630 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



tubes are isolated from each other. No adventitious tubes." (Canu and 

 Bassler, 1922:26). Genotype, Tubulipora patina Lamarck, 1816. 



The above description, drav^^n from P. patina and correct for that 

 species, requires some modification as the ovicells are not always much 

 expanded laterally and sometimes in other species may even be longer 

 than broad. The ovicells are symmetrically developed and the ooeciostome 

 is terminal in the midline at or near the distal border and the ooecial 

 expansion is not continued beyond it. The inflation often surrounds one 

 or more, sometimes several, peristomes; even in the same species the 

 shape of the ovicell and the number of the included peristomes may vary 

 considerably due to the amount of lateral expansion. There is much 

 closure of the older peristomes by a calcified membrane which is either 

 perforated by a number of small pores, or provided with a small erect 

 central tubular pore. 



The zoarium is usually adnate, but may be erect or semierect and 

 more or less contorted and either unilaminar or bilaminate. 



Key TO THE Species of Plagioecia 



1. Zoarium more or less free, erect or semierect 2 



Zoarium entirely adnate or sometimes free at the edges ... 4 



2. Zoarium with narrow, bilaminate, contorted branches which 



form a free reticulum meandrina 



Zoarium with broad bilaminate lobes, contorted 3 



3. Zoarium erect from a rather narrow base, sometimes stipitate, 



contorted, the folds thicker than in other species . . grimaldii 

 Zoarium beginning with a broad adnate base from which erect, 

 contorted folds arise, much thinner than in P. grimaldii . . . 



tortuosa 



4. Except near the center of the zoarium the peristomes are in 



uniserial, radiating rows, connate only at the base . anacapensis 

 Peristomes not in radiating series 5 



5. Zoarium broad and thin, irregular, with occasional smooth 



areas containing aborted tubules without apertures; peri- 

 stomes very short; ovicell low and flat, surrounding a few 



peristomes, irregularly rounded tubiabortiva 



Zoarium rounded or with flabellate lobes, ovicell conspicuous 



and usually transverse 6 



6. Ovicell usually several times as broad as long and slightly 



arcuate to conform to the zoarial border, the lateral ends 



often enclosing peristomes patina 



Ovicell narrower, sometimes nearly round 7 



