What is "metabaltoceras"

Metabaltoceras, first described by Rousseau Flower in 1964, is a fossil cephalopod genus in the family Baltoceratidae, with a small, slender, fairly fusiform shell, and a large empty siphuncle in contact with the ventral surface. The siphuncle is achoanitic, having virtually no septal necks, segments formed all but entirely by connecting rings. Shells are generally straight, beginning with a subcircular cross section in the adapical portion but becoming faintly depressed adorally (toward the front). Sutures are straight and transverse except ventrally, where they produce deep, prominent lobes.