Asymmetrical biraphid diatoms have a raphe system on both valve faces but are asymmetrical over either the apical or transapical axis.  To indicate locations and positions of features on the diatoms, there is some terminology specific to asymmetrical biraphids.  If the diatom is asymmetrical across the apical axis, the larger+more arched side is the "dorsal" side, and the thinner+flatter side is the "ventral" side.  If the diatom is asymmetrical across the transapical axis, the wider end is called the "headpole" and the skinnier end is called the "footpole."