90 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



case of doubt the conscientious naturalist should remain silent or should figure the 

 specimens. 



The lucid spots are rather irregular on the recent specimens. Canon Norman 

 was unable to see them, but Osburn has figured them. We have not observed them 

 in all cases. On the fossils the corresponding distal impressions are very incon- 

 stant. They are visible on certain specimens and have disappeared entirely on 

 others. The granulations of the mural rim are very inconstant, and we have 

 observed but a single case of total regeneration. 



This species differs from <'<moi>< nm wUcoxiamicum in the thinness of its mural 

 rim, from C. hoo<-/.'cri in the absence of the hump-like gymnocyst, and from C. ron- 

 cavum in the absence of the proximal concave cryptocyst. Its zooecia do not 

 excavate the host like the two latter forms. 



Occurn net . Claibornian (Lisbon formation) : Wautubbee Hills, 4 miles south 

 of Enterprise, Clarke County, Mississippi. 



Lower Jacksonian (Moodys marl) : Jackson, Mississippi. 



Middle Jacksonian: Eutaw Springs, South Carolina. 



Geological iJixtrilmfiini. Lutetian, Auversian, and Stampian of the environs of 

 Paris (Canu) : Miocene of Tunis (Canu) ; Burdigalian of Gard and of Herault in 

 France (Canu) : Helvetian of Italy (Michelin, Seguenza), of Gard, of Herault, and 

 of Touraine in France (Canu) ; Tortonian of Austria-Hungary (Reuss) ; Plaisan- 

 cian of England (Hineks); Quaternary of England (Bell) and of Argentina 

 (Canu). 



Hablh/f. The habitat of this species is still very obscure on account of the 

 difficulty of its determination. It certainly exists in the North Atlantic off the 

 coasts of France. England, Canada, and the United States and in the Pacific off 

 Alaska and California. It has not yet been observed with certainty in the Mediter- 

 ranean and in the tropical zone. Bifwtra lacroi.rii Smitt found off Florida appears 

 to be a different species, and Osburn. who has rediscovered Smitt's species, also 

 doubts its identity. 



Conopeum l<i<T<>i.i-i/ does not appear to inhabit the great depths, but it is 

 common near the shores. 



Plesiotyj>c.('i\t. No. G3s45, U.S.N.M. 



CONOPEUM TUBEROSUM, new species. 



Plate 19. figs. 6, 7. 



Description. The zoarium incru^ts oysters. The ancestrular zooecia are 

 isolated. The zooecia are elongated, distinct, elliptical, or pyriform; the gymnocvst 

 is inconstant, small, convex, bearing very often a small tuln rosity ; the mural rim 

 is wide, flat, finely striated, with an acute termen. a little enlarged at the base. The 

 opesium is large, elliptical, very finely crenulated. The interopesial cavities are 

 irregular, inconstant, triangular, or lozenge-shaped. 



i ho =0.22-0.26 mm. fZ2:=.0.40 mm 



Measurements. Onesnun /ooecmm- , 



'6 mm. \lz 0.28-0.30 nun. 



