20 TERETXJLARIA. 



front ; eyes near the front, but not marginal. Length 13'" ; breadth 

 scarcely ^"'. 



Vermiculus lineatus, Dalyell, Pow. Great, ii. 90. pi. 10. f. 19, 20. 

 II ab. Coast of Scotland, Dalyell. 



2. C? flustrse, filiform, acute at both ends, pellucid, dark-grey or 

 brownish, with a darker line in front ; eyes black, placed on a 

 pellucid portion in front. Length ^"'. 



Ascaris flustrae, Dalyell, Pow. Creat. ii. 92. pi. 10. f. 27. 



Hab. Coast of Scotland amongst Flustrae, Dalyell. 



14. TETRASTEmiULA, Ehrenberff, 1831. 

 Tetrastemma, Oersted, Entw. Plattw. 84. Dies. Syst. Helm. i. 256. 

 Char. Acephalous, the body linear-elongate, flattish, with four 

 eyes placed in a quadrangle in fi'ont : mouth terminal. 



1 . T. varicolor, body rounded in front, tapered at the tail ; eyes in 

 a square ; the front unspotted. Length 10-1.5'"; breadth 1"'. 



Var. a. cream -yellow. 



Var. /3. punctulated with black. 



Var. y. olivaceous. 



Planaria quadrioculata, Johnston in Zool. Journ. iv. 56. 



Nemertes quadrioculata, Johnston in Mag. Zool. ^ Bot.i. 535. pi. 17. 



f. 4. 

 Prostoma quadrioculata, Johnston in Ann. ^ Mag. Nat. Hist. xvi. 436. 

 Folia quadrioculata, Quatrefages in Voy. en Sicile, ii. 128. pi. 16. f. 10. 

 Tetrastemma varicolor, Oersted, Entw. Plattw, 85. f. 41-44. Dies. 



Syst. Helm. i. 257. 



Hab. The shore between tide-marks. 



2. T. variegatum, cylindrical, rather obtuse at both ends, variegated 

 red and white, with a white line down the back. Length 8'" ; 

 breadth i"'. 



Vermiculus variegatus, Dalyell, Pow. Creat. ii. 91. pi. 10. f. 25, 26. 

 Hab. Shores of Scotland, rare, Dalyell. 



3. T.? algae, linear-elongate, widest in front, siskin-green tending to 

 yellow or to brown. Length 4"' ; breadth ^"'. 



Planaria algae, Dalyell, Pow. Creat. ii. 117. pi- 16. f. 24, 25. 

 Hab. Among marine algae, Dalyell. 

 Obs. The motion is very swift. 



