BRYOZOA OF THE PHILIPPINE REGION 105 



Measurements. — 



~ [^0 = 0.35-0.45 mm. „ [Lz = 0.60-0.65 mm. 



Opcsium [ h = Q 22 _ Q 3Q mm Zooecium j^ _ Q 25 _ Q AQ mm 



Structure. — The distal portion of the mural rim is a special smooth 

 piece crowning the zooecium. The pivot of the distal avicularium is 

 indicated by two denticles very visible but difficult to illuminate for 

 photography. The mandible is long arched, setiform, winged. 



"Dietellae extremely conspicuous and about four in the distal half 

 of the lateral wall, their openings to the zooecia often large" (Harmer, 

 1926). 



The ovicell is here very small, little salient, somewhat convex, 

 transverse, smooth. The opesium is finely crenulated. 



Harmer found an embryo in the zooecial cavity and placed in an 

 ovisac. The ovicell shelters the embryo, therefore, only at the 

 moment of escape. 



Harmer described a vibraculum but he distinctly figures a setiform 

 (vibraculoid) avicularium. 



Affinities. — This species differs from Ellisina philippinensis in its 

 greater micrometric dimensions (L2>0.50 mm.), in its denticulated 

 opesium, in its mural rim not enlarged at the base, and in its mandible. 



In introducing this species in Setosellina Calvet, 1907, Harmer 

 wrote (p. 264) "As originally introduced, Setosellina so named from 

 its resemblance to the microporoid Setosella, Hincks, was defined as 

 having the main axis of its vibracular opesia in the same line as that 

 of the zooecium. I think it necessary to modify this part of the 

 diagnosis in order to include Membranipora coronata." This modifi- 

 cation is not possible, and is not reasonable moreover, because the 

 genotype, S. roulei is still imperfectly known. Norman having 

 classed M. coronata in Ellisina it is preferable to leave it there 

 provisionally. 



Evidently Ellisina (as the Coronata group of Waters, 1898) is a 

 genus not appearing to have a great constancy even in its definition. 

 Most of the species introduced by simple appearance are imperfectly 

 studied and their essential organs (ovicells, avicularia, ancestrula) 

 are not even figured. It is for this reason that Waters, 1904 (p. 31), 

 wrote "There are several species of Membranipora with oval zooecia 

 and an avicularium at the distal end and this group is a difficult one 

 on account of the few characters available." 



We could separate a special group having an endozooecial ovicell 

 and a vibraculoid (setiform) distal avicularium composed of Ellisina 

 coronata Hincks, 1881, E. philippinensis, new species, E. lajra and E. 

 brevis Canu and Bassler, 1920, for which we might propose a special 

 genus, clearly equatorial but it is absolutely necessary that the other 

 species of Ellisina be better studied and known. 



