Observations upon the American representative of macrostomum tuba

✍ Scribed by William A. Kepner; M. W. Stiff

• Book ID: 102903331
• Publisher: John Wiley and Sons
• Year: 1932
• Tongue: English
• Weight: 567 KB
• Volume: 54
• Category: Article
• ISSN: 0362-2525
• DOI: 10.1002/jmor.1050540107

✦ Synopsis

Abstract

What appears to be a variety of Macrostomum tuba has been described in this paper. There is but a single retinula in each eye. This visual cell displays three regions: rhabdome, ellipsoid, and myoid, as does a vertebrate's retinula. Moreover, the accessory pigment associated with the retinula of M. tuba is applied to the rhabdome and not to the ellipsoid and myoid; this likewise is similar to the distribution of the pigment about the vertebrate's retinula. An analogy, therefore, may be drawn between the visual cell of the rhabdocoele and that of the vertebrate. This is so strong as to suggest homology. Several features peculiar to this variety are: first, the chitinous, distal ring of the penis; second, the fact that shell and yolk droplets seem to be elaborated by each cell destined to become an oocyte.