NO. 1788. 



NORTH AMERICAN EROASILID.E— WILSON. 



301 



substance of these cells, and especially the nuclei, stain deeply with 

 hsematoxyiin in strong contrast to the red secretion which fills the 

 lumen of the gland. 



Semen receptacle. — It is impossible to distinguish the semen recep- 

 tacle in the living copepod, since it lies 

 directly above the intestine, is of about 

 the same width as the latter, and its 

 walls are structure- 

 less and as trans- 

 parent as glass. 



In both trans- 

 verse and longi- 

 tudinal sections, 

 however, it stands 

 out prominently. 

 It consists of a 

 cylindrical 

 (fig. 15), ex- 

 tending from the 

 middle of the geni- 

 tal segment for- 

 ward through the 



long 

 bag 



Fig. 22.— Fully matured 

 femaleofErgasiluscen- 



TRAUCniDARUSI, SHOWING 

 RELATIVE SIZE AND SHAPE 

 OF COMPLETED PROCESSES 

 IN DORS\L VIEW. 



free thorax to the 

 posterior border of the first segment. 

 This bag occupies the entire body cavity 

 between the intestine and the dorsal 

 wall of the thorax. It is somewhat 

 narrowed at the center, where it passes 

 the groove between the third and fourth 



thorax segments, and is 



enlarged 



at 



Fig. 21.— The third and fourth oblique 



UTERINE processes, EXTENDING FOR- 

 WARD AND DOWNWARD FROM THE OUTER 

 SIDES OF THE FIRST PROCESSES. ANTE- 

 RIORLY CAN BE SEEN THE FUSED OVARY 

 AND POSTERIORLY THE CEMENT GLANDS. 



either end, more in 



front than posteri- 

 orly. It is very 



nearly the same 



diameter as the 



intestine, being 



w i d e r anteriorly 



(fig. 17). At the 



posterior end it di- 

 vides, or, rather, sends out a tube on either side, 

 which extends around the intestine ventrally 

 and posterior to the genital openings. Each 

 tube then turns forward and opens into the 

 oviduct just before the latter reaches the os 

 opening. This extraordinarily large receptacle is entirely filled 

 with spermatozoa in the living female, but they cling together 

 and shrink away from the wall somewhat in preserved mate- 



Fig.23.— The relative size 

 and shape of completed 

 processes as seen in 

 ventral view. 



uterus or external 



