kidneys ; whence, it is probable, that froin this difference of 

 form, the ureters of the male may exercise some other office be- 

 sides that of conveying the virine. In Fig. 3. Plate VL, the 

 kidney of a female may be seen. 



But though the kidneys and ureters in the proteus and 

 salamander bear so near a resemblance, the form of the uri- 

 nary bladder in the two animals is quite different. In the 

 salamander, this organ is short, and its fundus bifid. In 

 the proteus it is long, and has a simple fundus; so that it 

 resembles more an appendix coeci of the intestine, than an 

 urinary bladder. It is annexed to the intestine in a point 

 diametrically opposite to that into which the two ureters are in- 

 serted ; in other words, it is inserted into the wall of the intes- 

 tine that looks downward, while the ureters terminate in the wall 

 that regards the spine. In the proteus, therefore, as in other 

 reptiles of the same family (Batraciens,) the ureters do not ter- 

 minate in the bladder, but discharge themselves directly into the 

 intestine, at a point opposed to the bladder. . This fact has led 

 many, and among others Townson and Schreibers, to doubt if 

 the organ named the urinary-bladder, be, in frogs and salaman- 

 ders, a real receptacle for the secretion of the kidneys, or destin- 

 ed to some other office. Townson, supposing the urine poured 

 into the intestine by the ureters to be at once discharged with 

 the faeces, suggests the idea, that the bladder above mentioned 

 may be regarded rather as a reservoir of water absorbed from 

 without, and destined to some particular use in the animal eco- 

 nomy. His words are, " Cum nunquam bibant haec animalia, 

 opus tamen sit iis tantopere aqua, probabile mihi videtur, aquatiT 

 cute absorptam, aut ejus partem induci in vesicam, tanquam 

 in vas quod eam servet ; atque inde distribui, prout econom a 

 animalis requirat, eodem fere modo, quo fluidum receptmn 

 in ventriculum aliorum animalium inde distribuitur *." That 

 the skin of frogs absorbs water, seems demonstrated by the re- 



• See Townson, Observationes Physiologicae de Amiihibiis, &c. 



