626 SUMMARY OF CURRENT RESEARCHES RELATING- TO 



Endochrome of Diatoms.* — Sig. M. Lanzi records several instances of 

 the occurrence of granular endochrome in placochromatic, and of un- 

 divided endochrome-discs in coccochromatic diatoms. In the former case 

 the girdle-bands were always broad, from which the author concludes that 

 propagation took place by division of the cell-contents. Amphora ovalis 

 be has seen in various stages of development without previous conjugation 

 or formation of resting-spores. Nitzschia Palea he has also been able to 

 trace in its development from very minute gelatinous spores. 



Raising Diatoms in the Laboratory.! — Prof. S. Lockwood gives 

 various details of a series of experiments he has been making on raising 

 diatoms in a laboratory. An experiment made in Dec. 1882, and since 

 frequently confirmed, demonstrated that diatoms originate from spores. 

 These spores are exceedingly minute, passing easily through filter-paper. 

 They are probably immotile resting-spores, and may be held in suspension 

 a while, like the mineral matters in turbid water. The viability of these 

 spores is remarkable. The diatoms raised in one series of experiments 

 were i'rom spores whose life-force had lain dormant in total darkness for 

 thirteen or fourteen years; and in another series sixteen years. The 

 viability of some genera is greater than that of others. This is notable of 

 Navicula in these experiments, and is consonant with the numerical lead of 

 this genus in forms or so-called species. 



Owing to the environment becoming abnormal, development may be 

 rapid and erratic to a surprising degree, but upon aberrant and asym- 

 metrical lines. Suppressed at some points, the life-energy is precociously 

 active at others. Diatoms have embryonal stages or forms, with silicate 

 fronds. As to kind and quantity, the crops are capricious and vary without 

 apparent reasons. As to the parentage of the spores, they were not in 

 these experiments generated in the vessel, but were derived from sporangial 

 mother-cells. 



The author performed in all twenty experiments; he found that the 

 diatoms generated could be referred to three genera, i.e. Nitzschia, 

 Amphora, and Navicula. 



A table containing the measurements of each accompanies the paper : 

 Nitzschia varies from 1/430-1/414 in. in length and 1/4000-1/6000 in. in 

 thickness, Amphora from 1/1090-1/1500 in. in length and 1/2570-1/5000 in. 

 in thickness, and Navicula from 1/1090-1/4000 in. in length and 1/4500- 

 1/12,000 in. in thickness. 



Fungi. 



Latex-receptacles of Fungi.lj: — Dr. G. Istvanfiy and Dr. 0. Johan-Olsen 

 classify the latex-receptacles and similar structures of the higher fungi 

 under three heads,, viz. (1) Latex-receptacles proper ; (2) oil-receptacles ; 

 (3) pigment-receptacles, or those which contain a substance which colours 

 in the air. 



The latex-receptacles proper or latex- tubes are of large diameter com- 

 pared to the surrounding hyphse, have a very soft extensible cell-wall, and 

 exude, on being cut, a turbid finely granular fluid varying in colour accord- 

 ing to the species. Their form does not vary greatly ; they are seldom 

 divided by transverse septa, but are usually much branched; they are 

 connected with the contiguous tissue-hyphae, and are often curved or 



* Atti Accad. Pontif. Nuovi Lincei, xxxvii. (1886). See Bot. Centralbl., xxix. 

 (1887) p. 321. 



t Journ. N.Y. Micr. Soc, ii. (1886) pp. 153-65 (2 pis.). 

 + Bot. Centralbl., xxix, (1887) pp. 372-5, 385-90. 



