Endolobus is an extinct genus from the nautiloid order, Naulilida which includes Nautilus

Nautilus

Nautilus is the common name of marine creatures of cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in two genera, the type of which is the genus Nautilus...

found living today. Endolubus is ncluded in the family Koninckioceratidae which is part of the superfamily Taintocerataceae. (Kümmel 1964.K424)

The shell of Endolobus is an evolute spiral with whorl sections subelliptical; broadly rounded ventrally, narrowly rounded laterally, and slightly impressed dorsally (ibid) . There are low nodes on the flanks and the suture is slightly sinuus but with a prominent dorsal lobe. (Inside lobe, or endo-lobus) The siphuncle is small, subcental, and orthochoantic.

Endolobus has a range from the Lower Carboniferous

Carboniferous

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

 (U Miss) to the Lower Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

and has been found in different locations in North America and eastern Europe.

Nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.