1897] MICROSCOPICAL JOURNAL. 203 



DIATOMS. 



Reproduction of Marine Diatoms. — Mr. G. Murray 

 records some remarkable observations on the mode of 

 propag-ation of certain pelag^ic diatoms collected off the 

 coast of Scotland, chiefly belong-in*^ to the g-enera liuddul- 

 phia, Coscinodiscus, and Chertoceros. In Biddiilpdia 

 mobiliensis, "cysts" were observed within the parent 

 cell, with only slig-htly silicified membrane, and destitute 

 of the characteristic spines. These cysts appear to have 

 the power of dividing- and multiplying- before assuming- 

 the characteristic parent form. A similar phenomenon 

 was observed in Coscinodiscus concinnus, but in this 

 species the protoplasm divides before the production of 

 the "cysts,'' two of which were found within the same 

 parent frustrule, differing- from one another in form and 

 in the width of the g-irdle-zone. It is not uncommon to 

 find the young- colonies of Coscinodiscus in "packets" of 

 eig-ht or sixteen ; this being- apparently the result of fur- 

 ther binary division within the frustules, which are found 

 accompanying- them in an empty state. The membranes 

 of these young- colonies are only very slig^htly silicified or 

 not at all ; and they are, therefore, capable of increasing- 

 in size. A similar formation of "packets" of eig-ht or six- 

 teen young- individuals within the parent frustule was 

 observed in several species of Cha^toceros. — Proc. Royal 

 Society of Edinlnirg-h. 



NEW PUBLICATIONS. 



A Text Book of Histology. By Arthur Clarkson, Pp. 

 554, and 174 orig-inal colored illustrations. Bristol: J. 

 Wrig-ht & Co. Price 21s. net. 



In it will be found a full account of the latest, well-authen- 

 ticated discoveries in the microscopic anatomv of the 

 human body, and a very complete description of the pre- 

 liminary processes necessary for making- either temporary 

 or permanent microscopical preparations of the various 

 tissues. The colored illustrations form a prominent fea- 



