AET. 14 i'OSSIL AFD EECEN"T BEYOZOA CANU AND BASSLER 105 



subject to the same phenomenon so that opercula of all the sizes can 

 be found. We have figured some of them. In comparing them 

 with those of Waters, 1899, it is easy to note that they have neither 

 the same proportions nor the same size and that they belong to a 

 perfectly distinct species. The zoarial avicularium is rather rare ; we 

 have, however, observed it twice on the ancestrula. The operculum 

 does not close the ovicell. 



Biology. — The colonies are rarely unilamellar and free; they gener- 

 ally encrust shells, Cellepores, corals, and hydroids; three specimens 

 were plurilamellar; but this celleporoid structure is very rare. "The 

 color of the colony is shining white, either pure or with a bluish tinge" 

 (Smitt). Our living specimens were in reproduction in May-April, 

 1885. This is one of the more common species of the Gulf of Mexico. 

 It will be easy to dredge hving specimens to study the larva, which 

 appears to us poorly classed in the Escharellidae and its great bathy- 

 metric range should correspond to a larger geologic distribution. 

 Kirkpatrick believed he had discovered it in China, but he did not 

 figure his specimens. The species discovered in Japan by Ortmann, 

 1890, and in Queen Charlotte Island by Hincks, 1884, appear to 

 approach more Hippoporina porcellana Busk, 1860. 



Occurrence. — Albatross Station D. 2167, oft' Habana, Cuba; 23° 10' 

 40'' N.; 82° 20' 30" W.; 201 fms.; coral. 

 Albatross Station D. 2365, east of Yucatan; 22° 18' 

 00" N.; 87° 04' 00" W.; 24 fms.; white rock coral. 

 Albatross Station D. 2405, Gulf of Mexico; 28° 45' 

 00" N.; 85° 02' 00" W.; 30 fms.; gray sand, broken 

 coral. 

 Albatross Station D. 2639, Straits of Flordia; 25° 04' 

 50" N.; 70° 53' 00" W.; 133 fms.; green sand. 

 Plesiotypes. —C&t. Nos. 7517, 7518, U.S.N.M. 



Fowey Light, 15 miles south of Miami, Fla.; 40 fms. 

 Florida, 48-194 meters (Smitt). 



Pliocene : Minnitimmi Creek, Bocas Island, Almirante 

 Bay, Panama. 



Genus HIPPADENELLA Canu and Bassler, 1917 



HIPPADENELLA FLORIDANA, new species 



Plate 9, Figure 8; text Figure 19o 



Description. — The zoarium creeps over chitinous sponges. The 

 zooecia are distinct, separated by a deep furrow, elongated, elHptical, 

 more or less broad; the frontal is very convex, bordered by areolar 

 pores, covered with a pleurocyst; the avicularian chamber is small, 

 convex, little salient, median. The aperture is suborbicular, two 

 short and broad cardelles separating a large anter from a small poster, 



