Plate 2. 



Page. 



Fig. 1. Dentalium texasianum cestum, new subspecies, 24 mm 29 



2. Dentalium texasianum rioense, median section 29 



3. Dentalium texasianum rioense, new subspecies. Type, 17.5 mm 29 



4. Dentalium texasianum cestum, posterior section 29 



5. Dentalium gouldii portoricense, new subspecies. Type, 42 mm 30 



6. Dentalium gouldii Dall. Type, 29 mm 30 



7. Dentalium gouldii Dall. Magnified sculptural detail 29 



8. Dentalium texasianum cestum, anterior section 29 



153 



