Balanoglossus in Mashail Island described it as a worm-like holothurian. The discovery of gill-slits in this animal by Kowalewsky (1865) led to creation of a special class Enteropneusta by Gegenbaur (1870). Bateson (1885) included them in Phylum Chordata. Hyman (1959), however, placed them near Echinodermata and gave Hemichordata a status of an independent phylum. This simple organism shows affinities with several diverse groups. Balanoglossus is a tuberculos or burrowing and exclusively marine animal. It is found in shallow waters between tide marks along the coast of warm and temperate oceans. Balanoglossus clavigerus is a U-shaped excavated in a sandy bottom Nemertines
Lattice of subgroups of the form Z × Z, generated by pairs of order-two elements. The lattice formed by these ten subgroups is shown in the illustration. This example also shows that the lattice of all subgroups of a group is not a modular lattice in general. Indeed, this particular lattice contains the forbidden "pentagon" "N" as a sublattice. For any "A", "B", and "C" subgroups of a group with "A" ≤ "C" ("A" subgroup of "C") then "AB" ∩ "C" = "A(B ∩ C)"; the multiplication here is the product of subgroups. This property has been called the "modular property of groups"