内毛目：动基片纲(Kinetofragminophorea)前庭亚纲(Vestibuliferia)中的一目，为包括类人猿在内的哺乳类草食动物的共生物，体纤毛已减为颇具特色的毛束或带，口纤毛明显，近口带由向胞口盘旋的微膜构成，口区有时可以回缩，表膜一般坚实并可伸展为突起，很多都具骨板- urethane
- urethra
- urethral
- urethralgia
- urethrascope
- urethratresia
- urethrectomy
- urethremphraxis
- urethreurynter
- urethrism
- urethritis
- urethro-
- urethroblennorrhea
- urethrobulbar
- urethrocele
- urethrocystitis
- urethrocystogram
- urethrocystography
- urethrocystopexy
- urethrodynia
- urethrograph
- urethrography
- urethrometer
- urethrometry
- urethropenile