ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 969 



protoplasm again gathers. (H) From one or from several regions a 

 protoplasmic fluid is excreted. ( 12) The cells extend longitudinally, 

 and the colony becomes cylindrical. The above-mentioned proto- 

 plasmic fluid gathers at the anterior end. (13) The nuclei become 

 elongated and spindle-shaped, they arrange themselves parallel to one 

 another, and end anteriorly in a short, and posteriorly in a longer 

 thread. 



The germinal rudiment appears at a very early stage (see 2 above), 

 when the division into four follicles has just commenced. In much 

 older organs the whole series of developmental stages can be traced. 

 The centre of the undifferentiated rudiment is occupied by a granular 

 fluid ; the granules increase in size towards the periphery ; in the 

 marginal portion a few, ill-defined nuclei appear, which look as if 

 composed of a large number of granules. A layer of protoplasm 

 6urrouuds the germinal rudiment, and in this cells are differentiated. 

 Nuclei may be observed to originate within the central mass, and the 

 various stages of sperm-development are grouped in concentric suc- 

 cession round this centre. The rudiment may, in fact, be considered 

 as a giant cell in which the nuclear substance is distributed throughout 

 the cell, and gives rise here and there to young nuclei. 



Development of efferent ducts and vesiculse seminales. — The efferent 

 ducts first appear at the posterior end of the rudimentary testes, as a 

 direct prolongation composed of definitely arranged regular cells. 

 At a later stage the recipient duct is seen as a cylindrical strand, 

 without a lumen, extending nearly the length of a segment, and ending 

 in the fatty body. The development in the caterpillar exhibits a 

 very slow increase in breadth and length, and the gradual appearance 

 of a lumen from before backwards. The vesicula appears as a simple 

 swelling of the vas deferens. 



The penis and ductus ejaculatorius first appear in the chrysalis, 

 and are entirely of ectodermic origin. Below the rectum the external 

 epithelium forms a shallow annular depression which gradually 

 becomes deeper. The penis appears as a cylindrical structure raised 

 fruin the bottom of the depression. The invagination deepens and 

 spreads in a dorso-ventral direction, divides into two portions — one 

 ventral, forming the penis proper, the other dorsal, forming the 

 ejaculatory duct. 



Odoriferous Apparatus of Butterflies.* — Dr. E. Haase discusses 

 the various kinds of odours emitted by butterflies. Among those 

 which are shared by both sexes, he distinguishes (1) those which 

 depend on some definite ethereal oil resulting from the food of the 

 caterpillar ; (2) protective odours which are emitted as a protection 

 against enemies. The odours restricted to one sex are the various at- 

 tracting and captivating smells of sexually mature males and females. 

 The latter is illustrated, for instance, by Bombycida, where the odour 

 attracts males from a great distance. Without their olfactory antennas 

 the males cannot discover the females. The males are odoriferous 

 only when the female is capable of flight. The fragrance is very 



* SB. Naturf. GeeelL Job, 1886, pp. 9-10. 



