SECRETINO STRUCTURES. -410 



Heiilc, who reforretl them to the same class of structures as 

 the closed vesicular extremities of the ducts of compound 

 glands. Dr. Allen Thomson lias observed, that the primitive 

 condition of the gastric and intestinal gland is a clo.sed vesicle.* 

 Wasmann described the structure of the gastric glands in the 

 pig ; and his description mIII 1)0 fully explained by the 

 following observations and views.f llallman has given a 

 detailed account of the testicle of the ray,+ which closely re- 

 sembles that of the Squuhis comubicus, as described in another 

 part of this chapter. Kone of the recent observations on the 

 development of the spemiatozoa have proved that the 

 vesicles, in which they are formed, are the epithelium-cells 

 of the ducts of the testicle. I am indebted to T)r. Allen 

 Thomson for directing my attention to a notice in Valentin's 

 Bepertormm, 1841, of a Dissertation by Erdl,§ in which he 

 describes, in the kidney of that mollusc, cells, the nuclei of 

 which pass out by the duct of the gland. It does not appear, 

 however, that Erdl had discovered the uric acid within the 

 cell.ll 



If the membrane which lines the secreting portion of the 

 internal sm-face of the ink-bag of Lolirjo safjittata (Lamark) be 

 carefully freed from adhering secretion by washing, it will be 

 found to consist almost entirely of nucleated cells, of a dark- 

 brown or black colour. These cells are spherical or ovoidal. 

 Their nuclei consist of cells, grouped together in a mass. Be- 

 tween these composite nuclei, and the walls of their containing 

 cells, is a fluid of a dark-brosvn colour. This fluid resembles, 

 in every respect, the secretion of the ink-bag itself It 



• rroccedings of the Bri/ish Associalion, 1S40. 



t Dc DigcMionc NonnuUa, Diss. luanq. Burol. 1839. 



X Miilk-r's Archiv, 1840. 



§ iJe Helicis Algirce vasia sanguifcris, 1840. 



II Mr. Rownian lm.s shown tliut tlio fat in tlie fatty livi-r is cuiitiiintil in the 

 secreting ct'lls. — Ohserva turns on the Minute Structure «/ the Fatty Degenera- 

 tion of the Liver, January 1842. 



