236 Miscellaneous. 



On the Contractile Tissue of Sponges. By N. Lieberkuhn. 



In a recent supplement to his numerous investigations of Sponges, 

 Lieberkiihn has paid special attention to the ciliated embryos of the 

 Spongillae. The ova present a perfectly regular segmentation. They 

 are situated, like the embryos, in lacunae of the parenchyma of the 

 body. It is there also that the spermatic cells are found. To ob- 

 serve the embryos, Lieberkiihn divides the Spongilla into thin sec- 

 tions, which he leaves to soak in water for a day. The embryos up 

 to the moment when they commence their independent life remain in 

 the envelope formed by the contractile tissue of the sponge, in which 

 they turn about by means of their ciliary coat. During this period 

 the cavity of the body, which is filled with liquid, is formed. A 

 portion of the spheres of segmentation which have not undergone 

 much modification are crowded together in the posterior part of the 

 body, where they form an opaque mass. The cilia of the embryo 

 are very long, and implanted upon still amorphous sarcode, and not 

 upon true cells. The mass of the embryo properly so called, 

 however, is formed by contractile and nucleated cells, a portion of 

 which enclose siUceous spicules in their interior. This tissue is iden- 

 tical with the contractile parenchyma of the sponge itself. — Archiv 

 fur Anat. und Physiol. 1867, p. 509 ; Bibl. Univ. 1868, Ball. Sci. 

 p. 168. 



Comparative Investigation of the Generative Organs of the Hare^ 

 Rabbit, and Leporide. By S. Arlong. 



The author gives an account of the anatomy of the generative 

 organs in the Leporides produced by the union of a male and female 

 hybrid between a male hare and female rabbit. 



In certain organs, such as the feet and the ovaries, the Leporide 

 occupies a middle place between the hare and the rabbit. The 

 generative organs are complete in both sexes. In the female the 

 ovaries resemble those of the hare in colour and texture, and those 

 of the rabbit in the volume and dissemination of the Graafian vesi- 

 cles. The vagina and vulva, on the other hand, resemble those of 

 the rabbit in their dimensions, the position of the meatus urinarius, 

 and the extent and arrangement of the canal of Gaertner. The 

 fecundity of these hybrids is shown by their anatomy : the females 

 possess many ovules, and the testes of the males furnish a liquid 

 filled with sperm atozoids. In the mule, Brugnone is the only ob- 

 server who has detected spermatozoids. 



The author concludes with the following summary of results : — 



1. The female hybrid of the hare and rabbit can be fecundated 

 by the male hybrid. 



2. These hybrids, whilst presenting intermediate characters, pos- 

 sess genital organs which much more resemble those of the rabbit 

 than those of the hare. — Coniptes liendm, June 22, 1868, pp. 1267- 

 1269. 



