GASTKODES I'ARASITICUM KOROTNEFF. 79 



in tlic centre of the capsular cavity in examples of lar<ye sizes. It is 

 globular in form and is made up of spherical granules, to each of which 

 is attached the nucleus of its matrix cell. The mass is supported by 

 some "balancers" {hat) which are made up of peculiar long cilia borne 

 by cells situated close to the bottom part of the wall just referred to. 

 The entrance into the cavity of the sense-organ is beset with long 

 cilia, which construct together a covering over the capsule {c2l). The 

 existence of polar plates could not be made out with certainty, although 

 it is possible that, the parts of the epidermis directly outside the capsule 

 which contain nuclei in 2 or 3 strata would represent them. In indivi- 

 duals of smaller sizes the aboral sense-organ may be represented by 

 a simple thickening of the dorsal epidermis, where neither otolithic 

 granule nor any ciliary covering has been formed as yet (PL 8, fig. 

 15, s). 



Tentacular Apparatus. 



The tentacular apparatus consists of the tentacle-sheath, tentacle- 

 basis and tentacle-stem, all of which are developed much in the same way 

 as in ordinary ctenophores. The tentacle-stem (PI. 8, fig. i, PI. 9, figs. 

 3 & 4; t. St) is quite short and simple and has no branches altogether; 

 otherwise it agrees perfectly with that of ordinary ctenophores. It is 

 composed of a muscular core and an epithelial covering (fig. 4). Several 

 nuclei (;/) of relatively large sizes are found in the core; evidently, 

 they belong to the tissue cementing muscle-fibres together. Some of 

 the cells of the epithelium contain a vesicular nucleus and numerous 

 refringent granules {col) — these cells are the primordia of the colloblast. 

 The tentacle-sheath (fig. 3, /. sh) is much shallower than that of 

 ordinary ctenophores; indeed, it can hardly be called sheath. Its inside 

 wall is thickened into a pad-like structure, the tentacle-basis (PI. 8, fig. 

 I, PI. 9, fig. 3; /. d), which contains quite numerous nuclei superposed 

 in several layers. In very small individuals the tentacular apparatus is 

 entirely lacking. 



G astro- V asc iilar System. 



The opening at the centre of the ventral surface of the body leads 

 dorsally into a tubular passage (PL 8, figs. 3-7, ii, 13, 15, 16; oe). 

 This passage is elongate in the transverse direction in large examples 



