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.
Characteristics of the Five Vertebrate Groups. Fish. The body of the fish is covered in scales and has fins attached to help it move through the water. Fish breathe using gills which take oxygen out of the water. When male and female fish mate, the eggs often meet the sperm in the water. This is called external fertilization. Examples of fish are the herring, which lives in the sea, and the pike which is a freshwater fish.