Kidney stones are composed of crystals that usually form in the kidneys or ureters (the tubes that carry urine from the kidneys to the bladder); most are very small but some can be as big as a golf ball. Most small stones cause intense flank and pelvic pain as they irritate the ureters as they pass through them.idney stones are composed of crystals that usually form in the kidneys or ureters (the tubes that carry urine from the kidneys to the bladder); most are very small but some can be as big as a golf ball. Most small stones cause intense flank and pelvic pain as they irritate the ureters as they pass through them.
Osteichthyes /ËÉstiËËÉªkÎ¸i.iËz/ , also called bony fish, are a taxonomic group of fish that have bone, as opposed to cartilaginous, skeletons.The vast majority of fish are osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, and over 435 families and 28,000 species.It is the largest class of vertebrates in existence today.Osteichthyes are divided into the ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii).The oldest known fossils of bony fish are about 420 million years ago, which are also transitional fossils, showing a tooth pattern that is in between the tooth rows of sharks and bony fishes.t is the largest class of vertebrates in existence today. Osteichthyes are divided into the ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii).
Osteichthyes. Class Osteichthyes (the bony fish) is the largest class of vertebrates with over 20,000 species. The total numbers of fishes exceed that of all other kinds of vertebrates combined.