382 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Genus ADEONELLOPSIS MacGHIivray, 1886 



ADEONELLOPSIS PENTAPORA, new species 



Plate 53, figs. 1-5 



Description. — The zoarium is free, bilamellar; the fronds are flat 

 or somewhat undulated, compressed, narrow, bifurated; the base is 

 very narrow. The zooecia are distinct, separated by a deep fur- 

 row, surrounded by a line of small parietal dietellae, elongated, 

 pyriform; the frontal is a large smooth pad surrounding a depression 

 in which are lodged the apertura, the avicularium and the cribriform 

 area. The apertura is little visible, embedded, semicircular, trans- 

 verse; the cribriform area is small and perforated by three stellate 

 pores. Between the apertura and the cribriform area there are two 

 small avicularia very little separated, sometimes adjacent and 

 symmetrically arranged. On the frontal, at the base of each zooecium 

 there is a salient, poriform avicularium. 



Measurements . — 



Apertura!^ -°- 04 mm ' Zooecia!^ -0.35-0.40 mm. 



(la =0.07 mm. \lz =0.30-0.35 mm. 



Affinities. — We have not found young branches and we are ignorant 

 of the aspect of the young zooecia but we know that in the genus 

 Adeonellopsis the zooecial variations on the same colony are very 

 large. The aperture, the two avicularia, the cribriform area and the 

 frontal avicularia form a group of 5 pores which occasions our speci- 

 fic name. The species differs from Adeonellopsis symmetrica Waters, 

 1881, in a much smaller cribriform area, in the presence of a frontal 

 avicularium and in its fronds three times as broad. It differs from 

 Adeonellopsis coscinophora Kirkpatrick, 1890 (not Reuss, 1847), in 

 its much smaller cribriform area provided with fewer pores and in 

 the little separation of the oral avicularia. When the variations of 

 the two species are better known it may be necessary to unite them. 

 It differs from Adeonellopsis tuberculata Busk, 1852, figured by 

 Ortmann, 1890, in the nearness of the avicularia, in a smaller area 

 and much smaller dimensions. 



The figures of Kirkpatrick, 1890, and Ortmann, 1890, represent the 

 young zooecia so that comparison with our specimens presents 

 necessarily uncertainties. 



Biology. — All our specimens were dead. The one from Mompog 

 is much worn and it can not be proved that it lived at the depth 

 considered. Everywhere this species is rare. 



The base that we figure is more narrow than a frond. Ortmann, 

 1890, has figured a specimen of the related species Adeonellopsis 

 tuberculata Busk, 1852, attached to a minute gastropod. All the 

 colonies of the various species of this genus assure their equilibrium 

 by themselves, magnificent example of vital unity. Each cell is an 



