346 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Hippoporina tuberculata new species 

 Plate 43, fig. 10 



Zoarium encrusting on a shell. Zooecia small, 0.40 to 0.45 mm long 

 by 0.25 to 0.35 mm wide, moderately distinct, ovate and arranged in 

 quincunx; the frontal is a granulated pleurocyst, little inflated, with a 

 few small inconspicuous areolar pores. The aperture is elongate, about 

 0.12 mm long by 0.09 mm wide, the anter somewhat pyriform, the 

 cardelles very strong, pointed and directed backward, the poster broadly 

 arcuate and varying in width; the operculum has the form of the aper- 

 ture, well chitinized with a narrow sclerite paralleling the border. The 

 peristome is low, thin, smooth, without spines and is not covered by the 

 surrounding frontal wall. Small frontal avicularia are rare. The most 

 unusual feature for this genus is the presence of low conical tubercles, 

 one of these usually occupies the position of a median suboral umbo, 

 one to three on each side of the aperture and one or more on the frontal. 

 Dietellae are present. 



Ovicells are wanting on our small specimen. 



It is similar in most respects to H. porcellana, but the measurements 

 are all smaller, the poster wider and shallower, and the conical tubercles 

 give the frontal a very different appearance. 



Type, AHF no. 68. 



Type locality, Hancock Station 438, Chatham Island, Galapagos, 

 0°46'10''S, 89°30'10"W, at 35 to 40 fms. One small colony. 



Hippoporina contracta (Waters), 1899 

 Plate 41, figs. 4-5 



Lepralia contracta Waters, 1899 :11. 



Lepralia serrata Oshurn, 1912:242. 



Lepralia contracta, Norman, 1909:306. 



Lepralia contracta serrata, Osburn, 1914:211. 



Perigastrella contracta, Canu and Bassler, 1920 :576 ; 1929 :403. 



Perigastrella contracta, Hastings, 1930:722. 



Perigastrella contracta, Marcus, 1937:98. 



Hippoporina contracta, Osburn, 1940 :428 ; 1947 :33. 



Zoarium encrusting, often multilamellate, sometimes rising into ridges 

 or frills. The zooecia are ovate or hexagonal, distinct when young but 

 later immersed in a common crust. The front is a granular olocyst 

 (? pleurocyst), thick, vitreous, with irregular tuberosities and marginal 

 areolae. The aperture is somewhat elongate, rounded distal to the strong 

 cardelles which are often more or less bifid; proximal to the cardelles 



