563 



20. Palaeontologie. 



Palaeontographica. Suppl. III. Lief. 8 u. 9. Cassel, Th. Fischer, 1880. 4^. 

 Jl 40, — . 



(Enthält: Verback, Boettger, u. v. Fritsch, Die Tertiärforniation 

 von Sumatra.) 



G-einitz, Hs. Br., Nachträge zur Dyas. I. Mit Beiträgen von Drude, Vetter 

 und Weiss. Mit 8 Taf. Cassel, Th. Fischer, 1880. 4». (Mittheil aus dem 

 Kgl. Min.-Geol. und Praehist. Mus. Dresden. 3. Heft.) M 20, — . 



(p. 33 — 39 : Beitrag zur fossilen Fauna des Geraer Kupferschiefers und des 

 oberen Perm in llussiand.) 



Verbeek, E. D. M., 0. Boettger mnd K. von Fritsch, Die Tertiärformation von 

 Sumatra. I. Theil. Cassel. Fischer, 1880. 4». (120 p., 12 Taf. u. Karte.) 

 Jl 40, — . 



(Auch in den Palaeontographica Suppl. III.) 



n. Wissenschaftliche Mittheilungen. 



1. The Embryology and Metamorphosis of the Sergestidae. 



By W. K. Brooks, Director of the Chesapeake Zoological Laboratory of the 

 Johns Hopkins University. 



The points of especial interest in the development of Leucifer are 

 the following 



1) The Q^^g undergoes total regular segmentation, and the lines of 

 division extend to the centre of the q%^^ where a central segmen- 

 tation cavity is formed. 



2) There is an invaginate gastrula stage. 



3) The larva leaves the q^^ as a Nauplius. 



4) There is a Proto-Zoea stage, but no Elaphocaris stage , and no 

 Acanthosoma stage ; the Proto-Zoea changing into a Schizopod 

 which has the same general form as the adult Lucifer. 



5) The fifth thoracic segment is entirely wanting at all stages of de- 

 velopment. There is at no time any trace of it or of its appen- 

 dages. 



In another Sergestid which Avas studied, probably Acetes, the 

 Proto-Zoea changes into a larva very much like Dohrn's Elaphocaris, 

 but with much shorter eye-stalks, and with the rostrum and spines of 

 the carapace simple. This changes into an Acanthosoma, and this is 

 gradually transformed into the adult by a series of moults. 



The schizopod stage of development is of very short duration, and 

 the exopodites of the walking limbs are soon reduced to very small 

 rudimentary structures which persist for one moult after they have be- 

 come functionally useless. 



