972 SUMMARY OF CURRENT RESEARCHES RELATING TO 



discaso was artificially induced by moistening the food of cabbage- 

 worms witb tbo culture-fluids from the jaundiced silkworm larvae. 



In regard, further, to a breeding-cage disease attacking the yellow- 

 necked ajjple caterpillar (Datana ministra) and the walnut caterpillar 

 (Datana angusl), the contagious character and the possibility of 

 infection by the bacterial virus were demonstrated. The cultures (in 

 beef-broth and on thin gelatin films) related to both micrococci and 

 bacilli, which were preserved over winter in plugged or sealed tubes, 

 cultivated the following season, and applied to the food of another 

 species of larva — the zebra caterpillar (Mamestres picta) — with 

 satisfactory results. 



Finally, in a note on " Muscardine," he attributes largely to this 

 affection the disappearance of a vast host of the forest tent caterpillar 

 (Clisiocampa sylvatica) which devastated tho forests and orchards of a 

 part of southern Illinois in 1883. 



/3. Myriopoda. 



Brain of Myriopods.*— M. G. Saint-Eemy has investigated the 

 intimate structure of the Myriopod brain in Scolopendra morsitans. 

 Viewed from above, two transverse pear-shaped lobes are seen. These 

 are applied to one another at their base in the middle line, while 

 terminally they form the optic lobes and give off the optic nerves. 

 They are continued downwards on each side of the middle line into 

 a transversely elongated mass. This mass swells anteriorly to form 

 the two antennary lobes, gives off posteriorly the oesophageal com- 

 missures, and forms medianly a thick transverse commissure from 

 which the unpaired median visceral nerve arises. 



The brain consists chiefly of medullary substance. Cortical 

 layers of cells cover the upper surface, the optic lobes, &c. Over 

 a small portion of the anterior margin of the upper surface of 

 each of the cerebral lobes, the medullary substance is left uncovered. 

 This region stains very markedly with osmic acid. The exact 

 nature of the formation, which is described in detail, was not 

 determined. 



The typical optic lobe, the large antennary, like those of insects, 

 the oesophageal commissures, &c, are briefly described. Tho whole 

 structure resembles the brain of insects more closely than that of 

 Crustacea or Arachnids. 



Sense-organs on antennae and lower lip of Chilognatha.f — 

 Herr 0. v. Eath has studied the histology of the sense-organs on the 

 antennse and on the lower lip of Ghilognatha, and has compared them 

 with those of the crayfish and wasp. 



I. Antennary Sense-organs. — (a) The cones. Leydig was the first 

 to describe conical processes, usually four in number, which occur on 

 the last joint of the antennae. Their nervous relations have been 

 lately investigated by Sazepin. Herr von Eath's results are as 

 follows. The antennary nerve divides at the sixth joint into four 



* Comptes Rendus, ciii. (1886) pp. 288-90. 



f Arch. f. Mikr. Anat., xxvii. (1886) pp. 419-37 (1 pi.). 



