;34 



BULLETIN OF THE 



The Heart. — This, when first seen, was a granular body beneath 

 and close to the stomach ; and its position seems to confirm Vogt's 

 conjecture (p. 45) that it is derived from the digestive tract. 



The Testis;. — This is at first (Figs. 33 and 34, t) a muss of cells, 

 under the digestive organs and behind the heart, and therefore, as has 

 been already pointed out, in the position occupied in the solitary 

 embryo by the ekeoblast, with which it agrees in appearance at first, 

 but it does not become excessively developed, as this does; and in 

 Fig. 34, t, it is shown as a compact globular mass of cells. As devel- 

 opment advances, it spreads out over the surface of the digestive 

 organs, and in the adult it presents the irregularly branched glandu- 

 lar appearance shown in Fig. 5. 



The Ovary and E<j<js. — Soon after the partition grows out from 

 the pericardium and divides the tube into two chambers, and before 

 t he constrictions make their appearance upon the outer wall of the 

 tube, a long club-shaped organ (Figs. 27 and 28, y) is seen within 

 each chamber. These seem to lie free within the sinus cavity, and 

 they could not be seen to be derived from any of the pre-existing parts 

 of the embryo or of the tube; and the way in which they make their 

 appearance seems to indicate that they are formed directly from tb" 

 blood. The elseoblast begins to disappear at about the same time, 

 and as the blood which passes through the latter goes directly to the 

 tube, it is possible that some of its nuclei or smaller cells are thus 

 transported to the tube, and form the basis of the new organs. This, 

 however, is purely conjectural, as nothing was seen which indicated 

 that the club-shaped masses were thus formed. 



Fig. 32. 



Fig. 31, chain-salpa, before the formation of the intestine. Fig. ?,'2. chain-salpa, somewhat 

 older, showing the manner in which tin- muscular bands are formed : b, outer tunic ; r, wall 

 of branchial sac; </, atrial tunic; e, branchial aperture; /, muscular girdles; g, atrial aper- 

 ture ; //, branchial cavity ; I, atrial cavity ; d i, digestive cavity; tl i", wall of digestive cavity; 

 /.■. peripharyngeal ridges; I, epipharyngeal folds; m, endostyle ; », gill; ?•, heart; s, egg ; /, 

 testicle ; r, ganglion. 



