398 Miscellaneous. 



end of the shield; so that, in fact, it is even more free than in Chla- 

 mydophorus. 



In these places it is united by an extension of the skin of the body, 

 which from these parts extends over the whole internal surface of 

 the disk. The whole outer surface of the bony disk is also covered 

 by a very thin skin, which is visible and easily rubs off the animal 

 that has been preserved in spirit. 



The male and female are very like one another in external ap- 

 pearance ; but the penis of the male is very large, and fusiform. 



Observations on the Structure of the Prohoscis of an Hermaphrodite 

 Nemertian from the Marseilles Coast. By M. E. Zeller. 



M. Marion has described, under the name of Borlasia Kefersteinil, 

 a curious Nemertian, the examination of which proves with certainty 

 the occasional hermaphrodism of the TurbeUaria of this group. The 

 importance of this anatomical fact leads me to present to the Academy 

 the results of some investigations made in the laboratory of the 

 " Ecole pratique des Hautes Etudes "of Marseilles, under the direction 

 of M. Marion, in consequence of which it has been ascertained that 

 the Borlasia parasitic upon Phallusia mamiUafa, so frequent in the 

 gulf, must be united vnth. B. Kef erst einii , with which it presents the 

 same sexual organization. It wiU therefore in future be easy to 

 meet with this species, which always exists in great abundance on 

 the branchial tissue of the Ascidia. The anatomical examination of 

 more than sixty individuals has revealed to me some peculiarities, 

 often not verj- observable, in the structure and functions of the 

 proboscis. 



The greatly developed proboscis extends in the dorsal region of 

 the animal from the ganglia to the anus, where it is recurved so as 

 to attach itself to the walls of the general cavity. I have distinguished 

 five parts, namely : — 1, a protractile region : 2, a bulb of the style ; 

 3, a poison-sac ; 4, a glandular region ; and 5, a muscular region. 



The walls of the first four parts of this organ are formed by longi- 

 tudinal and transverse muscles ; the muscular region seems to be 

 formed entirely by longitudinal muscles. 



The protractile region is equal to about one third of the total 

 length of the proboscis ; it passes between the commissures of the 

 cerebral ganglia, is reflexed, and fixed by its terminal portion to the 

 membrane which covers these ganglia. On its muscular envelope 

 we may distinguish a transparent homogeneous layer, roughened 

 with pretty thick papiUoe, resembling more or less elongated mamiUte, 

 upon which I have not observed any vibratile cilia. 



Behind this region is placed the bulb of the stjde, of a more or 

 less rounded form, in the centre of which is arranged the apparatus 

 of attack. The point, which is much drawn out, penetrates by a 

 small aperture into the inferior portion of the protractile part. It is 

 fixed at its base in a sort of ring or ridge which surmounts the haft. 

 The mass of the haft appears to be granular and brownish. 



The style does not float freely in the centre of the bulb. It is 



