ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 671 



the Activosphcerium remained swimming actively about in every 

 direction. 



The globules remained quiet for some minutes, and tben began to 

 extend pseudopodial rays. Tiie vacuoles increased in number and 

 arranged themselves close to the exterior of the globules, those of the 

 largest size pushing out the thin protoplasmic covering, so as to pro- 

 duce a strong resemblance to the perfect ActinospJicenum. The 

 resemblance of each globule to the original Actinosphcerium became 

 more and more perfect. The few masses of the original vacuoles also 

 protruded rays, thus conclusively showing that the rays of Actino- 

 spJiceria are not necessarily dependent upon the central mass of proto- 

 plasm. The vacuole masses developed into perfect Actinosjphceria 

 much more quickly than the globules formed of the central proto- 

 plasm, an hour or two being sufficient to the perfect development. The 

 rays of all the immature Actinosphceria were irregular and flattened 

 and in many cases lacked the axial thread. 



The ActinospJiceria moved their pseudopodial rays freely in all 

 directions, the ray being bent close to the peripheral layer of 

 vacuoles. 



From an original colony of eight individuals, a small bottleful 

 was manufactured in the manner above described, the time needed for 

 development being in proportion to the siz3 of the fragments into 

 which the Actinosphceria were divided. The above experiments were 

 tried on many individuals, the only difference of result in the various 

 instances being in the degree of completeness with which the proto- 

 plasm separated itself from the water. It was argued from the above 

 facts that the power of any part of an Adinosphcerium to develope into 

 a perfect individual was inherent, and not dependent upon any 

 peculiar condition of the animalcule. 



Fig. 8, pi. xli. of Leidy's ' Ehizopods of North America,' which he 

 doubtfully refers to the Actinosphce-ria, exactly resembles a medium 

 stage in the development of the globules ejected from the body of the 

 Actinosphcerium. 



The author also stated that the rays of ActlnosphcBrium when irritated 

 by being compressed would be retracted completely on all sides, and 

 would again appear on the cessation of the disturbance. 



The length of time needed for the development of the Actino- 

 sphcBria, in the reproduction by natural means, was from seven to four- 

 teen days ; that needed for the development in the reproduction by 

 artificial means was from one to two days. 



In the latter case this length of time was needed only in cases 

 when the crushing was carried to extremes, as, when the Actinosphcerium 

 was simply divided into small pieces, a few hours were all that was 

 needed to complete the development of the fragments. 



Dimorphism of the Foraminifera.* — MM. Munier-Chalmas and 

 Schlumberger in a second communication on this subject,| prove that 

 in extinct species there is a series of modifications similar to that 



* Comptes Eendus, xcvi. (1883) p. 1598. 

 t See tliis Journal, ante, p. 380. 



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