103 ILLIXOIS BIOLOGICAL MONOGRAPHS [388 



EXPLANATION OF PLATE 



COTYLASPIS COKERI (EXCEPT FlGURE 56) 



Fig. 53. Sagittal section thru the anterior end of body showing musculature, di- 

 gestive and reproductive organs. X 200. 



Fig. 54. Frontal section thru the openings of the genital pores. X 85. 



Fig. 55. Section thru a marginal organ ; a muscle fiber is seen at the left of the 

 figure and on the other side a nerve fibril passes to the inner end of 

 the thick walled part of the canal. In this section the canal is cut 

 across and can not be traced from the bulb to the exterior. X 580. 



Fig. 56. Section thru a marginal organ in Cotylaspis insignis. X 580. 



Fig. 57. Frontal section thru the adhesive disc showing arrangement of muscula- 

 ture. X 95- 



Fig. 58. Section thru the anterior part of the forebody showing the base of the 

 mouth funnel, anterior part of the pharynx, nerve commissure and 

 eye spots. X 800. 



