SO ILLINOIS BIOLOGICAL MONOGRAPHS [330 



COTYLASPIS COKERI Barker and Parsons 1914 

 [Figures 46 to 55, 57, 58] 



From four to twenty-five specimens were found in the intestine 

 of each of seven specimens of Malacoclemmys lesucurii from Newton, 

 Texas. 



The worms (Figs. 46, 47, 52) average 1.5 mm. in length by 0.7 

 mm. in width, altho there is considerable variation in relative length 

 and width due to the movements of the animal. The body is composed 

 of two parts, an anterior dorsal forebody and a posterior ventral adhe- 

 sive disc. "When extended (Fig. 46), the forebody has the shape of a 

 cornucopia, the larger end attached obliquely to the central two-thirds 

 of the dorsal surface of the adhesive disc. In this condition the worm 

 has an elongate form, projecting beyond the adhesive disc a distance 

 equal to the length of that structure: in a retracted condition (Fig. 52) 

 it is compact and may not project beyond the disc. The total length 

 of the worm varies therefore with the state of extension of the forebody, 

 from the length of the adhesive disc to twice that distance. 



The adhesive disc (Figs. 47, 57) is a muscular organ, a multilocu- 

 late sucker, used for attachment and locomotion. It has a crenate oval 

 outline, the dorsal surface is arched, and the ventral surface is flattened. 

 The ventral surface is divided by two longitudinal and eleven cross 

 ridges into thirty-two acetabula, which are arranged in three rows ; 

 there are twenty-two peripheral alveoli enclosing ten median alveoli. 

 In this statement, the alveolus at either end is counted in the peripheral 

 rather than the median row, tho in location included in both. These 

 compartments change in shape with the movements of the animal, be- 

 coming oval or quadrangular. The shape and size of the disc are rela- 

 tively constant, measurements of the disc in twenty mounted toto speci- 

 mens vary only from 1.2 to 1.4 mm. in length and from 0.58 to 0.78 

 mm. in width. This structure recalls the molluscan foot, and it has 

 often been termed the foot altho the morphological comparison is not 

 precise. 



Movement consists of extension of the forebody, which furthermore 

 may be turned in any direction, and in the less striking and more re- 

 stricted movement of the disc. The disc has a tendency to turn up at 

 the edges, especially at the anterior and posterior ends. In adhesion 

 the organ may act as a unit, or the separate alveoli may function inde- 

 pendently. In locomotion there is a regular series of movements, the 

 forebody is extended and attached by the sucking action of the mouth 

 funnel, then the disc is loosened and the forebody contracted, bringing 

 the anterior part of the disc near the mouth, when the disc is attached 



