258 



STRUCTURE OF GLANDS. 



geries of very large unramified coeca ; * but in the higher mam- 

 malia and in man the wide excretory ducts pass over into 

 finer branched canals, upon which the terminal cells form 

 botryoidal clusters; the cells are on an average from 1 -20th to 

 1-1 5th of a line in diameter. 



[ 424. Among the glands having tubular vessel-like secret- 



Fig. 259. A, B, por- 

 tions of the kidney repre- 

 sented in fig. 258 injected. 

 Fig. 258. Kidney and supra-renal gland A ' of the natural size 5 the 

 of the new-born child, of the natural size. Malpighian bodies, , a, ap- 

 a, kidney ; b, supra-renal gland ; c, artery ; P earm g as P oint s in the cor- 

 d, veins ; e, ureter. tical substance ; b, the pa- 



pilla of one of the tubular 

 pyramids. B, a small por- 

 tion of A, seen under a 

 simple lens and slightly 

 magnified; a, Malpighian 

 bodies ; b, tubuli urimferi. 



coecal tubes to the most complex form observed in the glandular system. 

 Recent inquiries, however, rather lead us to conclude that the bony fishes 

 in general have a pancreas, which is comparable in } 11 respects to that of 

 the other vertebrate animals ; perhaps the coecal appendages which were 

 so long mistaken for the pancreas have a totally different function. 



* See Meckel : Ornithorhynchi paradoxi descript. Anatom. Tab. viii. 

 and Owen on the Mammary Gland of the Ornithorhynchus, in Philos. 

 Trans. 



