THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[FOURTH SERIES.] 

 No. 105. SEPTEMBER 1876. 



XVIII. — The Development qflhe Ova o/' Clithonius I'w the Body 

 of the Motherland the Formation of the Blastoderm. Bj 

 Anton Stecker *. 



The investigation of the first stages of development of the 

 ova of Chthon ius f possesses a much greater interest than 

 would be supposed from what has hitherto been published 

 upon it ; for, except the memoir on the developmental his- 

 tory of C/^e7|ygr published by MetschnikoiF | in the year 1871, 

 I can cite no other work containing any details of the embry- 

 ology of the Chernetidse. But as Metschnikoff only had 

 scanty materials, the first stages of development observed by 

 him, so far as they relate to the formation of the deutoplas- 

 matic nutritive vitellus and the blastoderm, are so briefly de- 

 scribed, that his work (as, indeed, he himself remarks §) remains 

 very imperfect in this respect. I was fortunate enough to 

 be able to obtain a great number of egg-bearing females of 

 Chthonius^ and thus had the opportunity of thoroughly inves- 

 tigating the first phases of those ova which are still in the 

 ovary and therefore had to be obtained from the body of the 

 mother by preparation ; but as I had at the same time brought 

 up a number of other females in captivity, I was placed in the 

 favourable position of being able to examine simultaneously and 



* Translated by W. S. Dallas, F.L.S., from a separate impression of the 

 memoir published in the ' Sitzungsberichte der konigl. bohm. Gesellsch. 

 der Wiss.' 1876, Heft 3. 



t Chthonius, a genus of the order Chernetidse, family Obisinse ; Chelifer, 

 also a genus of Chernetidse, of the family Cheliferinse. 



X Zeitschrift fiir wiss. Zool. Bd. xxi. (1871) pp. 513-526, pis. 38 & 39. 



§ Metschnikoff, /. c. p. 514. 

 Ann. d' Mag. N. Hist. Ser. 4. Vol. xviii. 14 



