476 Miscellaneous. 



cimens in which the stipulae were largely developed. Of introduced 

 plants, the common water-cress grows by cart-loads in and about the 

 streams for several miles round Wellington; and Mimulus luteus is also 

 spreading itself along the streams and over the swampy ])laces behind 

 the town. He adds that he is very desirous of introducing some of 

 the British plants which would probably thrive, such as Stellaria 

 Holostea and Antirrhinum Cymhalaria ; and states that he brought out 

 with him from England Vallisneria spiralis, of which he has speci- 

 mens intended for the Botanic Garden at Melbourne, from whence 

 it may perhaps make its way to Sydney and Hobart Town. Mr. 

 Ralph concludes his sketch by mentioning a species of Nitella (N. 

 translucens ?) found in a rapid stream about five-and-twenty miles 

 from Wellington. 



MISCELLANEOUS. 



On the Mode of Reproduction and Development in various groups of 

 Zoophytes and Mollusca. By M. Gegenbaur. 



AcalephcB. 



1 . In a new species of Lizzia, the development of the ova takes 

 place in the following manner :— After exclusion from the ovary, 

 which is rent at its external portion, the mature eggs become fur- 

 rowed ; a ciliated oval embryo is then formed, which is soon con- 

 verted into a polypiform larva. This larva, after fixation, acquires a 

 transparent corneous envelope, and throws out from a little below its 

 extremity, four arms disposed in the form of a cross, whilst the mouth 

 makes its appearance at the apex. The embryo of the Medusa has 

 thus become a Polype, which resembles the genus Stauridium of 

 Dujardin. 



2. In a discophorous Medusa, the author saw gemmules arising in 

 great quantity from the inner surface of the stomach ; these gemmules 

 at first presented the appearance of flat tubercles, which, becoming 

 detached from their parent, gradually acquired the form of a bell. On 

 the lower surface of this bell, near its circumference, four protube- 

 rances made their appearance; in its centre a small opening, the 

 mouth was formed ; the protuberances, which are marginal tentacles, 

 soon increased in number, whilst the embryo continued growing. At 

 last these gemmules, the whole development of which took place within 

 the stomach of the mother, produced Medusae, which did not differ 

 from their parent in any respect. 



3. The author considers that in a considerable number of genera, 

 such as Charybdea, Pelagia, Ephyropsis (new genus), and Rhizo- 

 stoma, the marginal organs are composed of an auditory apparatus 

 and an organ of vision. The latter, which have hitherto only been 

 seen by M. Kolliker in an Oceania, are placed close to the auditory 

 vesicles, and attached to a prolongation of the stomachal sacs ; they 

 consist of a hemispheric mass of pigment-cells, in which a spherical 



