NO. 1111. 



PROCEEDINGS OF THE NATIONAL MUSEUM. 347 



Subgenus METASTOMA, Strebel and Pfeffer. 



Axis smooth, without plaits or siuiiosity; peuultimate whorl without 

 iuternal larain*. 



Ty^ye. — II. roenieri, Pfeiffer. 



This comprises most of the species included hitherto under the uame 

 of Rolosinra. 



Subgenus COELOSTEMMA, Ball. 

 Coelosiemma, Daix, N.iiitilus, IX, p. 50; Proc. U. S. Nut. Mas., XVIII, p. 3, 1895. 



Axis vertically ribbed as iu Goelocentrum, capacious, shell otherwise 

 as in Metastoma. 



Type.—E. elisabetha', Tilsbry. 



The Holospiras are included iu a subfamily Eucalodiinaj of the 

 Pupid*, by Crosse and Fischer, though formerly referred to the Cyliu- 

 drellida\ It might, perlmps, be premature to attempt to separate this 

 group as a family from the Pupida-. There are, however, some inter- 

 esting parallels in the groups included under the names of Cerlon, 

 Holospira, Coelocenfrum, and Encalodmm. These groups seem to vary 

 in somewhat similar directions as regards internal characters. Thus 

 Goelocentrum is characterized by curious vertical ribs on the axial wall, 

 such as exist in Holospira {CocJostemrna) c4izahethw, Vilshry-, the shell 

 is habitually decollate, with a pervious axis, and externally flexuously 

 ribbed with transverse riblets. A few species have also spiral stria- 

 tiou. To this group Crosse and Fischer re ferred the CylindreUa irreg- 

 ularis of Gabb from Lower California, which by its general character 

 is doubtless most nearly related to Coelocentrum, but differs by want- 

 ing the most remarkable of the generic characters assigned to that 

 genus. Instead of having the axial wall vertically ribbed as in Coelo- 

 ttemma, it has a revolving inflation extending the whole length of the 

 axis as in Bostrichocentrum, and should therefore be separated as a sub- 

 genus for which I have proposed the name Spartocentrum .^ In this 

 conclusion Mr. Pilsbry agrees, and I take tliis opportunity of express- 

 ing my serious obligations to that gentleman for valuable advice and 

 suggestions afforded during the course of a free correspondence relat- 

 ing to the subject matter of the present report. 



In the genus Euealodium, Crosse and Fischer, we have an allied 

 group habitually decollate like Coelocentrum, but having a solid axis. 

 They are large shells living on the surface of the ground in moist places, 

 under dead leaves and similar accumulations. Ilere also we find two 

 groups indicated by the internal characters of the axis. The typical 

 species, E. (jieshrechtii, Pfeiffer, has the axis sinuous and provided with a 

 plait extending its whole length, except in the immediate vicinity of the 

 aperture. The radula is wide with a fornuila of 05 : 1 :(35 for the trans- 

 verse row. The other group has a straight, smooth axis and a narrow 



' ' Nautilus, IX, p. 51, Sep^, 1895 ; Proc. U. S. Nat. Mus., XVIII, p. 3, 1895. 



