The original description of Caecum debile A. E. Verrill and Bush, 1900 is brief and scarcely distinguishes it from C. delicatulum and C. crispum, all three named from Bermuda in the same paper. None was said to have an apertural varix or constriction, and only the latter two were illustrated. Lightfoot (1992) took these three to be synonymous with C. heladum Olsson and Harbison, 1953, and Absalão and Gomes (1998)  put C. debile in the synonymy of C. multicostatum de Folin, 1867. Later Absalão and Gomes (2001), while omitting any mention of C. debile (??!!!), placed C. heladum in the synonymy of C. multicostatum de Folin, 1867. The above illustrated specimen differs from C. heladum, principally in the apertural sculpture, but somewhat resembles this character in the type figure of C. multicostatum.  See further discussion at A new perspective on Caecum breve and C. debile

    There is  little doubt that the species illustrated above, with its subtle varix and constriction at the aperture, and which I also have from Nevis, is the taxon De Jong and Coomans (1988) described and illustrated as C. debile A. E. Verrill and Bush, 1900,  and there is a good chance it is  in fact the Verrill and Bush taxon. See A new perspective on Caecum breve and C. debile for a further analysis of this historically misunderstood species and a novel synonymy.

Absalão, R. S. and R. S. Gomes, 1998. Caecum debile Verrill and Bush, 1900 as a synonym of C. multicostatum Folin, 1867 (Gastropoda: Caecidae). Abstracts of the World Congress of Malacology, Washington, DC 25-30 July 1998. Chicago, 1998. Not seen in its entirety.

Absalão, R. S. and R. S. Gomes, 2001.  The species usually reported in the subgenus Brochina (Caecum, Caecidae, Caenogastropoda) from Brazil and some relevant type specimen from the western Atlantic. Bolletino Malacologico 37(1-4): 9-22.

De Jong, K. M. and H. E. Coomans, 1988.  Marine gastropods from Curaçao, Aruba and  Bonaire. E. J. Brill, Leiden, v + pp 1-261 incl. 47 pls.

Folin, L. de, 1867. Chapitre VIII Rade de la Guayra. Les Fonds de la Mer 1: 30-33, pls. 3-4 Savy, Paris. <http://www.biodiversitylibrary.org/item/108784#page/42/mode/1up>

Lightfoot, Joanne, 1992b.  Caecidae of the western Atlantic Part 2. Of Sea and Shore 15(1): 23-32.

Olsson, A. A. and A. Harbison. 1953. Pliocene Mollusca of Southern Florida, with special reference to those from North Saint Petersburg. Monographs of the Academy of Natural Sciences of Philadelphia 8: vii + 459, 65 pls. 6 Nov.

Verrill, A. E. and K. J. Bush, 1900. Additions to the marine Mollusca of the Bermudas. Transactions of the Connecticut Academy of Arts and Sciences 10: 513-544, pls. 63-66. Sept. <http://www.biodiversitylibrary.org/item/48107#page/543/mode/1up>