114 BIOLOGICAL SOCIETY OF WASHINGTON. 



composed of deep cylindrical gastropores vertically grooved for 

 three to six dactylopores, which are wholly continuous with the 

 cavity of the gastropore. Ampullae not noticed. Diameter of the 

 calyx about 0.$**., of the gastropore proper about o.35 mm . ; average 

 distance between the calyces, o.'j-i.f *. 



Gastropores deep, cylindrical, with a short, hardly perceptible 

 style, which comes into the bottom of the gastropore, but, as a ver 

 tical section shows, not vertically but obliquely from one side. 

 Inner surface nearly smooth, a narrow elevated ridge bounding the 

 margin of the combined gastropores and dactylopores. 



Dactyloporic grooves rather shallow, long, each with an evanes 

 cent trace of a style on the outer wall ; six seems to be the normal 

 number to each calyx. 



General surface spiculose or finely granulated with small, pointed 

 granules, with regularly-shaped, elevated, uniform papillae stand 

 ing in the spaces between the pore margins, and rising to about 

 the same height, but absent on the immature growing margin of 

 the colony. 



Coenosteum less vesicular than in the previously-described forms. 

 Soft parts unknown. Habitat : on the outside of a living Mytilus 

 californianuS) from six fathoms, Coal Harbor, Unga Island, Shuma- 

 gin Islands; collected October, 1874, by W. H. Dall. Museum 

 number, 6852. 



Errina Pourtalesii, n. s. 



Coenosteum of a saccharine structure, rising in stout, subcylin- 

 drical, rather round-pointed, occasionally branching stems ten to 

 fifty millimeters high (possibly much larger at times), and eight or 

 more in diameter ; color, when fresh, deep rose-red, bleaching to 

 white or gray in dead specimens ; surface loosely granular, becom 

 ing lighter colored and more compact inward toward the central 

 axis ; gastropores disposed in irregular lines, which, in the specimen 

 in hand, have a tendency to run from the base spirally to the left, 

 around the column, but are so crowded that little of the surface is 

 free from the nariform hoods of the attendant dactylopores ; the 



