which survive, particularly in the form of wind chimes (tintinnabula). Some scholars have even interpreted the plan of the Forum Augustum as phallic, "with its two semi-circular galleries or exedrae as the testicles and its long projecting forecourt as the shaft". The outsized phallus of Roman art was associated with the god Priapus, among others. It was laughter-provoking, grotesque, or used for magical purposes. Originating in the Greek town of Lampsacus, Priapus was a fertility deity whose statue was placed in gardens to ward off thieves. The poetry collection called the Priapea deals with phallic sexuality, including poems spoken in the person of Priapus. In one, for instance, Priapus threatens anal rape against any potential thief. The wrath of Priapus might cause impotence, or a state of perpetual arousal with no means of release: one curse of Priapus upon a thief was that he might lack women or boys to relieve him of his erection, and burst. There are approximately 120 recorded Latin terms and metaphors for the penis, with the largest category treating the male member as an instrument of aggression, a weapon. This metaphorical tendency is exemplified by actual lead sling-bullets, which are sometimes inscribed with the image of a phallus, or messages that liken the target to a sexual conquest—for instance "I seek Octavian's asshole." The most common obscenity for the penis is mentula, which Martial argues for in place of polite terms: his privileging of the word as time-honored Latin from the era of Numa may be compared to the unvarnished integrity of "four letter Anglo-Saxon words". Cicero does not use the word even when discussing the nature of obscene language in a letter to his friend Atticus; Catullus famously uses it as a pseudonym for the disreputable Mamurra, Julius Caesar's friend ("Dick" or "Peter" might be English equivalents). Mentula appears frequently in graffiti and the Priapea, but while obscene the word was not inherently abusive or vituperative. Verpa, by contrast, was "an emotive and highly offensive word" for the penis with its foreskin drawn back, as the result of an erection, excessive sexual activity, or circumcision. Virga, as well as other words for "branch, rod, stake, beam", is a common metaphor, as is vomer, "plough". The penis might also be referred to as the "vein" (vena), "tail" (penis or cauda), or "tendon" (nervus). The English word "penis" derives from penis, which originally meant "tail" but