NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA CYCLOSTOMATA 763 



is large, as much as 0.25 mm in diameter at the base and about half as 

 wide as its distal end, as much as 2 mm long but usually much shorter; 

 flexible and with longitudinal muscles only which do not extend into 

 the calyx. The expanded caljoi is cup-shaped, with the tentacle crown 

 transverse at the top. Spines present on the stalk and calyx, or wanting 

 on one or both of them. Genotype, Brachionus cernuus Pallas, 1771. 



Pedicellina cernua (Pallas), 1771 

 Plate 82, fig. 2 



Brachionus cernuus Pallas, 1771 :57. 

 Pedicellina americana Leidy, 1855:143. 

 Pedicellina nutans, Robertson, 1900:332. 

 Pedicellina echinata, Robertson, 1900:344. 

 Pedicellina cernua, O'Donoghue, 1926:7. 



The stolon is slender, more or less transparent, branching, consisting 

 of an irregular succession of fertile and infertile internodes, the fertile 

 ones shorter than the others, as a rule, and somewhat swollen. The 

 pedicel is broadest at the base, about 0.25 mm in diameter but often 

 smaller, diminishing in size upward to about half of the basal width; 

 thin walled and flexible, with longitudinal muscles which do not enter 

 the calyx. Usually there is a slight constriction between the pedicel and 

 calyx. The pedicel may be 2 mm or more in length but is usually shorter. 



The calyx is cup-shaped with a well-marked gibbosity on the dorsal 

 side, varying greatly in size, in our largest specimens about 0.55 mm 

 long by 0.40 mm in diameter. The lophophore is terminal and transverse, 

 with the tentacle number varying from 14 to 24. 



Spines are sometimes present on the stalk and also on the calyx, and 

 this feature has led to the erection of several species names, P. echinata 

 M. Sars, 1835:5, P. glabra Hincks, 1880:565 and P. hirsuta Jullien, 

 1888:13. However there is so much variation in the presence and dis- 

 tribution of the spines that these must be considered merely nominal 

 varieties. In our material, which extends from British Columbia to 

 southern California, most of the zooecia are without spines, while a 

 few spines occur occasionally even on the same colonies with bare zooecia. 



The species is cosmopolitan. Robertson listed it as P. nutans ( ?) 

 from Yakutat, Alaska, and as echinata from Tomales Bay, California, 

 and O'Donoghue recorded it from several localities in British Columbia. 



Hancock collections: Five Fingers, British Columbia; Tomales Bay 

 and Lime Point, California; and the writer has obtained it at Newport 

 Harbor and La Jolla, southern California. It is a littoral species, usually 

 found on the piles of docks or at low tide. 



