302 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



The zoarium encrusts shells and corallines, conspicuous because of 

 its brilliant coloration, orange to very dark red. The zooecia are mod- 

 erately large, 0.60 to 0.80 mm long by 0.45 to 0.60 mm wide, irregu- 

 larly ovoid and distinct with deep separating grooves. The frontal is a 

 thick pleurocyst with about two rows of large areolar pores between 

 which are often strong costal ridges ; in final calcification the pores may 

 be carried up toward the central area, a roughly pointed umbo may 

 be developed and the costal ridges may extend upon it ; there is a thick 

 shining red ectocyst and the color also pervades the skeletal structure. 

 The aperture is elongate, 0.18 to 0.20 mm long by 0.13 to 0.15 mm 

 wide, rounded distally, the sides somewhat parallel; cardelles vary in 

 size, in older zooecia often prominent ; the poster does not always 

 conform to the shape of the operculum and varies from broadly arcuate 

 to deeply sinuate. The operculum is rather strongly chitinized, red in 

 color like the frontal ectocyst, with a strong sclerite which extends half 

 the distance inside of the border beyond the points of attachment; 

 proximal to the cardelles the operculum is small and short, like a semi- 

 circular lobe, thinner and without sclerites and even in dried specimens 

 usually remains attached to the compensation sac. The peristome is low 

 and is usually wanting on the proximal border, with 6 to 8 strong spines. 

 There are conspicuous dietellae. 



Frontal avicularia are often present on some of the zooecia, but 

 may be wanting from the whole colony; the mandible red and elongate, 

 as long as 0.25 mm but usually shorter, the beak somewhat elevated 

 and directed proximally or laterally. 



The ovicell is large, 0.25 mm in either dimension, prominent and 

 slightly embedded, hyperstomial and not closed by the operculum, sur- 

 rounded at the base by a row of large pores between which costal ridges 

 radiate toward the top, which bears a low, pointed umbo. 



Canu and Bassler (1928:108) described Hippomenella rubra 

 doubtfully on the basis of avicularia, which were not noted by Smitt 

 in his jnucronata, but there is the same variation among colonies from 

 the Eastern Pacific. Brown (1949:513-520) has recently studied the 

 type material of Hippomenella {Lepralia mucronelliformis Waters, 

 1899), has discovered the ovicell and has rejected mucronata (rubra) 

 as a member of that genus. I am placing the species in the genus 

 Hippopleurifera, with which most of its characters agree, though the 

 operculum is more complete proximally and the cardelles are sometimes 

 moderately large. 



