446 Bibliographical Notices. 



morphosis of the larva takes place, a sort of process is developed from 

 the thorax (well compared by Mr. Darwin with that which supports 

 the antennae and eyes in Lucifer) bearing the antennse and eyes upon 

 its extremity, and not, as had been supposed, constituted by the union 

 of the former. It is this process which becomes the peduncle of the 

 future Lepas in the following manner. The larva fixes itself by the 

 suckers of its antennse, and then pours out from its cement-ducts a 

 quantity of chitinous cement, by which it becomes glued to the surface 

 of attachment. The compound eyes are exuviated (to be replaced by a 

 single deep-seated eye in the adult), but the antennse remain, and may 

 always be discovered even when the animal has attained its full deve- 

 lopment. At the same time a still more important and remarkable 

 change goes on in the remainder of that glandular organ to which we 

 have referred as giving rise to the cement-gland. It sends out rami- 

 fied processes, part of which remain in the body of the animal and 

 part occupy the peduncle, in which ova are developed ; so that, from 

 what was apparently one glaud we have two formed, the cement- 

 gland, whose duct opens externally in the antennse, and the ovary, 

 which never developes a duct at all. Well may the author 

 say, that this is "perhaps the most curious point in the natural 

 history of the Cirripedia." We do not think, however, that it is 

 quite so anomalous or without analogy in other divisions of the animal 

 kingdom as Mr. Darwin appears inclined to suppose ; for, putting aside 

 the egg-pouches of Cyclops and the well-known glands which secrete 

 an adhesive substance in the female Epizoa, and which are diverticula 

 of the common genital tract, we may refer to the genitalia and 

 Wolffian bodies of mammals as presenting very similar relations. 



It is worth remark also, that in Argulus, Leydig (Siebold and 

 KoUiker's Zeitschrift, 1852) describes a cephalothoracic spine with 

 glands and ducts occupying a position not altogether dissimilar to 

 the cement-gland. 



The respective import of the organs now recognised as generative 

 has been the subject of a great diversity of opinion, expressed by 

 Hunter, Cuvier, Burmeister, Wagner, St. Ange, Mayer, Steenstrup, 

 Goodsir, Leuckart, and Siebold. The truth appears first to have 

 been made out by Wagner and St. Ange, and the exact structure of 

 the testes vdth their ducts, and of the ovaries, was carefully described 

 by Leuckart (Zur Morphologic und Anatomie der Geschlechtsor- 

 gane, 1847), whose accoimt fully agrees in essentials with that of 

 Mr. Darwin. Like him he was unable to discover any external ovi- 

 ducal aperture. On the other hand, Wagner and Siebold (Vergleich. 

 Anat. p. 485) describe as au oviduct a canal extending " from the 

 lower extremity of the valve of the shell downwards on the cor- 

 responding side of the foot (peduncle), and opening above by a 

 narrow cleft into the mantle cavity," which is also described by 

 St. Ange. 



Mr. Darwin has carefully sought for, but cannot find, this aper- 

 ture, and we may therefore conclude that it does not exist. He be- 

 lieves, on the other hand, that the ova are detached within the body, 

 enter the vascular sinuses, and by them are carried to the inner sur- 



