396 TRICOMA AND OTHER NEW NEMATODE GENERA, 



half turn in the middle part of its body presents the whole of the 

 head and neck reversed, — what is dorsal appearing ventral. The 

 only way of discovering this distortion is by carefully following 

 up the lateral fields ; the twist in the body will then be discovered. 

 In all cases, therefore, where such an anomaly as a ventral tooth 

 appears, care should be exercised before coming to a decision as 

 to the actual facts of the case. I did not discover the position 

 or nature of the lateral organs. The eyes, or rather eye-spots, 

 are situated in the oesophagus at a distance from the anterior 

 extremity twice as great as the width of the head. There is a 

 distinct tendency toward a dorsal agglomeration of the yellowish- 

 brown pigment of which the spots are composed, and to a dorso- 

 ventral division of the dorsal part into halves. The ventral 

 pigment consists of a narrow yellowish streak of the same length 

 as the large dorsal mass, namely, a length equal to half the width 

 of the head. There is no distinct refractive body connected with 

 the eye-spots. The oesophagus expands slightly to receive the 

 pharynx, and thence to the posterior bulb measures one-third as 

 wide as the neck ; the bulb is prolate, measures four-fifths as 

 wide as the base of the neck, and presents a distinct and extensive 

 internal chitinous lining for the attachment of its powerful radial 

 muscles. These latter are very effectual in exerting suction. I 

 remember to have seen a Chromadora seize on to the surface of 

 one of my glass object-slides with its mouth and move its tail up 

 near to the head, when the caudal spinneret came into play and 

 secured a hold; then, releasing the head, the little animal proceeded 

 to execute a movement similar to that made by the larvae of the 

 Geometrid moths, by reaching forward and again seizing on to 

 the face of the glass with its mouth and again drawing forward 

 its tail. Of course nothing but suction could have so attached 

 the mouth of the worm to the smooth surface of glass. The 

 oesophagus is separated from the intestine by a deep and conspi- 

 cuous constriction. The granular intestine is two-thirds as wide 

 as the body and is of a yellowish colour, being composed of cells 

 of such a size that nine of them make up a circumference. The 

 rectum is situated at an angle of forty-five degrees with the axis of 



