coe: nemerteans of west and northwest coasts. 293 



above, these woi-ms are very hardy, moving about actively for sev- 

 eral hoars after the pigmented integument has been sloughed off. 

 When placed in fornuilin they do not break up spontaneously, but 

 usually die intact and well extended. 



77. Tetrastemma bicolor Coe. 



Proc. Wash. Acad. Sci., 3, p. 57, PI. 1, fig. 6, 1901 ; Harriman 

 Alaska Expedition, 11, p. 57, 1904. 



This strikingly colored nemertean presents the following peculi- 

 arities of appearance and structure : — 



Body moderately slender, somewhat rounded throughout ; of 

 larger size than many forms of the genus, attaining a length of 

 50-60 mm. when well extended. Ocelli rather large, arranged in 

 the form of a square. 



Color bright brownish red or orange on dorsal surface, with nar- 

 row, sharply marked, median white stripe extending whole length 

 of body; ventral surface gray or whitish. Anterior and lateral 

 margins of head and lateral margins of body for a short distance 

 back of head of same color as ventral surface. 



Blood vessels conspicuous because of deep red color of corpuscles. 



Proboscis rather large ; basis of central stylet somewhat conical, 

 swollen posteriorly, about .075 mm. in length, and about one and 

 one half times as long as stylet itself. The two pouches of acces- 

 sory stylets commonly contain thi'ee or four stylets each. 



Habitat. — Known only from Kadiak, Alaska, occurring in about 

 3 fms. (Coe, :01). The species resembles some varieties of T. ver- 

 miculus Quatr., but lacks the dark jjigment between the two ocelli 

 of the same side which is found in the latter species, and has the 

 median white stripe very sharp and conspicuous. 



78. Tetrastemma aberrans Coe. 



Proc. Wash. Acad. 8ci., 3, p. 58, 1901; Harriman Alaska Expedi- 

 tion, 11, p. 58, 1904. 



PI. 22, fig. ir,o. 



This is a very minute species, individuals seldom exceeding 12 

 mm. in length ; body moderately slender. 



