Descriptions of new Metanemerteans. 9 



wider than neck, rounded anteriorly (Fig. 13). I have seen indivi- 

 duals of about 20 mm in length, but this species probably grows to 

 a still greater size, since I obtained no fully mature specimens; 

 width 1,5 to 2 mm: this species must accordingly be classed in the 

 category of the relatively short and stocky Ämphiporus-sipecies. It 

 is of greater diameter posteriorly. Very contractile. In its appearance, 

 it reminds one of a leech, rather than a Nemertean. 



Ocelli, about 10 or 12 on each side of the head, of large size 

 (Fig. 13), though the ocelli may vary in dimensions in the same in- 

 dividual. They are arranged in an irregulär row along the margin 

 of the head, on each side, but do not reach the brain. The three 

 posterior ocelli, behind the cephalic cleft, often form an oblique row 

 on each side, directed backwards and inwards ; but these oblique lines 

 are not as marked as in Ä. greenmani. 



I found this species abundant at Wood's Holl, in the so-called 

 "Eel Pond", a small inlet of the sea, which has a depth of water of 

 only 2 or 3 feet at low tide, and in which sea-weeds and eel-grass 

 is abundant. 



5. TetrasteTnma clegans Verr. 



The Oesophagus opens into the rhynchodaeum. The intestinal 

 coeca reach to the dorsal surface of the dorsal brain lobe. 



The lateral nerve chords commissure posteriorly above the in- 

 testine. 



Sensory hairs are absent in the snout, but present on the posterior 

 end of the body. There is a yellowish-brown pigment in the inter- 

 stitial tissue, but none in the supporting cells of the body epithelium. 



The rhynchocoel does not extend quite to the posterior end of 

 the body, but terminates about y^jj in anterior to it. There are 10 

 proboscideal nerves. The central stilet is about equal in length to 

 its basis, the latter is rounded posteriorly, without a medial con- 

 striction. 



Sexes separate. The gonads are situated both above and below 

 the nerve chords; there are from 1 to 4 ova in each ovary. 



Length to about 15 mm. Distance between the anterior and 

 posterior eyes about equal to that separating two eyes of one side; 

 the anterior eyes nearer, together, than the posterior. Head rounded, 

 noticeably wider than the neck. 



The characteristic coloration of this species is due to the pre- 

 sence ot ^wo reddish-brown pigment bands, parallel in position, each 



