1884.} 129 [Hyatt 



collars and flagella, and become amoeboid. We have not, in 

 these remarks, any intention of denying the effects of heredity. 

 The protozoonal characteristics, the collars and flagella, are in no 

 way, that we can see, necessarily the products of the mechanical 

 conditions of pressure like the forms of the cells ;. these exhibit 

 the effects of heredity and continued use as plainly as any of the 

 organs of higher animals. Lieberkuhn (Midler's Archiv. Anat. 

 Physiol., 1856, p. 11) describes three layers in the larva during 

 the flagellated stages. An " Epiteliumschicht " of rounded amoe- 

 boidal cells with single flagella. He here notices a fine and sug- 

 gestive distinction between the primitive freedom of the cells in 

 this outer layer and the condition of closer attachment prevalent 

 in more mature membranes. The " Corticalsubstanz" lies next 

 to this internally, and consists of a jelly-mass with scattered, 

 fatty granules ; he also stated that the cells in this when 

 freed by dissection have the amoeboid motions, since described, by 

 Haeckel and others, in the free cells of the mesoderm of sponges. 

 The Corticalsubstanz occupies the centre of the embryo and has 

 a spheroidal form, according to Lieberkuhn. One cannot read 

 this, and the descriptions of the feeding cells (p. 497), and of the 

 ampullae and true cell membranes which he mentions (p. 498) as 

 occurring in the tubes and upon the whole exterior of Spongilla, 

 and the descriptions of amoeboid cells, their movements and 

 granular contents, without seeing that the author had succeeded 

 in optically distinguishing the ectoblast, mesenchyme, and endo- 

 blast in the larva, though unaware of the meaning and impor- 

 tance of his observations and not emphasizing these discoveries. 

 This remarkable investigator fed the Spongilla with carmine 

 and found that the grains were carried into the ampullae, 

 which were situated in the axis of the tubes (one in each tube), 

 that the grains remained in these sac-shaped organs for a time; 

 and that while a part were passed on and out of the cloaca, 

 another portion remained, having been swallowed by the cells of 

 the ampullae. 1 Carter, in the same year and independently of 

 Lieberkuhn (Ann. Mag. ]STat. Hist., 1856, p. 242 ; and 1857, vol. 

 xx, p. 21), repeated these observations, described and figured 

 the " ampulla " and asserted that the cells of the " ampullae " 

 alone swallowed the grains of carmine. He mentions in the same 

 magazine (vol. vi, ser. 4, 1870, p. 330), that the cells of these 



PROCEEDINGS B. S. N. H. VOL. XXIIT. 9 MAY, 1885. 



