642 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Key to the Species of Diaperoecia 



1. Slender, erect or semierect, branching species, rising from a 



small encrusting base, ooeciostome free 2 



Adnate species, with expanded lobes, the lobes sometimes short- 

 erect, ooeciostome at the side of a peristome 3 



2. Branches very narrow, seldom as much as 1.0 mm in width, 



apertures of peristomes about 0.13 mm in width . . floridana 

 Branches wider, 2 mm or more, apertures of peristomes 0.20 

 mm or more, the lateral peristomes usually in short connate 

 series californica 



3. Zoarium adnate and branched laterally, with short, erect 



fertile branches which expand into small capitula con- 

 taining the ovicell intermedia 



Fertile lobes adnate 4 



4. Fertile lobes flabellate, usually more or less triangular, 



peristomes projecting high above the ovicell .... johnstoni 

 Fertile lobe rounded, peristomes projecting only slightly 



above the ovicell claviformis 



Diaperoecia californica (d'Orbigny), 1852 

 Plate 67, figs. 1 and 2 



Idmonea Californica d'Orbigny, 1853:732. 

 Idmonea Californica, Conrad, 1855:441. 

 Idmonea californica, Gabb and Horn, 1862:168. 

 Tubulipora dawsoni, Hinclcs, 1884:205. 

 Idmonea californica, Robertson, 1910:253. 

 Idmonea californica, Canu and Bassler, 1923:199. 

 Idmonea californica, O'Donoghue, 1923:12; 1926:27. 

 Idmonea palmata, O'Donoghue, 1923:12. 

 Diaperoecia intricata, Canu and Bassler, 1928:41. 



The zoarium is composed of erect or spreading branches which fre- 

 quently reach a height of 25 mm and occasionally as much as 50 mm. 

 The branches may anastomose and often form reticulated masses. 

 Usually, in deeper water, the branches are narrow in proportion to their 

 length, 2 to 3 mm in breadth, but in exposed places along shore the 

 zoarium is more consolidated and the branches shorter and wider and 

 less erect {Idmonea palmata O'Donoghue) ; sometimes procumbent and 

 attached to the substratum by the radicles {Diaperoecia intricata, Canu 

 and Bassler, 1927:41). Radicles or supporting processes are frequently 



