Cyrtochoanite

81 ) is inclined to regard it as a cyrtochoanite and points out that its narrow siphuncle indicates that it is not a holochoanite . With the exception of this single minute form , which is imperfectly known , even questionable[…]

Source: wiktionary

Although it is probable that this form is an orthochoanite and the segments of its siphuncle are cylindrical , it may be a cyrtochoanite with fusiform or even globular siphuncular segments . Until the nature of its siphuncle is[…]

Source: wiktionary

The writer agrees with Teichert that Lambeoceras is a cyrtochoanite rather than an orthochoanite as suggested by Troedsson . SOME MIDDLE CARBONIFEROUS AMMONOIDS AND THEIR STRATIGRAPHICAL SIGNIFICANCE BY A. ABSTRACTS 1965.

Source: wiktionary