386 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Microporella gibbosula Canu and Bassler, 1930 

 Plate 44, fig. 9 



Microporella gibbosula Canu and Bassler, 1930 :20. 



Zoarium encrusting shells, worm tubes, etc. The zooecia are moderate 

 in size, 0.50 to 0.55 mm long by about 0.45 mm wide, the front swollen 

 and smooth or with fine granules. The aperture is nearly as long as broad, 

 0.08 mm by 0.09 with the proximal border straight ; the peristome low 

 and smooth with 5 small oral spines. The ascopore is round and unusually 

 small, often with a small raised collar. There is one small avicularium 

 (rarely 2) situated usually in the lateral zooecial angle close to the 

 margin, oriented laterally, or slightly oblique, the mandible setiform or 

 somewhat lanceolate. 



The ovicell is globular, conspicuous, smooth and perforated and only 

 slightly ribbed about the base, width about 0.26 mm. The form of the 

 aperture, the small rounded ascopore and the position of the small avicu- 

 larium appear to be constant and are the most diagnostic characters. 



Described from the Galapagos Islands, Albatross Sta. D.2813. 



Hancock Stations: 8 stations among the Galapagos Islands; 431-35, 

 Octavia Bay, Colombia; 114-33, Bahia Honda, and 437-35, Secas Islands, 

 Panama; 309, Port Culebra, Costa Rica; and 298, Agua Verde Bay, 

 Lower California. 5 to 80 fms. 



Microporella coronata (Audouin), 1826 

 Plate 45, fig. 1 



Flustra coronata Audouin, 1826:239. 

 Microporella coronata. Waters, 1909:42. 

 Microporella coronata, Canu and Bassler, 1925:37. 

 Microporella ciliata var. coronata, Hastings, 1927:340; 1930:727. 



Encrusting on shells, etc. Zooecia of moderate size, usually between 

 0.45 and 0.55 mm long by 0.40 to 0.50 mm wide, but varying greatly; 

 distinct, the frontal somewhat ventricose with numerous small pores. 

 The aperture is semicircular, a little narrowed proximally, the proximal 

 border straight, width 0.13 mm, length 0.10 mm; peristome low and 

 thin, with about 6 oral spines the basal joints of which are dark. The 

 avicularia are paired, about opposite the asocopore and directed forward 

 and slightly outward ; the mandible has a hastate shape, the small lateral 

 projections usually bent downward like hooks and inconspicuous, the 

 distal portion slender with a setose point and a curved tip ; the rostrum 

 is short, grooved and truncate at the tip, extending only to the lateral 

 projections of the mandible. The ascopore is lunate in form. 



