The ridge that extends horizontally between the buccal and lingual cusps on premolars is called the transverse ridge. This anatomical feature is significant in the morphology of premolars and molars, serving as a prominent elevation on the occlusal surface.

- The transverse ridge is formed by the union of the buccal triangular ridge and the lingual triangular ridge of a cusp.
- It runs across the occlusal surface connecting the buccal and lingual cusps, which help in the grinding function of the tooth.
- It is distinct from the oblique ridge, which is found mainly on maxillary molars and runs obliquely across the occlusal surface.
- The marginal ridges are the raised borders found on the mesial and distal edges of the occlusal surfaces, not horizontally connecting cusps.
- The cingulum is a convex area on the cervical third of the lingual surface of anterior teeth, unrelated to cusp ridges.

Therefore, the correct answer is Transverse ridge.

Reference: Wheeler's Dental Anatomy, Physiology and Occlusion, Volume 1, Chapter on Tooth Morphology, Page 150