536 



Brunst bemerken ; nur bei einigen Männchen ließen sich im Hoden 

 und Nebenhoden sehr spärlich ausgebildete Samenkörper nachweisen. 

 Vielleicht war für diese Art die Jahreszeit noch zu früh und findet die 

 Begattung wohl erst später im October und November statt. 



Von anderen Arten erhielt ich nicht genügend zahlreiche Exem- 

 plare, um darüber berichten zu können. 



Aus den mitgetheilten Befunden scheint mir immerhin hervorzu- 

 gehen, daß sich auch selbst schon bei den deutschen Arten der Chirop- 

 teren die Fortpflanzung nicht gleich verhält. Es dürfte sich daher 

 empfehlen, besonders die südlicher vorkommenden Arten einer ge- 

 nauen Untersuchung zu unterziehen. 



3. The Ontogeny of Lìmulus. 



By J, S. Kingsley, D.Sc, Lincoln, Nebr., U. S. A. 



êingeg. 28. Juli 1890. 



The following is preliminary to a more detailed account with 

 ample illustrations which Avill be published soon. The Avork was done 

 in the Marine Biological Laboratory at Woods Holl, Mass., during the 

 summers of 1889 and 1890. In my views of the earlier stages as seen 

 from the surface I fail to corroborate Os horn's account ^ in many 

 particulars. The eggs were artificially fertilized and were carried 

 through until hatching. 



1 ) The segmentation nucleus is subcentral and is surrounded by a 

 thin pellicle of protoplasm. It undergoes several divisions before any 

 signs of segmentation are visible from the surface. The products of this 

 division migrate more rapidly toward that pole of the egg where the 

 germ is subsequently to appear than to any other portion of the sur- 

 face. Forty hours after impregnation the egg itself begins to segment 

 and this segmentation has in its general appearance a mesoblastic 

 character, recalling to a slight degree Metschnikoff's^ pi. XIV 

 fig. 5. The result of this yolk segmentation is to divide the egg into a 

 number of yolk cells, in the centre of each of which there is a nucleus 

 with its thin layer of protoplasm. 



2) The result of migration of the products of egg and nuclear 

 segmentation is the formation of a blastoderm at first on one side of 

 the egg, the cells of which are smaller and less charged with yolk than 

 those of the rest of the ovum. At this time surface views show no traces 

 of regularity. At one pole are numbers of poorly defined small cells 



1 Johns Hopkina University Circulars. No. 4;i. 1885. 



2 Zeitschr. f. wiss. Zool. XXI. 1871. 



