Descriptions of new Metaiieinerteau». 3 



the lateral stilets are contained in the two lateral pockets, usually 

 two stilets in each. In only 1 case (out of at least 100 individuals 

 examined) were 4 lateral pockets present. 



The Oesophagus empties into the rhynchodaeum. The anterior 

 portion of the latter is ciliated, and opens ventrally at the anterior 

 end of the head. 



The two intestinal coeca extend to the dorsal brain lobe. 



The cerebral sense organs are voluminous, and extend to the 

 brain; the ciliated cleft does not extend to the dorsal side of the head. 



A large cephalic gland surrounds the rhynchodaeum, extending 

 posteriorly to the brain. It empties by a considerable number of 

 ducts on the anterior end of the head. 



Sexes separate; the ovaries situated above the nerve chords, 1 

 to 10 ova present in each ovary; the testicles are placed both above 

 and below the nerve chords. 



The ocelli (Figs. 14, 15), as noted above, extend along the nerve 

 chords behind the brain, in the oesophageal region; in very large 

 individuals there may be as many as 12 or 15 in a Single row on 

 each side of the body, behind the brain. These posterior ocelli are 

 absent in very young individuals, and are always smaller than those 

 of the head. There is a considerable number of eyes on the dorsal 

 side of the head, varying, however, not only with age, but also in 

 different individuals of the same size. They are as a rule situated 

 on the margins of the head, as in Fig. 14, about 1 to 3 rows deep 

 on each side; sometimes there is a tendency to the formation of 

 transverse rows of ocelli, as in Fig. 15. 



The color varies from a milky-white or yellowish (as at Wood's 

 Holl) to a pure green (Sea Isle). This species attains a length of 

 40 or 50 mm. In füll extension the head is rounded, considerably 

 wider than the neck; the body becoming very elongated. The body 

 is not flattened, but cylindrical in shape, 



I have found this species at Wood's Holl aud at Sea Isle, on 

 sea-weeds and wooden piers, at about ^ low tide level. At Sea Isle 

 it is more abundant, and reaches a greater length, than at Wood's 

 Holl. 



This new genus Zygonemertes unites characters of Eunemertes 

 and Ämphiporus, whence the application of the name I have given it, 

 which signifies literally "Yoke-Nemertean". It approaches Eunemertes 

 1) in the abbreviation of the proboscis, and in the shape of the basis 

 of the central stilet ; in no other Nemertean does the stilet basis have 



1* 



