■200 bulletin: museum of compaeative zoology. 



nephridia are particularly interesting in that they seem to represent 

 a very primitive condition, such as is found in the planarians. 



Sense organs. — Frontal sense organs highly specialized ; cerebral 

 sense organs as in related species ; cephalic furrows long and deep, 

 widely expanded posteriorly. 



Reproductive organs. — Sexually mature in July. Ova develop 

 ■on narrow stalks attached to wall of ovary and later break off and 

 fall into the OA^arian cavity, as Wilson (:00, p. 123) has described for 

 Cerehratulus lacteus. 



Habitat.— The species is known only from Yakutat, Alaska, 

 where it occurs under stones at low water, but is not common. 



38. Cerebratulus montgomeryi Coe. 



Proc. Wash. Acad. Sci., 3, p. 80, PI. 6, figs. 1, 2, 1901 ; Harriman 

 Alaska Expedition, 11, p. 80, 1904. 



PI. 3, figs. 38, 39. . 



This very large and brilliantly colored nemertean occurs abun- 

 dantly along the whole Pacific coast of Alaska and in the Bering 

 Sea, and may be easily recognized by the following ^peculiarities : 

 Body large, very long and ribbon-like when well extended, nuich flat- 

 tened except in esophageal region ; head rounded and obtuse or 

 pear-shaped and acutely pointed according to state of contraction ; 

 cephalic furrows moderately long ; ocelli wanting. 



Length commonly 50 cm. to two meters ; occasionally up to two 

 and a half or three meters when fully extended ; width 8 to 17 mm. 



Color. — Bright blood red throughout body, except tip of snout, 

 which is white or yellowish white both above and below (PI. 3, 

 figs. 38, 39). 



Proboscis pale red, of moderate size, inner longitudinal muscles 

 wanting. Cephalic glands well developed. Nephridia limited to 

 anterior half of esophageal region, with a single pair of efferent 

 ducts at posterior end. 



Habitat. — This magnificent s})ecies has already been recorded 

 from Puget Sound, and from various localities along the Alaska 

 coast to the Aleutian Islands (Coe, : 01, p. 82), where it is common 

 in muddy locations, beneath stones near low water mark. 



