46 BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 



appears to be the equatorial equivalent. AmpJiiUestrum Jlemingi is a species from 

 the cold and temperate regions; it occurs from the polar circle to the forty-fourth 

 parallel in depths where the temperature is from 3.1° to 6.7° C. Our American 

 species represent, therefore, the simplification which the warmth of the waters 

 may provoke in a species. 



Occurrence. — ^Miocene (Choctawhatchee marl): Jackson Bluff, Ocklocknee 

 River, 25 miles southwest of Tallahassee, Florida (rare). 



Holotype.— Cat. No. 68460, U.S.N.M. 



Genus RAMPHONOTUS Norman, 1894. 



(For description, see Bulletin 106, U. S. National Museum, p. 163.) 



RAMPHONOTUS ASPERUS. new species. 



Plate 13, figs. 11-13. 



Description. — The zoarium incrusts shells and masses of Stylopoma sjwngites. 

 The zooecia are elongated, distinct, oval, much enlarged at the base; the mural 

 rim is thin, much enlarged in the lower part of the cryptocyst, and bears two large 

 areal spines and generally four smaller ones; the opesium is anterior, oval, trifo- 

 liated, narrowed laterally by two little salient condyles on which articulates prob- 

 ably the opercular valve. The ovicell is hyperstomial, salient, globular, orna- 

 mented by a small transverse area. The avicularium is large, salient, transverse, 

 triangular, with beak pointed and tliin and placed regularly below each opesium. 

 Elongate zooecia: 



,, , ^ • (/to = 0.24 mm. „ • fis = 0.50 mm. 



Measurements. — Opesia , ^ „^ Zooecia , _ . _ 



^ I (0 = 0.20 mm. I (2 = 0.40 mm. 



Transverse (short) zooecia: 



„ . 1^0 = 0.18-0.20 mm. „ . (Ls=--0.44 mm. 



Opesia, -, „„ Zooecia , ... 



^ [to = 0.20 mm. I (.3 ==0.40 mm. 



Variations.— The zooecia are often short and wide. The number of spines is 

 variable and may be eight, but there are always two large hollow spines on the 

 ovicelled zooecia. The calcified and perforated zooecia and regenerated zooecia 

 are not rare. All of the avicularia are not large and transverse; they are some- 

 times much reduced and orbicular, especially in the vicinity of the ancestrula. 

 The walls are fragile and fossilization gives the species quite variable and curious 

 aspects (fig. 12). The dietellae are arranged as in Callopora (fig. 13). 



The presence of species of this genus seems to indicate that in the localities 

 where 'they lived the waters were calm and little rich in diatoms. 



Affinities. — This species differs from Ramphonotus agellus Ulrich and Bassler, 

 1904, in its triangular avicularium placed transversely. It differs from Rampho- 

 notus rhyncTiota Busk in its very different dimensions and in the presence of more 

 than two spines. 



Occurrence. — Miocene (Yorktown formation) : 3 miles southwest of Peters- 

 burg, Yorktown, Beulahland, King and Queen County, 1 mile northeast of Suffolk, 

 and other locahties in Virginia (rare) . 



Cotypes.—CsLt. No. 68461, U.S.N.M. 



