it curled up from the upper jaw for defensive or offensive purposes. This was justified by comparison to the upper tooth blades of Edestus, which by 1899 had been re-evaluated as structures belonging to the jaw. Debates over the identity of Helicoprion's tooth whorl were abundant in the years following Karpinsky's monograph. In 1900, the publication was reviewed by Charles Eastman, who appreciated the paper as a whole but derided the sketch of the supposed life position of the whorl. Though Eastman admitted that the teeth of the whorl were very similar to those of other chondrichthyans, he still supported the idea that the whorl may have been a defensive structure embedded into the body of the animal, rather than the mouth. Shortly after his original monograph, Karpinsky published the argument that the whorl represented a curled, scute-covered tail akin to that of Hippocampus (seahorses). This proposal was immediately criticized by various researchers. E. Van den Broeck noted the fragility of the structure and argued that it was most well-protected as a paired feeding apparatus in the cheek of the animal. A.S. Woodward (unrelated to Henry Woodward) followed this suggestion with the hypothesis that each whorl represented a tooth battery from a gigantic shark. G. Simoens illustrated Karpinsky's various proposals and used histological data to adamantly argue that the whorls were toothed structures placed within the mouth. In 1911, Karpinsky illustrated the whorls as components of the dorsal fins. Reconstructions similar to those of Karpinsky (1899) were common in Russian publications as late as 2001. Later reconstructions By the mid-20th century, the tooth whorl was generally accepted as positioned in the lower jaw of the animal. Though this general position was suspected almost immediately in the aftermath of Karpinsky's monograph, it was not illustrated as such until the mid-1900s. Around that time, an artist known only as "F. John" depicted Helicoprion within a set of "Tiere der Urwelt" trading cards. Their reconstruction presented the tooth whorl as an external structure curling down from the lower jaw of the animal. Similar downward-curling reconstructions have also been created by modern paleontologists and artists such as John A. Long, Todd Marshall and Karen Carr. The utility of the tooth whorl in this type of reconstruction was inferred based on sawfish, which incapacitate prey via lateral blows of their denticle-covered snouts. Information on the position of eugeneodont tooth whorls was bolstered by two major