Miscellaneous. 137 



is formed in the interior of the ovule), and a geminal vesicle of 

 0-09 millim. in diameter. The male ovules, the size of which is a 

 little less than that of the female ova, are full of long filaments, 

 which move briskly when isolated. These two sexual elements 

 exist throughout nearly the whole length of the body, from the 

 commencement of the digestive tube to near its extremity. — Comptes 

 Rendus, July 5, 1869, tome Ixix. p. 57. 



Note on the Crustacea tvhich live parasitically in Ascidia in the 

 Mediterranean. By R. Btjchholz. 



The Crustacea living as parasites in the Ascidia have been very 

 carefully studied on the shores of Sweden by M. Thorell, and on the 

 French oceanic shore by M. Hesse. In the Mediterranean these 

 parasites had not hitherto been noticed except cursorily. M. Buch- 

 holz has just carefully investigated ten species at Naples. Except a 

 LicJiomolgus, the whole belong to the family Notodelphyidse, of 

 which M. ThoreU. has described ten northern species. The genera of 

 this family established by the Swedish naturalist {Notodelphys, Do- 

 ropygus, Botachus, and Ascidicola) appear all to belong to the fauna 

 of Naples, which includes in addition the genera Notopterophorus, 

 Ounentophorus, and Goniodelphys. The last two are as yet exclu- 

 sively Mediterranean. 



The most remarkable peculiarity of the Notodelphyidse consists in 

 the exceptional form of the thorax in the females, which gives these 

 Crustacea a very peculiar appearance. This region is modified by 

 the extraordinary development of an incubatory cavity, which re- 

 ceives the eggs descending from the ovaries and preserves them 

 until the complete development of the embryo. This cavity is pro- 

 duced by a transformation of the last thoracic segments (in general 

 the last two) into a part projecting on the dorsal side — a part to 

 which M. Thorell gives the name of the matrical region. 



The movements of these little Crustacea have by no means the 

 vivacity of those of the normal Copepoda. The action of their nata- 

 tory feet is very slow, at least in the adults, and produces a simple 

 creeping along the walls of the respiratory cavity of the Ascidia, 

 rather than a true natation. 



It is not easy to detect the mode of communication of the ovaries 

 with the incubatory cavity. M. Buchholz, however, believes he has 

 ascertained that in the genus Goniodelphys the ovaries open directly 

 into this cavity ; and he thinks, in opposition to M. ThoreU, that 

 this is the case also in the other genera. He is not much disposed 

 to believe that the eggs quit the ovary and pass by the seminal re- 

 ceptacle before entering the incubatory cavity, as M. Thorell supposes 

 to be the case in Notodelphys. The external sexual aperture by 

 which the eggs quit the incubatory cavity is placed upon a little 

 papilla, between the last thoracic segment and the dorsal surface of 

 the abdomen, as has already been indicated by M. Thorell. This 

 observer likewise describes a second sexual aperture on the ventral 

 surface. The seminal receptacles are described by him as connected 



