92 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



The zooecia are very fragile; when they have disappeared, an elliptical cavity 

 is left on the substratum, as if the latter had been eroded. Conopcum r-onracum 

 also possesses this peculiarity; but even when occurring- together on the same shell. 

 the two species can not be confounded, since the latter is provided with a concave 

 rryptocyst and has no elevated gymnocyst. 



Again, this species differs from Conoj>< nm wilcoxianicunt in the thinness of its 

 mural rim, and from ('. lin-i-oi.i-ii in the rare occurrence of its interopesia] cavities. 



Occurrence. Lower Jacksonian (Moodys marl): Jackson. Mississippi (rare-). 



Geological distribution. Xummulitic limestone of India (Haime) ; Priabonian 

 of Vicentin (Reuss, Waters). 



/Vr.wW///*, . Cat. Xo. 63869, IT. S. X. M. 



CONOPEUM CONCAVUM. new species. 



Plate 10. tigs. 11-13. 



l>, K< -i i/it/nii. The zoarium consists of large colonies incrusting shells. The 

 zooecia are distinct, elongated, elliptical: the mural rim is very thin, but it is much 

 enlarged proximally, forming a true cryptocyst, always i-aiK-tirc. The opesium is 

 regular and elliptical. The interoposial cavities are large, triangular; they often 

 join each other and become confluent. The dorsal which excavates in the sub- 

 stratum. bear- I wo impressions and two distal septulae. 



(Afl = 0.28-0.32 mm. . /.z=0.36-0.40 mm 



Measurem <nfs.< )pesia 7 Zooecia , 



[lo O.ls-U.20 mm. Us=0.24 mm. 



A-ftiiiit'x-s. Like Conopeum hooil'i'-i this species appears to excavate a place 

 for itself in the substratum, but it presents furthermore some remarkable peculi- 

 arities. The opesium of certain zooecia is do-ed by a perforated lamina. In the 

 articulated species, such zooecia correspond to the radicular pores, but here we are 

 totally ignorant of their function. On other zooecia there is a genuine cryptocyst 

 and an aperture closed by a calcified opercuhun. Finally, total regeneration mani- 

 fests it-elf by a secondary mural rim within the opesium. 



This species differs from fniin/n-mi/ irilcoxianiciim in its thin mural rim. 

 from (''. hoockeri. in its concave cryptocxst and its intempesial cavities, and from 

 ('. /i/i fi/'.ii in its concave cryptocyst. 



Occurrence. Lower Jacksonian (Moodys marl): Jackson, Mississippi (rare). 



Yickshurgiaii (Byram marl) : Yicksburg, Mississippi (rare 1 ). 



C'otypes.C&t. Xo. (i38Tu. I'.S.N.M. 



CONOPEUM LAMELLOSUM. new species. 



Plato -i'. i\i:s. l-',i. 



]>< ,M rijit'ion. The zoaria are large undulating fronds formed of multiple 

 lamellae growing back to back. The zooecia are distinct, somewhat, elongate, 

 elliptical; the mural rim is flat, finely punctate, projecting distally. and enlarged at 

 the base into a small cryptocyst. The opesium is regular, elliptical, entire or very 



