42 COELOCENTRUM. 



knot-like. Crosse & Fischer's figures of the type are copied 

 on nry plate 9, figs. 17, 18. Pfeiffer 's figures of a form pos- 

 sibly referable to the next species are also given, figs. 19, 20. 

 C. ARCTISPIRA (Pfeiffer). PI. 14, figs. 33-36. 



Shell rimate, cylindric-turreted, broadly truncate, rather 

 solid, closely subarcuate- ribbed, somewhat opaque, whitish; 

 suture deep, subnodulose, whorls remaining 18, narrowly 

 coiled, convex, the last narrower, thread-carinate, shortly pro- 

 tracted forward. Aperture small, oblique, obliquely oval: 

 peristome continuous, glossy, narrowly reflexed throughout, 

 the left margin laterally produced. Length 38, diam. 10 mm. ; 

 oblique length of aperture 6%, width 6 mm. (Pfr.). 



Juquila, State of Oaxaca (Boucard, type locality) ; Istapa, 

 State of Tabasco (Salle). Var. estefania: at Quilate, Agua 

 Caliente, and Arroyo del Banco, all in the environs of Misantla, 

 V. C. (Dona Estefania Salas). 



Cylindrella arctospira PFR., P. Z. S. 1860, p. 139, pi. 50, f. 2 

 (see below under C. aristispica) . Cylindrella arctispira PFR., 

 Malak. Blatter viii, p. 81 ; Monogr. Hel. Viv. vi, p. 377 ; vii, p. 

 438. SOWERBY, Conch. Icon, xx, pi. 14, f. 123. Ccclocentrum 

 <ir<-{ ispinnn'C. & F., Moll. Mex. i, p. 348, pi. 15, f. 15. Mar- 

 tens, Biol. Centr. Amer., Moll., p. 271. ?STREBEL, Beitrag iv, 

 p. 58, pi. 6, f. 4 (shell) ; pi. 14, f. 3 (internal axis) ; pi. 11, f. 

 9, 15'; pi. 13, f. 10 (anatomy). 



The original description is given above, and the original fig- 

 ure is copied in my fig. 33 of pi. 14. This figure corresponds 

 with the original description neither in size nor the number of 

 \\ -hurls tnven by Pfeiffer, and therefore does not represent the 

 type specimen. In size, the figure given by Sowerby (pi. 14, 

 fig. 34) comes near Pfeiffer's measurements, though a little 

 larger, and it has the same number of whorls. Probably it is 

 Ihe type. This figure, however, shows a strongly ribbed shell 

 unlike the forms figured by Crosse & Fischer and by Strebel. 



C. arctispira as identified by Fischer and Crosse, from spec- 

 imens eulleeled by Salle at Istapa, State of Tabasco (pi. 14, 

 ligs. 35, 36), measures, length 36, diam. 10 mm., apert. with 

 pi-rist. (i mm. lung, 5 wide; whorls 17. It is quite solid but 

 sufficiently translucent to show the internal column indis- 



