476 SUMMARY OF CUERENT RESEARCHES RELATING TO 



It consists of a layer of tall epithelial cells, covered externally by trans- 

 parent cuticle, internally by the pigment layer of the skin. "^ Each cell 

 is narrow and of considerable height. Whilst the basal part contains 

 the nucleus and deep-staining clear protoplasm, the more proximal parts 

 scarcely stain at all, and are filled with secretion products. 



c. Greneral, 



Fauna of Salt Marshes.*— P. de Beauchamp has studied the fauna 

 of the salt marshes of Socoa (Basses-Pyrenees) and makes a preliminary 

 note. He reports the occurrence of several Protozoa {Tintinnidium 

 inquilinum, Cothimiia crystallma, Vorticella microstoma, etc.) : an unpig- 

 mented species of Hydra ; several Turbellarians, such as MonoopJiorum 

 graffi, Socorria uncinata, and ArcMloa rivularis ; the characteristic Poly- 

 chast Nereis {Hediste) diversicolor ; half a dozen Rotifers, two Gastro- 

 pods— ^?/c/roZ^i'^ (Pen'^i^^i/?.) w/z'as and Li?napojit'ia nigra; several Crus- 

 taceans, of which SiJhseroma serratum was determined ; and some insect 

 larvae. 



Nature of Lymphatic Ganglion. f — E. Retterer and Aug. Lelievre 

 find that from the very outset the lymphatic ganglion is a blood-forming 

 structure. In the primordium islets of blood-corpuscles are formed at 

 the expense of the tissue of the nodule. The cytoplasm becomes vacuo- 

 lated and absorbed, and sinuses are formed with hsemoglobin-containing 

 nuclei. These areas persist for some time in the embryo, while the lym- 

 phatic circulation continues to be very slow. When the lymphatic cur- 

 rent increases in rate, it bears away the nascent blood-corpuscles, and the 

 ganglion, hitherto heemo-lymphatic, is transformed into an ordinary 

 (greyish, not reddish) " ganglion." But the structure and the functions 

 remain the same as before. 



Pigmentation of Axolotl LarvaB.J — Fritz Pernitzsch has studied 

 the differences between the larvae of the dark and light races of Axolotl, 

 in order to discover wherein the actual distinction between these two 

 contrasted (Mendelian) conditions consists. He finds that the pigment- 

 cells in the two kinds of larvgg are differently distributed on the body, 

 so that apart from the quantity of pigment, there is a difference in 

 pattern. Moreover, there are types of pigment-cell in the one race 

 which are absent in the other. There is no ground for the assumption 

 that the capacity of the pigment-cells to form pigment is different in 

 the two races. The number of pigment-cells is greater in the dark 

 larvie, and this is true of the different kinds of pigment-cells in differ- 

 ent degree. It is probable that the pigment-cells of the dark larvae are 

 on an average larger than those of the light larvag. 



The author is led to the conclusion that the partial albinism of the 

 light forms depends upon a developmental inhibition which slows the 

 growth and rate of division of the pigment-cells. The difference in 

 pattern is also correlated, for in the light larvse the pigment-cells are 



* Bull. Soc. Zool. France, xxxviii. (1913) pp. 172-8. 



t C.R Soc. Biol. Paris, Ixxiv. (1913) pp. 1274-7. 



X Arch. Mikr. Anat., Ixxxii. (1913) pp. 148-205 (3 pis. and 5 figs.). 



