) 48 Miscellaneous. 



In the second part of his memoir the author records one or two 

 experiments upon the reproductive power of the Orthoptera, from 

 which it appears that antennae which were almost entirely cut away in 

 the first stages of development certainly again acquired their normal 

 length during the succeeding moults, but assumed a peculiar geni- 

 culate form ; and that a piece cut out of the side of a wing-sheath, 

 (in the last stage but one, for example) was almost entirely replaced 

 at the next moult, although the wing thus treated was finally smaller, 

 and especially shorler, than the corresponding uninjured one. — 

 Bericht der Akad. der TFiss. in Wien, 3rd January, 1866, pp. 6-8. 



On two Hydrozoa of the Mediterranean. 

 By Prof. DE FiLippi. 



In the marine aquaria of the Zoological Museum of Turin, M. de 

 Filippi has met with two Hydrozoa, one of which appears to be 

 new, and the author proposes for it the name of Halybothys ; the 

 other belongs to the genus Eleutheria of Quatrefages. The latter 

 genus, which has been carefully investigated of late years by different 

 observers, has not always furnished the same results ; and this, ac- 

 cording to M. de Filippi, arises from the observations having been 

 made upon different species. Of these, he distinguishes at least three : 

 (1) the original species of M. de Quatrefages, (2) that of M. Clapa- 

 rede, and (3) that of M. Krohn and Mr. Hincks. To the latter the 

 individuals observed at Turin appear to belong. The first is cha- 

 racterized by a terminal knob of nematocysts at the extremity of 

 each of the two branches of its six arms ; the second by the normal 

 existence of eight arms and four gastrovascular canals. M. Clapa- 

 rede, indeed, observed some JEleutherice having eight arms and six 

 gastrovascular canals, and others with six arms and six canals. M. 

 de Filippi thinks that these anomalies may be explained by a confu- 

 sion of two species radiated in accordance with different numbers. 

 Finally, the last species, which was observed by the author to the 

 number of several thousands, possesses, like the second, knobs of nema- 

 tocysts only at one of the extremities of its bifurcate arms ; and the 

 number of radiating gastrovascular canals is normally six. Never- 

 theless fifteen per cent, of the individuals observed presented seven 

 arms and six gastrovascular canals — a variation not very well 

 fitted to confirm the hypothesis that M. Clarapede had two species 

 before him. 



Whatever may be thought of these specific differences, it is certain 

 that the E lent her ice present great differences in their mode of repro- 

 duction. Whilst the Eleutheria of Normandy observed by M. Clapa- 

 rede always bore their germs in the cavity of the subumbrella, M. de 

 Filippi, like M. Krohn, has seen those of the Mediterranean con- 

 stantly bearing buds on the outer surface of the umbrella, and 

 these buds themselves frequently producing new buds before detach- 

 ing themselves from their parent. In this case we find three gene- 

 rations attached to each other, the oldest of which may at the same 

 time contain ova. 



