DR. ERNST'S abnormal fruit of Opuntia, as figured at p. 77, appears to be similar to one described and illustrated by Zuccarini (Abhandl. d. math. phys. Class., B. iv., Abth. I., tab. ii.) in the case of Cereus serpentinus, but as Dr. Ernst gives no details as to the arrangement of the vascular bundles, it is impossible to say that the two cases are exactly parallel. The resemblance to certain gourds (Cucurbits), wherein the upper part of the fruit protrudes beyond the dilated end of the flower-stalk, may also be pointed out.