142 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Measurements. — 



~ |7io = 0.10 mm. „ . JZ3 = 0.90 mm. 



Opesium, Zooeciai, on 



lw = 0.15mm. U2 = 0.30mm. 



Affinities. — This species is very close to Microporina borealis Smitt 

 1867, but differs from it only in its smaller opesium and in its smaller 

 zooecia (0.30 and not 0.40 mm.). It differs from Microporina 

 elongata Hincks, 1881, in its large and non oblique avicularia. The 

 longitudinal section shows that the avicularium is independent of the 

 two zooecia between which it is placed. 



Microporina is a genus of the northern portion of the temperate 

 zone. Our very numerous specimens were all dead. 



Occurrence.— D. 4807. Cape Tsiuka, Sea of Japan; 41° 36' 12" 

 N.; 140° 36' E. 



Cotypes.— Cat. No. 8349, U.S.N.M. 



Genus CUPULARIA Lamouroux, 1821 



CUPULARIA UMBELLATA Defrance, 1823 



Plate 15, figs. 5-11 



1907. Cupularia utnbellata Calvet, Expeditions scientifique du Travailleur et du 



Talisman, p. 393. 

 1921. Cupularia umbellata Waters, Observations upon the relationships of the 



(Bryozoa) Selenariidae, etc., fossil and recent. Linnean Society's 



Journal, Zoology, vol. 34, p. 414 (not synonymy). 

 1923. Cupularia umbellata Canu and Bassler, North American Later Tertiary 



and Quaternary Bryozoa, Bull. 125, U. S. National Museum, pp. 76, 



80, pi. 2, figs. 15-19 (bibliography, occurrence). 



We are not in accord at all with Waters on the synonymy of the 

 various species of Cupularia. He compares notably Cupularia liaidin- 

 geri Reuss, 1847, with the present species; but the fossil is absolutely 

 distinct and very well characterized by its spicules never united. 

 This beautiful species has never been noted in the Pacific; it is prob- 

 able that it is necessary to refer to it the species figured by Miss 

 Robertson and to which we have given the name of Cupularia robert- 

 soniae, our material for study being insufficient. 



Waters ranges in Cupularia lowei Busk, 1859, all the irregular 

 zoaria, more or less lobed. We did not believe that this difference 

 is distinctly specific. 



Structure. — The operculum is detachable; its proximal border is 

 straight or concave. The cilium of the vibraculum is falciform; its 

 articulation resembles somewhat that of the avicularia. Viewed 

 on the interior and by transparency, the frontal is perforated later- 

 ally by the opesiules and in the middle by small irregularly arranged 

 pores; the union of the lateral spicules is therefore not complete. 



The tangential section through the interior face shows well the 

 small pores discovered by Waters, 1921, which serve as passages 

 for the zoarial hydrostatic muscles. 



