434 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



COSTAZIA ACULEATA, new species 



Plate 63, fig. 4 



Description. — The zoarium is free, cylindrical, bifurcated. The 

 zooecia are distinct, separated by a furrow or by interzooecial avicu- 

 laria; the frontal is little convex, smooth, ornamented by rare areolar 

 pores. The apertura is orbicular with a small linear proximal rimule 

 cut in a special lamella; the peristomie is deep; the peristome is thin, 

 salient, ornamented by a small proximal avicularium, generally some- 

 what elongated and elliptical. The ovicell is convex, embedded in 

 the distal zooecium, adorned with a very fragile cribriform area. 

 The interzooecial avicularia are numerous, thin, narrowed in the mid- 

 dle. The beak is rounded and oriented as the zooecium more often 

 toward the base of the colony. 



Measure merits . — 



-n -x fft» = 0.14 mm. r , . \Lz = 0.50-0.56 mm. 



Peristome 7 _ ,_ Zooecia 7 nnA 



[Ip = 0.10 mm. 1/2 = 0.34 mm. 



Variations. — This is a species absolutely disconcerting in its unex- 

 pected aspects and its variable micrometrie measurements. All the 

 specimens are dissimilar, no one resembling another. There are never- 

 theless some common characters; deep aperture, small proximal 

 avicularium on the peristome, large interzooecial avicularia long and 

 thin, and cribriform ovicell. The measurements of the real aperture 

 are rather constant in spite of the variations of the peristome. 



The small lamella in which the rimule of the aperture is cut is 

 rarely visible, either that it is too deep, or that it is hidden by the 

 small peristomial avicularium. All the zooecia of the same branch do 

 not have the same orientation. 



Affinities. — Costazia aculeata belongs to a special group which we 

 refer provisionally to Costazia because of the presence of a cribriform 

 area on the ovicell. The chitinous appendages not being known, the 

 creation of a new genus is not desirable. The known species of this 

 group are Costazia aculeata, new species, Recent; C. (Cellepora) 

 yarraensis Waters 1881, Tertiary of Australia; C. (Haswellia) prod>/et<i 

 MacGillivray 1895, Tertiary of Australia; Costazia convexa, new name, 

 Tertiary of Australia; C. (Haswellia) longirostrls MacGillivray, 1S84. 



This species differs from Cellepora yarraensis Waters, 1881, in its 

 very little convex, cellular frontal, in the absence of a straight border 

 to the peristome and in its avicularia oriented toward the top of 

 the colony. 



Biology. — The geographic distribution of this species is rather great. 

 We have found it in fact from the Island of Shado in Japan, as far as 

 Borneo in the China Sea. It does not penetrate into the Archipelago 

 of the Philippines for we have found only a single specimen at Rom- 

 blon. Contrary to the other species of Costazia it descends to great 



