Phylum Ctenophora (Comb Jellies)
Approximate Number of Species: 100
Largest: Lampocteis cruentiventer with a length of 0.52 feet (16cm)
Smallest: Minictena luteola with a length of 0.06 inches (1.5mm)
References:

Brusca RC & Brusca GJ (2003) Invertebrates (Sinauer Associates, Inc., Publishers, Sunderland, MA) 2nd Ed.
Harbison GR, Matsumoto GI, & Robison BH (2001) Lampocteeis cruentiventer gen. nov., sp. nov.: a new mesopelagic lobate ctenophore, respresenting the type of a new family (Class Tentacultat, Order Lobata, Family Lampoctenidae, Fam. Nov.). Bulletin of Marine Science 68(2):299-311.
Carre C & Carre D (1993) Minictena luteola, genre et espece nouveaux de Ctenophore Cydippida Mediterranean a cino types de colloblastes. Beauufortia 43(10):168-175.