48 COELOCENTRUM, SECT. LIOCENTRUM. 



rather widely spaced, narrow, arcuate riblets, about 2 in the 

 space of 1 mm. on the front of the penultimate whorl, becom- 

 ing irregular, crowded, or in part obsolete on the latter part 

 of the last whorl; the interstices finely wrinkled or striate 

 spirally. Whorls remaining 11%-12, convex, closely coiled, 

 the last produced forward, rounded beneath, the base defined 

 by a low cord or none. Aperture slightly oblique, irregularly 

 rounded, the peristome expanded and narrowly subreflexed 

 throughout. Internal axis smooth, polished, distinctly swol- 

 len within each whorl. Length 23.6, diam. 7.5 mm.; longest 

 axis of aperture 4.6, width 4.2 mm. 



State of Vera Cruz, E. Mexico: Cordova (Guillarmod and 

 Salle) ; Orizaba, about 500 ft. above the town (Heilprin 

 Exped.). 



Cylindrella filicosta SHUTTL., Diagn. neuer Moll., iii, p. 36, 

 in Mittheil. der Natur. Ges. in Bern, 1852, p. 296. PFR., 

 Monogr. iii, p. 573 ; Conchyl. Cab., p. 19, pi. 2, f . 30, and pi. 8, 

 f. 9, 10. SOWERBY, Conch. Icon, xx, pi. 12, f. 107. Ccelocen- 

 irum filicosta FISCHER & CROSSED Moll. Mex., i, p. 352, pi. 15, 

 f. 17, 17 a. STREBEL, Beitrag, iv, p. 61, pi. 5, f. 14. MAR- 

 TENS, Biologia, p. 272. 



A somewhat smaller species than C. crosseanum, with 

 slightly more spaced ribs, and the internal pillar is swollen 

 near the middle. It must be by a mistake that Fischer & 

 Crosse figure and describe the axis of filicosta as "rather dis- 

 tantly, somewhat obliquely and obsoletely ribbed;" for three 

 specimens I have opened, as well as those examined by Stre- 

 bel, present but a smooth pillar. 



A specimen from Orizaba (pi. 18, figs. 39, 40) measures, 

 length 25, diam. 7 mm., aperture 4 x 3.8 mm., and retains 14 

 whorls. It has the internal sculpture and the pillar of the 

 species, and cannot be referable to crosseanum. A very 

 young specimen (pi. 18, fig. 38) shows the dome-shaped first 

 whorl to be smooth. The next 5 whorls are equal in diameter, 

 weakly ribbed below the suture. The whorls then increase 

 rather rapidly in diameter,and the rib-sculpture of the adult 

 form begins on the ninth one. The detail figure of sculpture 

 (fig. 39) is from the front of the antepenult, whorl. 



