The protoconch is not different from that of Murchisonella. In the teleoconch whorls there is a conspicuous difference: in Murchisonella the whorls are divided into two parts with sometimes very different sculpture or shape due the presence of a step, cord or more elevated area between the two parts. In some species of Murchisonella (for example M. modesta spec, nov.) there may be no physical feature separating the two areas but under magnification the growth lines clearly have different directions in the upper and lower parts of the whorls as is also reflected in the shape of the outer lip. In the subsutural area there is a curved line or subsutural sinus, while the outer lip protrudes evenly below the sinus. In Pseudoaclisina the outer lip (and the growth lines) forms a continuous curve with no inflection and is prosocline on the upper part of the whorl and opisthocline below.