The manus of the Narwhal, Monodon monoceros L.

• Published in: Proceedings of the Zoological Society of London
• Main Author: Eales, N. B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1954
• Subjects: Monodon monoceros; narwhal*
• Online Access: http://dx.doi.org/10.1111/j.1469-7998.1954.tb07777.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1469-7998.1954.tb07777.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1954.tb07777.x; https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1954.tb07777.x

S ummary The flipper of the Narwhal has been investigated in foetal and adult stages, with special reference to the carpus. In the foetus, radiale, intermedium and ulnare, a single centrale, trapezoid, magnum and separate distal carpals 4 and 5 are present. There is no trace of a pisiform or of a trapezium. The centrale fuses with the intermedium. Distal carpals 4 and 5 unite to form an uneiform. In the adult there are three bones in the distal row. In the allied Delphinapterus (adult) the form of the flipper is similar, but the trapezoid is missing, as it is in Phocaena (Phocaenidae). In the Delphinidae, as illustrated by Globiocephala , trapezoid, magnum and uneiform are present. In broad‐handed whales (Monodon, Delphinapterus, Phocaena) the number of phalanges decreases with age, in narrow‐handed whales this number increases as the whale matures. The carpus of whales is of the interlocking type. A centrale has now been found during development in all mammals except some ungulates. Whales are the only mammals retaining traces of separate fourth and fifth distal carpals.