330 ERNEST WARREN. 



In PI. XIX, figs. 69-72, a series of transverse sections, cut 

 from behind forwards, is given, showing the relationship of 

 the chitinous tube to its sheath. Internally the chitinous 

 tube is lined by liypodennis continuous round the edge of the 

 foramen with the general hypodermis of the sheath (fig. 70, e. c), 

 which, owing to the development of muscle, is greatly inter- 

 rupted. In fig. 71 the entrance of the ejaculatory duct 

 through the foramen is shown. The wall of the sheath is 

 highly muscular, consisting largely of longitudinally arranged 

 fibres. At the anterior end of the chitinous penis there is a 

 thick mass of muscle, and just in front of the plane passing- 

 through the maximum diameter of the sAvelling of the tube 

 there are some well-marked oblique and transverse bands of 

 muscle (fig. 70, t. m.). By the contraction of these various 

 systems of muscles the genital apparatus is squeezed out 

 during copulation. 



Female. — The vagina is a long convoluted tube extending 

 forwards venti-ally to abdominal segment Yl. Internally it 

 is lined by cuticle, while on the outside there is an ex- 

 ceptionally powerful sheath of muscle-fibres. Anteriorly the 

 vagina receives two thin-walled oviducts ; the left extends 

 forwards, while the right one appears to be branched, one 

 limb extending forwards and the other backwards (PI. XX, 

 fig. 75). These thin-walled oviducts bear a number of very 

 short ovarian tubes, consisting of one or two pairs of elements. 

 There seem to be six tubes associated with each oviduct, but 

 it was not possible with the available material to be certain 

 with regard to the number. A pair of elements consists of 

 a distal mass of nutritive cells and a proximal ovum (figs. 76 

 and 77). The ovarian tubes are in very different stages of 

 development at any one time. The eggs grow to a great 

 size ; at first, when the egg is small or of medium size, the 

 protoplasm is granular and does not carry 3'olk-globules, but 

 later a dense mass of large globules is produced. The nucleus 

 of the egg becomes distinctly stellate. As the egg matures 

 the nutritive tissue dwindles, and ultimately it forms a little 

 mass of cells attached to the distal end. It is probable that 



