NO. 2 OSBURN: EASTERN PACIFIC BRYOZOA — CHEILOSTOMATA 429 



Recorded by Nordgaard from several places in the Greenland area, 

 and from Iceland bj'^ Hincks. 



Point Barrow, Alaska, 25 fms, Arctic Research Laboratory, G. E. 

 MacGinitie, collector. Also a specimen from Tuan Island, Pavlof Bay, 

 Alaska. 



Rhamphostomella spinigera Lorenz, 1886 

 Plate 51, fig. 1 



Rhamphostomella spinigera Lorenz, 1886 :12. 

 Rhamphostomella spinigera, Nordgaard, 1906:32. 

 Discopora plicata var. spinigera, Levinsen, 1916:460. 

 Rhamphostomella spinigera, Osburn, 1936:542. 



Zoarium encrusting. Zooecia moderate in size, 0.60 to 0.70 mm 

 long by about 0.40 mm wide, distinct with deep separating grooves; 

 the front somewhat inflated, smooth with delicate reticulations, with 

 a row of areolar pores between which short costae reach only to the 

 edge of the frontal wall. The primary aperture is rounded, 0.22 mm 

 wide by 0.20 long, the proximal border bisinuate, with a cardelle at 

 each end and a median lyrula which is usually expanded at the tip. 

 The peristome is thin, elevated into a lappet opposite the avicularian 

 umbo, and with about 4 oral spines which are rather evanescent. The 

 avicularian chamber is moderate in size and rarely extends past the 

 midline of the front, the rostrum narrow and high and bearing on its 

 lateral surface an elongate avicularium with a spatulate mandible. 

 Opposite tiie rostrum is a small lappet of the peristome and the form 

 of the secondary aperture is more or less angulated proximally and 

 rounded distally. 



The ovicell is hemispherical and conspicuous, often slightly longer 

 than wide (0.30 mm wide by 0.30 to 0.35 mm long), with small pores. 

 One pair of oral spines is often involved in the proximal corners of the 

 ooecium. 



Described from Jan Mayen, and listed by Nordgaard, Levinsen and 

 Osburn from Greenland. 



Canoe Bay, Alaska, U. S. Alaska Crab Investigation, Sta. C. 160-41, 

 28 fms ; and Point Barrow, Alaska, Arctic Research Laboratory, G. E. 

 MacGinitie, collector, 18 fms. 



