266 



BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



Habitat. — Dredged in about 50 fms. off San Pedro, California ; 

 also on piles of wharf, San Diego Harbor, California. Not com- 

 mon. 



65. Amphiporus macracanthus, sp. nov. 

 PI. 24, fig. 193; PI. 25, fig. '200; Text-fig. 55. 



This species is in certain respects the most remarkable of the 

 numerous forms of this genus which occur in the region included in 

 this report. 



The size of basis of central stylet of proboscis far exceeds that of 

 any other species of the genus, or, indeed, of any other nemertean. 



The basis alone measures more than a 

 millimeter in length in some specimens, 

 being actually one eighteenth as long 

 as the whole body of the animal when 

 contracted. 



Body short, thick, rounded, and larg- 

 est anteriorly when contracted. General 

 shape of preserved specimens much like 

 similar small specimens of A. angulatus, 

 but appearance in life unknown. 



Length of preserved specimens 14 to 

 25 mm. 



Color in life not recorded, and is not 

 retained in the alcoholic material. 



Proboscis. — Of remarkably large 

 size, with a short posterior chamber. 

 It is provided with 10 large nerves. 

 Proboscis sheath extends quite to pos- 

 terior extremity of body. Armature 

 especially remarkable because of com- 

 paratively enormous size of basis of cen- 

 tral stylet, which sometimes becomes 

 more than a millimeter in length (PI. 

 25, fig. 200). In a worm measuring 15 

 mm. after preservation the basis is 0.85 

 mm. long and 0.25 mm. broad in its 

 The basis alone is therefore about one eighteenth 



Fig. 55. — Amphiporus macracan- 

 thus. Outline of central stylets 

 and bases. The one at the left 

 from Wainwright Inlet, Alaska, 

 the other from Cape Smyth, 

 Alaska, x 62. 



wddest portion. 



