No. 2327. THE ANNULARIIDAE— HENDERSON AND BARTSCH. 75 



obsolete cords, the intersection of which with the axial ribs lorms 

 lubercles ranging in strength from minute to strong and hollow pro- 

 jections. Operculum with the calcified spiral lamella rising vertically 

 from the whorl. Dedicated to Dr. W. L. Abbott. 



Ty2)e of the genus. — ChoanoiJoma moreletiamim Crosse. 

 The follomng species are now referred to this genus: 



Cyclostoma tentorium Pfeiffer Haiti-Santo Domingo. 



Choanopoma solutum (Richard) Pfeiffer Santo Domingo. 



Choanopoma newcombi Crosse Santo Domingo. 



Choanopoma rosaliae Pfeiffer Santo Domingo. 



Cyclostoma (Choanopoma) adolfi Pfeiffer Santo Domingo. 



Choanopoma gabbi Crosse Santo Domingo. 



Choanopoma morletianum Crosse Santo Domingo. 



Choanopoma wilhelmi Pfeiffer Santo Domingo. 



Genus TUDORA Gray. 



1850. Tudora Gray, Brit. Mus. Cat. Cycloph., p. 48. 



Shell ranging from helicoid to elongate-conic in form, marked by 

 axial ribs only, or with axial ribs and spiral sculpture. The latter 

 may be confined to the umbilicus or may be present on spire and base. 

 The axial sculpture varies from strong to almost obsolete, or it may 

 consist of slender sublamellar riblets. The spiral sculpture is equally 

 variable as far as strength is concerned in the different species. 

 Breathing devices are not present in this genus. The operculum has 

 a basal chondroid plate composed of a number of whorls, the inner edge 

 of which develops a strong calcified lamella which is reflected out- 

 ward until it parallels the base. The lamellae are usually marked 

 by fine retractively slanting striations or riblets. 



Type of the genus. — Cyclostoma megacheilos Potiez and Michaud. 



TUIX)RELLATA, new subgenus. 



Shell helicoid. The axial sculpture ranges from regular simple 

 closely crowded ribs to distantly spaced ribs with finer threads be- 

 tween. The spiral sculpture is present in varying intensity in the 

 different species. The open umbilicus may or may not be bounded 

 by a spiral cord. Operculum typically Tudoroid. 



Type of the subgenus — Cistula intersiitialis (Gundlach) Pfeiffer. 

 The following species are now referred to this subgenus. They fall 

 into two groups as follows : 



The group of Tudorellata inter stitmlis: 



Cyclostoma roemeri Pfeiffer Eastern Cuba. 



Cistula mackinlayi (Gundlach) Pfeiffer Eastern Cuba. 



Choanopoma yateracense Pfeiffer Eastern Cuba. 



Annularia ramsdeni Pilsbry and Henderson Eastern Cuba. 



Cyclostoma hej/nemani Pfeiffer Eastern Cuba. 



Cistula intersiitialis (Gundlach) Pfeiffer Eastern Cuba. 



Annularia mayensis Torre and Ramsden Eastern Cuba. 



