COELOCENTRUM. 43 



tinetly through the shell ; sculptured with close and distinctly 

 arcuate riblets ; light fawn-colored. The internal structure is 

 unknown, and the identity of the form with Pfeiffer's type is 

 not unquestionable. 



Cylindrella aristispica "Pfr. MS." of Sowerby, 1875, was 

 based upon tiic specimen figured as arctispira in the Proc. 

 Zool. Soc. 1860, pi. 50, fig. 2 (my pi. 1-1, fig. 33), although this 

 identity was not recognized by Sowerby and has not hitherto 

 been announced. The status of C. arctispira being uncertain, 

 as explained above, that of Sowerby 's species (the name of 

 which is probably due to the misreading of a label) awaits 

 examination of the types. Sowerby 's description follows: 



"Shell solid, rather pyramidal, tumid below the middle, 

 olive-brown striped with reddish-brown, regularly striated, 

 contracted above, rather ventricose in the middle and below; 

 permanent whorls 16, depressed, last contracted, notched 

 [rimate] ; aperture roundish, margin thick, round, columella 

 slightly plaited. Habitat unknown." (Soivb.) 



"Cyl. aristispica Pfr. ?MS. Brit. Mus.," SOWERBY, Conch. 

 Icon, xx, pi. 1, f. 5 (1875) ; C. aritispica Pfr., SOWERBY, in in- 

 dex to Cylindrella. C. aristispira Sowerby, v. MARTENS, 

 Biologia, Moll., p. 272. 

 Var. ESTEFANIAE nov. PI. 14, figs. 28, 29, 30, 31, 32. 



The specimens from Quilate, Agua Caliente and Arroyo del 

 Banco, all near Misantla, reported by Strebel, have a feeble 

 satin sheen, are but little transparent, and dirty yellowish or 

 yellowish-brown in color, with sparse, narrow, somewhat 

 darker growth-streaks. The shell is more or less tapering- 

 above, and has 17 to 20 whorls remaining, which are moder- 

 ately convex and proportionately lower than in C. tomacella. 

 The last whorl shows the umbilical keel only slightly, but the 

 dorsal keel or cord is distinctly developed ; it runs free some- 

 what longer than in tomacella and fistularc, but does not de- 

 scend. The external sculpture consists of fine closely placed 

 scarcely arcuate ribs, of which there are about 200 on the 

 broadest (9 mm.) whorl. The axial tube is comparatively 

 broad, only moderately swollen Avithin each whorl. The 

 lamella? upon its outer surface are similar to those of C. toma- 



