PACKAKD.] ARTIFICIAL REARING OF THE BRINE SHRIMP. 461 



garcled as fecundated into a new jar, into which they could eventually 

 deposit their eggs. But to be sure that no new brood of Artemia was 

 developed out of the Utah mud added as food, I again took the pre- 

 caution to use only well-boiled mud in which any possible eggs would 

 then be destroyed. The fecundated Artemia females, however, con- 

 tinued to prosper in their new jar, and I soon perceived the activity of 

 their inner generative organs. This activity manifested itself very soon 

 in the two blind ovarial strings situated in their postabdomens; in the 

 interior of those strings white, uniseriately-placed ovarial germs came 

 into view, which latter grew more and more, their places of contact be- 

 coming flattened. All these eggs in their complete form possessed 

 neither a germinal vesicle nor a yolk-skin. The latter is not formed 

 until the uncovered eggs have entered the upper bent-inward-andback- 

 ward end of the ovarial strings, and then it represents a very tender trans- 

 lucent and homogeneous egg-membrane. I should call these bent terminal 

 portions of the ovarial tubes oviducts, since they enter after a short 

 course a capacious cavity, thelatter certainly functionating as an uterus. 

 The uterus possesses in its walls a very complicated muscular appa- 

 ratus, which, through its active contractions, moves the contents of the 

 uterus in various ways. One can now also observe six cell complexes 

 in three pair of groups on the right and left behind each other, divided 

 and fastened to the uterus walls, which in their organization and mean- 

 ing fully correspond with the egg-shell glands, as observed and de- 

 scribed^ by me in Artemia salina, only with the difierence that in 

 Artemia fertilis three pairs, in A. salina only two pairs of such shell- 

 glands occur. These glands at first appear perfectly colorless, becom- 

 ing gradually amber-5T41ow, finally assuming a rust-brown color, with 

 which coloration the secreting function of these glands begins. It was 

 now interesting and striking to me in these investigations that the first 

 lot of eggs that entered the uterus through the oviduct, which eggs 

 were surrounded by but a delicate yolk-membrane, did not yet receive 

 any hard egg-shells, although they were incessantly moved to and fro 

 by the muscular walls of the uterus. They remained without shells, 

 because the shell-glands had not yet discharged their contents into the 

 uterine cavity, un the other hand, to my greatest astonishment, a 

 perfect segmentation process was going on in the uncovered eggs, 

 which could be closely followed through the tender and transparent 

 yolk-skin. Finally, I perceived the red eye-dot of the now developed 

 Nauplius through the yolk-skin, soon afterwards the entire brood of 

 Nauplii escaping and rowing about in the water. Curiously enough, 

 this parturitive act did not repeat itself in all those females of Artemia 

 which gave birth once, although their uterus was repeatedly filled with 

 tender-skinned eggs; in short, all fertilized females of J.r?emm /(?rit7is 

 became, after first giving birth to live young ones, from this time ovip- 

 arous.^ Whether now all females of Artemia fertilis show the pecu- 

 liarity of always producing live young ones at the first process of 

 propagation and then become oviparous, I can give no decisive answer. 

 The observation seems to me important, which I here, though already 

 mentioned, again repeat, that in raising Nauplii from the "Dauer- 



^ Opus ci tatum, p. 191. 



2 1 had alreatiy occasion to make similar observations on A. salina, and refer to p. 

 190 of op. citat., and there I attempted to express presumptions as to the causes which 

 induce the females of Artemia at one time to be viviparous and at other times ovipa- 

 rous; the correctness of those conjectures I cannot warrant, since I have not yet ac- 

 quired the necessary amount of experience on these striking phenomena. 



