572 5. Entwicklungslehre. 



the author concludes that these cases completely disprove the hypothesis of 

 hypoblastic origin. Doncaster (Cambridge). 



1200) Sauilders, A. M. C. and M. Poole, The Development of Aplysia 

 punctata. 



(Quart. Journ. Micr. Sei. 55,3. p. 497—539. 1 plate. 20 text figs. 1910.) 

 A detailed description of the early development of this Mollusc, tracing 

 the development of the organs from the aecount of the cell-lineage given by 

 Carazzi. The most important feature is the large extent and early appearance 

 of the coelom. The whole mesoderm arises from the cell known as 4 d , which 

 is established in the 24-cell stage. In the embryo before hatching a scattered 

 group of mesoderm cells is found between the yolk-laden endomeres and 

 the ectoderm. When the ectoderm cells which form the „secondary kidney" 

 have sunk below the surface, near them an aggregation of mesoderm cells is 

 formed, in which a split arises, constituting the coelom. The cavity enlarges, 

 so that in the free-swimming larva the coelom consists of a considerable sac 

 lying dorsally and covering the stomach, intestine and parts of the liver and 

 „secondary kidney". There are two kinds of larval exeretory organs in 

 Aplysia, (1) the „primitive kidneys", each consisting of a large vacuolated 

 cell with small nucleus, lying at the sides of the body at the base of the 

 velum, and probably of ectodermal origin; (2) the „secondary kidney", a 

 Single organ derived from four ectoderm cells which sink in and form a 

 pear-shaped organ, vacuoles in which become confluent and open into the 

 mantle cavity. Some observers regard this as the rudiment of the permanent 

 kidney, but as it is never connected with the coelom, the authors do not share 

 this opinion. The various exeretory organs in Molluscan larvae are 

 compared and discussed. 



In explanation of the different origins of the mesoderm in various anne- 

 lids and molluscs, the authors suggest that there are certain organ-forming 

 substances in the egg before segmentation, which are homologous throughout 

 the group, but that they become differently distributed among the blastomeres 

 in different cases. Doncaster (Cambridge). 



1201) Kautzsch, (x. (Zool. Inst. Marburg), Über die Entwicklung von 

 Agelena labyrinthica Clerck. 



(Zool. Anz. 35,22. p. 695—699. 1910.) 



Gut herz (Berlin). 



1202) Budow, Entwicklung der Blattwespen, 1. Cimbicidae. 

 (Intern, entom. Zeitschr. Guben 4,21. p 113—115, 22. p. 120/121, 23. p. 125—127. 1910/11.) 



DieEntwicklungsgeschichte der einzelnen mitteleuropäischen Arten derKnopf- 

 hornwespen wird eingehend besprochen. Zum Schluß werden die bei der Zucht 

 von mehr als 800 Cimbiciden erhaltenen Schmarotzer angeführt. Dabei zeigt 

 sich, daß sich die Schmarotzer nicht an bestimmte Wespen halten, wenn auch 

 nicht zu bestreiten ist, daß einzelne Parasiten gewisse Spezies bevorzugen. 



P. Schulze (Berlin). 



1203) Jürgens, W. (Magdeburg), Über die Larven von Hyperopisus 

 bebe Lac. 



(Blätter f. Aquar.- u. Terrarienkunde 21,11. p. 163. 1910). 



Anschließend an Arnolds Aufsatz in der „Wochenschr. f. Aquar.- u. 



Terrarienkunde", S. 90, 1910 über die Fortpflanzung von Polycentrus Schom- 



burgkii führt Jürgens aus, daß das Verhalten der jungen Tiere dieser Art 



an das Benehmen der von Budgett 1900 geschilderten Fischlarven (wohl 



