A thorny tree, sometimes exceeding 6.5 meters in height; spines medium large and sharp; leaves 13.5 to 18 centimeters long, 4 to 6 centimeters broad, ovate to oblong ovate, coriaceous, dark green and shining above, crenate; base rounded to broadly acute; apex acute, sometimes emarginate; petiole 5.5 to 8 centimeters long, broadly margined, sometimes 4.5 centimeters wide, wing area inferior or equal to sometimes exceeding leaf area; flowers 4 to 7, in axillary or terminal, compact cymes, 17 to 28 millimeters in diameter; calyx small, not cupped; petals 4 to 5, oblong ovate, white, with trace of purple on the outside; stamens 30 to 36, equal, free, with abundant pollen; ovary rather large, globose, 13 to 18 loculed; style short and stout; stigma knob like; fruit subglobose to short pyriform or turbinate, attaining a length of 9 centimeters and a diameter of 7 centimeters; surface smooth; color greenish yellow to lemon yellow; rind medium thick; pulp greenish, juicy, sharply acid, aromatic; juice sacs rather short and blunt, usually containing a more or less distinct nucleus; seeds usually many, flat, reticulate. This fruit, commonly called cabuyao by the Tagalogs in central Luzon, is without question the "copahan" of Bohol. Near Manila the tree has been found in flower in September, while in Bohol flowers were collected in May. The fruit may be used in making ade, but is inferior to the lemon or lime. The native inhabitants eat it together with fish, and also use the fruit in washing. It is of practically no importance. The "amongpong," found in Bohol, and considered a distinct fruit from the copahan by the native inhabitants, differs chiefly in having only 26 to 30 stamens, and a large oblate ovary with a short and slender style. The first has not been examined by the writer and is said to be smooth and short, pyriform, 10 centimeters in diameter. Flowers examined in May. "Calo-oy" is another fruit also found in Bohol considered by the inhabitants as distinct from the "copahan" and "amongpong." The leaf characters in the calo-oy scarcely differ sufficiently to entitle it to rank even as a subspecies; the flowers were just gone when the visit was made to Bohol. The fruit is said to be globose, smooth and about 8 centimeters in diameter. "Amontay" (Pl. IVb) is still another form of C. histrix found in Bohol. This plant was also out of its flowering stage at the time of the visit. The fruit, forwarded to the writer in February by Mr. Southwick, is about 88 millimeters in diameter, irregularly globose, with flattened or depressed base, and rounded apex, smooth, lemon yellow; oil cells mostly raised; skin thick; the pulp, contained in 10 to 12 locules, juicy, and rather pleasantly aromatic; juice cells medium large, short and plump, containing a minute, greenish nucleus; cotyledons supraterraneous, distinct.