26 COE 



Color. The color varies considerably, as will be seen from the two 

 color varieties on pi. n, figs, i and 2. The commonest form is 

 dark velvety-brown above, with a paler median line, much paler and 

 slightly yellowish in front, and flesh-colored or creamy white below. 

 Other individuals have the whole dorsal and lateral surfaces of a mot- 

 tled reddish brown color, with a tinge of purple, while the ventral 

 surface is pale yellow or flesh-colored. Sometimes the head is nearly 

 colorless. The dorsal surface almost always has an appearance sug- 

 gestive of velvet. This color is superficial, and is easily removed by 

 rough handling. 



Proboscis. Proboscis small, very short and delicate, sometimes 

 scarcely more than -Xr the length of body. The proboscis sheath 

 reaches well toward middle of body, but is very small toward its pos- 

 terior end ; in esophagal region it is well developed, with a thick outer 

 layer of circular muscles, and a thin, inner, longitudinal muscular 

 layer. The rhynchodaeum passes backward a considerable distance 

 before the intestinal canal is separated from the proboscis opening. 



The armature of the proboscis consists of a weak central stylet, and 

 a pair of pouches of accessory stylets (p1. viii, fig. i). The basis of 

 the central stylet is rather slender in front, slightly contracted near its 



posterior third, from which point it swells out 

 suddenly into a large spherical bulb. The cen- 

 tral stylet is slightly shorter than its basis. Each 

 of the reserve pouches usually contains three 

 small stylets with swollen bases. The posterior 

 chamber of the proboscis is narrow. The pro- 

 boscis is provided with 1 1 distinct nerves. 



Ocelli. The ocelli are very numerous. On 

 Fig. 4. Empledo- each side of the tip of the snout is an elongated 

 nema burgeri. Dor- c l us ter of minute eyes, all situated near the dor- 



ea sal surface, and without regularity of arrange- 

 show arrangement of . . 



ocelli X 8 ment. Their number is commonly 60 or more 



on each side (fig. 4). Back of these are a few 



other eyes, likewise very minute, situated deep in the tissues of the 



body, and seen only with difficulty. They are scattered irregularly 



from near the lateral borders in front of the brain inward towards the 



median line (fig. 4). 



Cerebral sense organs. Unusually large. They lie lateral to the 



rhynchodEeum, and slightly in front of the brain. The ducts by which 



they communicate with the exterior pass forward to open latero-ven- 



trally. 



