Miscellaneous. 419 



the simple and social Ascidia, but throughout its whole length. 

 The cardiac fissure, iu fact, is situated upon the convex surface of 

 the crescent formed by the heart ; it therefore, as it were, turns its 

 back to the epicardiac sac, which can thus no longer, as in Clavelina, 

 be applied to it to close it. 



The cells of the cardiac epithelium present a row of muscular 

 fibrillce towards the cavity of the heart ; their nuclei, on the con- 

 trary, are situated towards the pericardiac cavity. Neither the 

 vessels nor the heart present any endothelium. 



Dir/estive Tube. — All along the terminal intestine wo can very 

 easily see the composite tubular gland which Huxley was the first 

 to indicate in all the groups of the Tunicata, but the existence of 

 which has lately been denied, even in the simple Ascidia. This 

 gland is formed by a quantity of small tubes terminating csecally, 

 which pour their secretion into the stomach by a common duct. 



The anus presents a wide process, which projects into the inte- 

 rior of the cloacal cavity. It is further surrounded by several 

 transverse muscular sphincters. 



The cloacal cavity elongates considerably during reproduction, to 

 become transformed into a cavity of incubation in which the embryos 

 are developed. The oviduct, which opened into the cloaca by the side 

 of the deferent canal, takes part in the formation of the incubatory 

 chamber ; while the upper lip of its orifice remains applied against 

 the deferent canal, its actual aperture is carried to the very bottom 

 of the incubatory cavity. The cloacal aperture is remarkable for a 

 series of tonguelets or plates, exclusively belonging to the epi- 

 thelium. 



Generative Organs. — These are situated in the postabdomen, on 

 the same side of the epicardiac lamina, in the dorsal face of the 

 animal. The ovary is placed in front of the testis. There is a 

 very distinct oviduct, applied throughout its whole length against 

 the outer surface of the deferent duct ; this oviduct is flattened and 

 bounded by an unciliated epithelium, while the deferent duct is 

 rounded and bounded by vibratile epithelium. 



The ovary presents a cavity which is continued directly into that 

 of the oviduct ; this cavity is bounded by a flat epithelium, which, 

 at certain points, becomes a typical germinative epithelium. It is 

 at the expense of this germinative epithelium that the ovarian 

 follicles are developed ; these are never detached from the epithe- 

 lium from which they originated. The mature ova fall into the 

 ovarian cavity, to be expelled through the oviduct. 



The ovary and the testis are never in function at the same time. 

 — Comptes liendus, September 13, 1886, p. 504. 



A new Form o/Opalina. By M. N. Warpachowskz. 



The author describes a new form of parasite which he has met 

 with abundantly in the body-cavity of young earthworms. The 

 animal shows the general characters of Opalina and somewhat 

 resembles Opalina filum, (^lo,"^., in external form ; but it is distin- 

 guished from all other species of the genus known to the author by 



