COELOCENTRUM. 45 



whorls, the tube being smooth, with some opaque whitish 

 streaks. Guatemala. 



Well distinguished by the narrowly coiled and very convex 

 whorls, which are much less numerous than in any of the 

 forms referred to C. arctispira. The sculpture, moreover, is 

 far finer than described for that species, being slightly finer 

 than in tomacdla. C. fistulare, which agrees in size with C. 

 tli*l>ar, is described as with slightly convex whorls, while in 

 di*l>ar the convexity is very conspicuous. The individual 

 whorls are shorter or lower than in fistulare, and the free por- 

 tion of the last whorl does not descend. Possibly Pfeiffer's 

 figures of fistulare pertain to C. dispar. Fig. 17 represents 

 the sculpture of the front of the penultimate whorl. 



C. ASTROPHOREA Dall. 



Shell .pale yellow-brown, decollate, with 15 remaining 

 whorls, the first six of which taper, while the rest are sub- 

 equal; suture distinct, minutely channelled, or with a sharp 

 edged thread on each side of it, surface polished with con- 

 cavely flexuous small ribs with wider interspaces, on which is 

 visible obscure spiral striation; last whorl keeled below, pro- 

 jecting, aperture rounded-triangular, slightly reflected, sim- 

 ple ; axis large, pervious except at the base ; within the whorl 

 with a medial keel on each side of which it is excavated and 

 vertically ribbed, while from the junction of keel and ribs 

 small spines like the rays of a star project into the lumen of 

 the whorl. Alt. 30, max. diam. 7, aperture 4.7 mm. (Dall). 

 Encarnadon, State of Hidalgo, Mexico (E. W. Nelson). 



C. astrophorea DALL, Nautilus xi, p. 62 (October, 1897). 

 "C. acantliopliorca Dall," v. MARTENS, Biologia Centrali 

 Americana, Moll., p. 634 (Feb., 1901). 



Though the spines [upon the internal pillar] are obviously 

 merely an evolution from the usual nodes, they are remark- 

 able, and hitherto unrecorded in any species. (Dall). 



C. LUDERSI (Pfeiffer). 



Shell perforate, oblong-cylindrical, widely truncate, rather 

 solid, finely and subarcuately striate, fleshy-whitish, whorls 

 remaining 8, flat, joined by a linear suture, the last provided 

 with a strongly projecting keel. Aperture slightly oblique, 



