FIGURE 19 in Illustrated Key to the Snakes of the Philippines

FIGURE 19. Ventral view of head of (A) Hologerrhum philippinum (KU 330065): five infralabial scales in contact with chin shields; anterior chin shields broadly contact infralabial scales 1–4; posterior chin shields broadly in contact with fourth and fifth infralabial scales; (B) Cyclocorus lineatus lineatus (KU 346571): five infralabial scales in contact with chin shields; anterior chin shields broadly in contact with infralabial scales 1–4; posterior chin shields broadly in contact with fifth infralabial scale; (C) Cyclocorus nuchalis nuchalis (KU 327765): four infralabial scales in contact with chin shields, anterior chin shields broadly in contact with infralabial scales 1–3; posterior chin shields broadly in contact with fourth infralabial scale.