424 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



like the ordinary Ammodiscus^ but the color is a peculiar, dark red- 

 dish brown. A description of the genus and species follows : 



Genus AMMODISCOIDES, new. 



Test free, spiral, consisting of an initial chamber followed by a 

 nonseptate tube, the early portion forming a holloAv cone; later por- 

 tions becoming usually conical in the opposite direction from that of 

 the younger portion, wall finely arenaceous, smooth. 



This genus is split off from Ammodiscms which is planospiral both 

 in the young and later development, while the genus Aminod i<^eoides 

 has a definite conical young and broadly flaring later development. 



Tyjye of the genus. — Ammodiscoides turhinatus. 



AMMODISCOIDES TURBINATUS, new. 



Test of fine sand grains with a chitinous cement, surface smooth, 

 of a dark reddish brown color, revolving edge flattened, making the 

 aperture low ancL broad, quadrangular, entire test consisting of as 

 many as thirty coils, those of the early conical portion of nearly uni- 

 form diameter, the later ones gradually increasing in height and 

 width. 



Maximum diameter of fully developed specimens, 3 mm. 



Ti/pe.— Cut. No. 7717, r.S.N.M., from AJbatros^ station 2383, 1,181 

 fathoms, in the Gulf of Mexico. 



EXPLANATION OF PLATE .33. 



Fig. 1. Complete specimen X 20. 



2. Younger specimen X 45. 



3. Apertural view of a still younger specimen showing the conical young 



X GO. 



4. The young portion of the test without the Inler coils X Tf). 



5. G. Diagranunatic sections showing the reversing of the conical form in 



the later coils X 45 X GO. 



