EXCRETING ORGANS. 631 



peritoneum, and suspended freely in the cavity of the abdo- 

 men, to allow of greater motion of the vertebral column with 

 safety, where there is yet no fixed sacrum. They have a 

 deeply lobulated or folded structure, consisting of a long 

 series of flat imbricated tortuous transverse lobes, or regular 

 sinuous folds of their exterior tubulated portions, resembling 

 externally so many small kidneys pressed closely together. 

 The contorted and convoluted tubuli composing each of 

 these lobes, pour their thick white viscid secretion, consist- 

 ing chiefly of uric acid, by a single orifice into the common 

 ureter, without forming a pelvic enlargement, and without 

 the calices developed in the more concentrated forms of the 

 kidneys of mammalia. 



The narrow tubular ureters follow along the inner margin of 

 the kidneys, receiving successively the short wide common 

 ducts of all the separate lobes, and open by distinct orifices 

 into the back part of the cloaca, as in other oviparous ver- 

 tebrata, whether provided with, or destitute of, a urinary 

 bladder; sometimes, however, a small vesicular dilatation 

 is formed on each ureter before it opens into the cloaca. 

 The blood-vessels penetrate from the exterior of the kidneys 

 between the lobes, and appear to have been mistaken by 

 Huschke for tubuli uriniferi ramifying through the lobes. 

 The affinity of the anguine serpents to saurian reptiles, so 

 obvious in most parts of their structure, is seen also in the 

 presence of a urinary bladder in these species, which is of 

 considerable size in the pseudopus ; and the two short 

 kidneys of the anguis are placed on the same transverse 

 plain of the body, as in higher reptiles. The small white 

 tortuous tubuli uriniferi preserve the same size and diameter 

 throughout the substance of each lobe, and the same tortuous 

 diverging course to their periphery, so that there is yet no 

 distinction of cortical and medullary portions of these organs, 

 as is seen in the kidneys of mammalia. In the long narrow 

 kidneys of the embryo, the tubuli are short, cylindrical, and 

 straight, and extend separately from the ureter, through the 

 soft blastema, with little regularity in their arrangement or 

 in their course ; they commence in the embryo earlier than 

 the suprarenal capsules, near to the cloacal end of the trunk, 

 on the dorsal side of the corpora Wolffiana, as two narrow 

 white opaque bands of blastema, along the inner edges of 

 which, the ureters and the rudimentary tubuli make their 



