132 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



In this species the small avicularium is interzooecial and placed at 

 the base of each zooecium; it is oval or triangular and its beak is 

 very salient. The distal border of the mural rim bears sometimes 

 two avicularia placed almost symmetrically. This double arrange- 

 ment exists also in the species from the Jacksonian. 



The opesiular indentations are very shallow and very often they 

 even do not exist. The ectocyst is quite transparent and the oper- 

 cular valve is borne upon the distal border of the mural rim. The 

 ovicell is very small and endozooecial. 



According to Waters, 1898, the species from Bahia (1881) can not 

 be that from Tahiti (1885). As he has examined the types, we accept 

 his determination. Our specimens appear to be related to the species 

 from Tahiti figured by Hincks, 1885. We are not certain of our 

 determination, as Hincks did not give the micrometric measurements. 

 Biology. — Our specimens encrust shells and spines of echinoids. 

 They were dead except those from locality D. 5147. The species was 

 in reproduction, February 16, 1908. 

 Occurrence. — 



D. 5145. Jolo Light, Jolo; 6° 04' 30" N.; 120° 59' 30" E.; 23 



fathoms; co. S., Sh. 

 D. 5147. Salade Islands, Sulu Archipelago; 5° 41' 40" E.; 120° 



47' 10" E.; 21 fathoms; co. S. Sh. 

 D. 5151. Sirun Island, Sulu Archipelago, Tawi Tawi Group; 

 5° 24' 40" N.; 120° 27' 15" E.; 24 fathoms; co. 

 S., Sh. 

 D. 5235. Nagubat Island, east coast of Mindanao; 9° 43' N.; 



125° 48' 15" E.; 44 fathoms; sft. M. 

 Chatham Island (Waters); Red Sea (Waters). 

 Pacific: Tahiti (Hincks, 1885). 

 Plesiotypes. —Cat. Nos. 7933, 7934, U.S.N.M. 



DACRYONELLA OGIVALINA, new species 



Plate 13, fig. 8 



Description. — The zoarium encrusts pebbles and shells. The 

 zooecia are distinct, separated by a shallow furrow, little elongated, 

 broad, generally ogival; the mural rim is small, round, little salient; 

 the cryptocyst is smaller than the opesium, little deep, smooth. 

 The opesium is large, ogival, little elongated, somewhat convex 

 at the distal border. The small avicularia are interzooecial and 

 placed at the base of each zooecium; they are triangular, with slender 

 beak. 



Measurements. — 



\ho = 0.20-0.22 mm. n (£2 = 0.48-0.50 mm. 



Opesium 7 nio non Zooecium , 



v \lo = 0.18-0.20 mm. Us = 0.30 mm. 



