Horse outward similarity is an unreliable measure of relatedness. Besides the horse, there are six other species of genus "Equus" in the Equidae family. These are the ass or donkey, "Equus asinus"; the mountain zebra, "Equus zebra"; plains zebra, "Equus quagga"; Grévy's zebra, "Equus grevyi"; the kiang, "Equus kiang"; and the onager, "Equus hemionus". Horses can crossbreed with other members of their genus. The most common hybrid is the mule, a cross between a "jack" (male donkey) and a mare. A related hybrid, a hinny, is a cross between a stallion and a jenny (female donkey). Other hybrids include the zorse,
Titus Sextius Africanus Titus Sextius Africanus Titus Sextius Africanus was a Roman senator who was deterred by Agrippina the Younger from marrying Junia Silana. He served as a suffect consul in 59 AD. In 62 AD, he took the census in the provinces of Gaul, together with Quintus Volusius Saturninus and Marcus Trebellius Maximus. Saturninus and Africanus were rivals, and both hated Trebellius, who took advantage of their rivalry to get the better of them. His name occurs in a fragment of the Fratres Arvales. Titus Sextius Cornelius Africanus, who served as a consul with Trajan in 112 AD, was related to Africanus.