Bibliographical Notices. 49 



by diagonal separation. Among known facts none can be com- 

 pared better with this mode of development than that of the Salpce, 

 although even here it differs considerably. The numerous observa- 

 tions which I made last autumn on the Salpce have shown that 

 Chamisso (who had to hear so many ill words on his upright re- 

 searches from several naturalists because they did not accord with 

 their systems) observed in general their development correctly. The 

 SalpcE agree with the Acalephce in this, that it is not the larva, but its 

 progeny, which is developed to the perfect animal : it is not the in- 

 dividual, but the generation, which has become metamorphosed. 



The author observes in conclusion, that Graham Dalyell's obser- 

 vations (' Edinb. Philos. Journ.* vol. xxi. 1836), with which he was 

 only partially acquainted from what had appeared in Wiegmann's 

 ' Archiv' and the ' Isis,' may serve in part to confirm his observations. 

 " His (Dalyell's) Hydra Tuba appears to be the above-described poly- 

 poid Acalepha-larva, on which he also noticed buds ; he moreover 

 observed the diagonal separation by which the radiated Acalephce 

 (Strobila) originate. ' Of these latter he has figured one with eleven 

 and one with eight rays ; in general I have found eight. The qua- 

 drangular column, of which Dal3'ell incorrectly asserts that it jiro- 

 jects on the convex side, is the pendent mouth, at the base of 

 which four organs are mentioned by him (the fold-circles with their 

 tentacula). But in the explanation of the observed pliBenomena, his 

 views differ from mine. In February and March," he says, " the sur- 

 face or disc of some Hydra are furnished with a pendent flexible 

 prolongation of an inverted conical form, &c., which is develojoed 

 into 20 to 30 layers, which gradually separate and become free Aca- 

 lephce. But whence this prolongation arises, and in what con- 

 nexion it stands with the Hydra, he does not state. One might al- 

 most be inclined to think that he ascribes to the polype viviparity. 

 According to my observations, it is the animal itself, the polypoid 

 larva, v.'hich separates into diagonal pieces, beginning above and gra- 

 dually descending towards the base. How the tentacula of the polype 

 disappear, and after all the diagonal pieces have become free, what 

 becomes of the lower part of the stalk, I have, it is true, not yet been 

 able to see. That the polype again fixes itself, as Dalyell maintains, 

 after the disappearance of the prolongation, acquires new tentacula, 

 and again adopts its former form, is opposed entirely to my observa- 

 tions, and appears to be founded upon an erroneously conceived ob- 

 servation." This paper is accompanied by 4 plates containing G4 

 figures. 



3. ' On the curious motion of the Colour-cells (Chromatophores) 

 of Cephalopods,' by Rudolph Wagner. " If everything does not 

 deceive me, these observations lead to a new series of phajnomena of 

 motion in organized nature. A new class of active motions appears 

 here together with the ciliary motion of the sap in a rotatory course 

 in cells, and the motion of the Spermatozoa, which has nothing to 

 do with muscular motion." 



Ann. £y- May. N. Hist. Vol. viii. E 



