ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 293 



other forms. It varies greatly in extent and shape, but the horse-shoe 

 shape is typical. It consists chiefly of capillaries (from the coeliac) and 

 an epithelial tissue in one layer or in several layers. In many cases 

 there are tubular diverticula or ramifications of the epithelial layer. 

 The form of the efferent ducts is very variable. Gas bubbles are formed 

 inside the cells by fragmentation of the nucleus and simultaneous 

 granular degeneration of the cytoplasm. 



Parietal Sense-organs of New Zealand Lamprey.* — Arthur Dendy 

 gives an account of the organs in the "Velasia" stage of Geotria 

 australis. After describing the fore-brain and its derivatives in general, 

 he discusses the pineal organ (right parietal eye), the pineal nerve and 

 its connections, the parapineal organ (left parietal eye) and its relations 

 to the brain, and the accessory structures overlying the parietal sense- 

 organs. 



The evidence derived from the study of Geotria may be summarised 

 as follows : — 



1. The parapineal organ, in its position to the left of the pineal, still 

 sho^ys evidence of its primitive paired character. 



2. The structure of the pineal and parapineal organs is essentially 

 identical, although the former is much more highly developed than the 

 latter. 



3. The connection of each of the two sense-organs with the corre- 

 sponding member of the habenular ganglion pair need no longer be 

 questioned. 



4. The marked asymmetry in point of size of the two habenular 

 ganglia, and of the two bundles of Meynert corresponds exactly to the 

 unequal development of the two parietal sense-organs with which they 

 are connected, and leaves no doubt as to the paired character of the 

 whole system. 



Caudal Circulation and Lymph-hearts in Amphibia.f — G. Favaro 



gives a detailed account of the caudal circulation in the newt, salamander, 

 Proteus and other Urodela, and in the larvae of Hyla arhorea and Bufo 

 vulgaris. 



Artificial Growths.:}: — Stephane Leduc describes artificial growths 

 produced in saccharine media by the addition of KCl, NaCl, KNO3, 

 NH4CI, etc. The growth is characteristic in given conditions. There 

 may be roots, stem, and terminal organs ; they are stable and transport- 

 able ; there is metabolism and nutrition and circulation ; grafting is 

 possible. Analogies with organic growth are unmistakable. 



Leduc's Artificial Organisms. § — Charrin and Goupil have experi- 

 mented with Leduc's artificial organisms made out of sulphate of copper 

 and syrup of sugar, and find that there is no evidence of assimilating 

 power, e.g. of utilising sugar. 



* Quart. Journ. Micr. Sci., li. (1907) pp. 1-29 (2 pis.). 



+ Atti Accad. Sci. Veneto-Treutino-Istriana, iii. (1906) pp. 122-66 (20 figs.). 



I Comptes Renclus, cxliv. (1907) pp. 39-41 (2 figs.). 



§ Tom. cit., pp. 136-7. 



