48 Bibliographical Notices. 



Prof, von Siebold in Erlangen, Dr. Troschel in Berlin, Prof. A. Wag- 

 ner in Munich, and Prof. Rud. Wagner in Gottingen. The abun- 

 dance of excellent original articles in the first number which has just 

 appeared, convinces us that no pains have been spared that this perio- 

 dical should maintain its station among the first-rate journals de- 

 voted to Natural History. In the plan nothing has been altered ; it 

 will, as usual, be accompanied by annual reports ; that on botany, so 

 well executed by the late Prof. Meyen, has passed into the able hands 

 of the celebrated Link. Many of the papers we shall from time to 

 time place before our readers, but for the present we must confine 

 ourselves to merely indicating the contents with a few extracts. 



The first paper by Dr. Erichson is entitled ' A glance at the Clas- 

 sification of the Evertebrate Animals.' 



The second paper by Sars is ' On the Development of Medusa au- 

 rita and of Cyanea capillata* This article confirms the beautiful ob- 

 servations of Von Siebold on the younger stages of Medusa aurita. 

 The author had likewise observed that Strobila is merely a young 

 state of this Acalephe. The results which the study of the develop- 

 ment of these animals has led to are too important not to be no- 

 ticed in this place, and we trust some of the lovers of natural science 

 who dwell near the coast may be induced to lend their assistance in 

 the investigation of this branch of science, in which so much still 

 remains concealed. The author has given at the end of the memoir 

 a summary of the results of his investigations, which we subjoin. 



1st. The oval or ovaU cylindrical young escape from the eggs con- 

 tained in the ovaria provided with vibratile cilia : on the eggs are 

 observed the Vesicula Purkinji and the Macula ( Vesicula) Wagneri ; 

 the yolk exhibits the usual partitions or furcations. The young col- 

 lect in the cotemporaneously developed marsupial pouches appended 

 to the four oval tentacula. 



2nd. They soon quit the mother, and swim, like Infusoria, about for 

 a time, at last adhere to some foreign body, to which they fix them- 

 selves with their unbranched end ; at the other free end a mouth 

 opens, around which a circle of tentacula is gradually formed. 



3rd. In this polypoid condition, which may fairly be termed a larva 

 state, they already multiply, and indeed in the usual manner of Po« 

 lypes, by means of buds and so-called stolones. The new animals 

 thus produced resemble perfectly the larva. 



4th. Lastly, after the lapse of a still undetermined time, the larva 

 voluntarily divides into a number of diagonal pieces, all of which 

 become new animals. These do not resemble the larva, but are dis- 

 coid creatures, which swim about freely ; their periphery is divided 

 into eight rays, bipartite at the extremity ; and they have a quadran- 

 gular, tubular, pendent mouth. Gradually, as they grow, the rays 

 become shorter, the spaces between them where the marginal ten- 

 tacula issue forth grow larger, the mouth divides and changes into 

 four oral tentacula — in short, these animals become perfectly identical 

 with the original mother (the Medusa or the Cyanea). It is, there- 

 fore, not the larva or the individual developed from the egg which 

 is converted into a perfect Acalepha, but its progeny, originated 



