50 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



nition." In the meantime Canu and Bassler (1933:18) mistakenly re- 

 named the genus Ellisinidra with levata Hincks as the genotype. These 

 authors apparently did not examine material of levata since they indicate 

 that the "ovicell is hyperstomial." 



The avicularia are definitely members of a zooecial series, each one 

 arising at the distal end of the preceding zooecium. This is clearly shown 

 at the margin of the zoarium where a complete zooecium is followed by 

 a developing avicularian chamber. Avicularia are usually present distal 

 to the zooecia but they are sometimes absent and the latter condition 

 seems to negate the supposition of Canu and Bassler that "they are neces- 

 sary in the opening of the opercular valve." 



ElHsina levata (Hincks), 1882 

 Plate 4, fig. 4 



Membranipora levata Hincks, 1882:249; 1884:10. 

 Ellisinidra levata, Canu and Bassler, 1933 :18. 

 ElHsina levata, Hastings, 1945:87. 



Zoarium encrusting, smooth, white. Zooecia of moderate size (length 

 0.40 to 0.53 mm and width 0.25 to 0.30 mm), very distinct with broad 

 separating grooves. Gymnocyst small and smooth, cryptocyst narrow, thin 

 and slightly granulated. Opesia oval or elliptical, occupying nearly all 

 of the frontal area, the walls thin and the mural rim smooth, no spines. 

 Pore chambers present. The avicularia are interzooecial, the chambers 

 go down to the level of the dorsal side and each chamber has a large 

 distal pore connecting with the next distal zooecium. The chamber is 

 more or less square (0.10 to 0.13 mm in either dimension), the aviculari- 

 um mounted near the middle of the frontal surface, the rostrum elevated 

 and the triangular mandible directed transversely (with some variation). 



According to Hastings, who has examined the type material, the ovi- 

 cell is endozooecial and embedded in a kenozooecium (avicularian cham- 

 ber without an avicularium), and is closed by the zooecial operculum. 



While this species has been the subject of so much discussion, it ap- 

 parently has been known only from Hincks' material, "Houston Stewart 

 Channel, 15-20 fathoms; Cumshewa; very abundant," British Columbia. 



Hancock Station 1064, off Santa Barbara Island, California, 27 fms, 

 one colony on a shell, not in reproduction. 



