Different Symptoms for Different Causes of Pain. Orchialgia caused by infection is severe and even in cutting pain accompanied by fever with chilliness, reddened and swollen scrotum, and apparent tenderness. Most bacterial orchitis is caused by adjacent epididymal inflammation, so it is also called epididymo-orchitis.
From Wikipedia, the free encyclopedia. Agnatha (Greek, no jaws) is a superclass of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present (cyclostomes) and extinct (conodonts and ostracoderms) species. The group excludes all vertebrates with jaws, known as gnathostomes.he Agnatha are ectothermic or cold blooded, with a cartilaginous skeleton, and the heart contains 2 chambers.
Vertebrates are members of the larger phylum Chordata, and show all of the major chordate features at some point in their life cycles: notochord, dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.his arch is not present in other vertebrates, which may have lateral spines on the centrum instead of ventral spines. The jawless fish of today, the hagfish and lampreys, lack vertebral centra -- thus they are not vertebrates in the usual sense -- but they have neural arches on their notochords.