张春桥和李曼村:amoecetes什么意思

七鳃鳗在年幼时的叫法

It's not "amoecetes" it's "ammocoetes"

A lamprey (amoecetes=lamprey) is a jawless fish with a toothed, funnel-like sucking mouth, with which most species bore into the flesh of other fishes to suck their blood. In zoology, lampreys are not considered to be true fish because of their vastly different morphology and physiology.

Lampreys live mostly in coastal and fresh waters, although at least one species, Geotria australis, probably travels significant distances in the open ocean, as is evidenced by the lack of reproductive isolation between Australian and New Zealand populations, and the capture of a specimen in the Southern Ocean between Australia and Antarctica. They are found in most temperate regions except Africa. Their larvae have a low tolerance for high water temperatures, which is probably the reason that they are not found in the tropics. Outwardly resembling eels in that they have no scales, an adult lamprey can range anywhere from 5 to 40 inches (13 to 100 centimetres) long. Lampreys have one or two dorsal fins, large eyes, one nostril on the top of their head, and seven gills on each side. The unique morphological characteristics of lampreys, such as their cartilaginous skeleton, means that they are the sister taxon (see cladistics)of all living jawed vertebrates (gnathostomes) and are not classified within the Vertebrata itself. The hagfish, which superficially resembles the lamprey, is the sister taxon of the lampreys and gnathostomes (a clade termed the Craniata).

Basic external anatomy of the Lamprey
Mouth of a Sea LampreyLampreys begin life as burrowing freshwater larvae (ammocoetes). At this stage, they are toothless, have rudimentary eyes, and feed on microorganisms. This larval stage can last five to seven years and hence was originally thought to be an independent organism. After these five to seven years, they transform into adults in a metamorphosis which is at least as radical as that seen in amphibians, and which involves a radical rearrangement of internal organs, development of eyes and transformation from a mud-dwelling filter feeder into an efficient swimming predator, which typically moves into the sea to begin a predatory/parasitic life, attaching to a fish by their mouths and feeding on the blood and tissues of the host. In most species this phase lasts about 18 months. Whether lampreys are predators or parasites is a blurred question.

Not all lampreys can be found in the sea. Some lampreys are landlocked and remain in fresh water, and some of these stop feeding altogether as soon as they have left the larval stage. The landlocked species are usually rather small.

To reproduce, lampreys return to fresh water (if they left it), build a nest, then spawn, that is, lay their eggs or excrete their semen, and then invariably die. In Geotria australis, the time between ceasing to feed at sea and spawning can be up to 18 months long—surely one of the most remarkable endurance events in the animal kingdom.

Recent studies reported in Nature suggest that lampreys have evolved a unique type of immune system with parts that are unrelated to the antibodies found in mammals. They also have a very high tolerance to iron overload, and have evolved biochemical defenses to detoxify this metal.

source: http://en.wikipedia.org/wiki/Ammocoetes

Some other photos of lamprey/ammocoetes
http://miseagrant.umich.edu/photos/ais/lamprey.html