Distal raphe
The portion of the raphe system that is near the valve end, or valve apices.
Citations
Barber, H.G. and Hayworth, E.Y. (1981). Guide to the Morphology of the Diatom Frustule. Freshwater Biological Association, 112 pp.
Image Credit: Sarah Spaulding
Light micrograph of the end of a species in the genus Encyonema. The arrow indicates the distal raphe, which is ventrally deflected.
Image Credit: Ditmar Metzeltin
Scanning electron micrograph of a member of Diploneis. The two arrows show the distal raphe ends, which are unilaterally (to the same side) deflected.