Etymology of sponge types

Sponges (Porifera) come in three body forms - asconoid (vase-shaped), syconoid (pleated vase), and leuconoid (network of chambers, like bath sponges). I was wondering what the etymology of these terms was. Since they are scientific terms, I'm assuming Classical origin, but I don't know enough Greek or Latin to recognize the roots.

Solution 1:

asco- prefix Lt. < Gk. ἀσκός

Websters: Modern Latin; from Classical Greek askos, wineskin, bladder

syco- prefix Lt. < Gk.

Wordinfo: fig sweet, hollow, pear-shaped, multiple fruit that has numerous tiny seedlike fruits that are eaten fresh or preserved or dried
Reference.com 1885–90; < Neo-Latin < Greek sŷkon fig

leuco- prefix Lt. < Gk.

< Neo-Latin < Greek leukón, noun use of neuter of leukós white

-oid

Wiktionary: Of similar form to, but not the same as. Having the likeness of. Suffix appended to various words to make an adjective form.
human → humanoid
sterol → steroid
planet → planetoid

Solution 2:

My Zoology text (Hickman et al., 17th ed.) stated that the name comes from historical accident: the earliest forms of leuconoids that were analyzed happened to be white. If true, it's one more example of scientific nomenclature that should have probably been improved at some point along the way.