30 COE 



in length in moderate extension, and ratner slender. The color was 

 olive-green both above and below. A coating of brown particles was 

 sometimes scattered over the dorsal surface. The proboscis is pale. 



Proboscis. — The proboscis sheath extends to posterior end of body ; 

 the proboscis extends only about half way to posterior extremity. The 

 central stylet is remarkably short and blunt. Its basis (p1. vii, fig. i) 

 is at least twice, and often three times, as long as the stylet itself, and 

 is massive in proportions. Its diameter is nearly constant throughout 

 its length, although it is narrowed in front and constricted slightly at 

 about three-fourths the distance towards its posterior end. The pos- 

 terior extremity is sharply truncate or concave and often shows serrated 

 edges (p1. vii, fig. i). There are two lateral pouches of accessory 

 stylets, and each usually contains five stylets similar in size and shape 

 to the central stylet. The character of these remarkably stubby stylets 

 is shown in p1. vii, figures \a and \b. 



The lateral stylet pouches are imbedded in a thickened glandular 

 wreath, yellowish in color, which lies around the circumference of the 

 proboscis in front of the stylet. The mass of muscular tissue surround- 

 ing the basis of the central stylet is unusually thickened, and this ne- 

 cessitates an unusually long canal leading from the posterior chamber 

 to the stylet region. In each of the two specimens sectioned the pro- 

 boscis was provided with 12 nerves. 



Cerebral sense organs. — Situated immediately in front of brain, 

 but in the ventral portion of the head. The canals leading to the ex- 

 terior pass obliquely forward and downward, and open on the anterc 

 ventral surface near the tip of the snout. 



Nephridia. — The nephridia extend from a point immediately in 

 front of the brain backward throughout nearly the whole length of the 

 esophagal region. There is a single pair of efferent ducts situated in 

 the region of the brain, and opening to the exterior on the ventro- 

 lateral aspects of the body. In the specimens examined one of these 

 ducts lay as far forward as the ventral commissure of the brain, while 

 the other was situated opposite the posterior end of the ventral brain- 

 lobe. 



Montgomery^ mentions for Z. virescens that the superficial epithelium 

 of the body contains numerous yellowish, sickle-shaped bodies situated 

 among the epithelial cells. These also occur in Z. thalasshia, but 

 here they are of various sizes, and differ greatly in shape. Some are 

 sickle-shaped, others are rod-like or irregular in form, and have every 

 appearance of having been formed in the gland cells of the epithelium, 



^Zool. Jahrb., x, p. 2, 1S97. 



