Über den feineren Bau des Mytiliden-Periostracum, erschlossen aus Der Optik

Abstract

In seiner Monographie der Mytiliden des Go]fes yon Neapel beschreibt LTST (1902) Mit sauren Farbstoffen (Eosin, Orange G) lassen sich die einzelnen, blaBgelblich erscheinenden Schichten --besonders nach vorausgegangener Diaphanolbehandlung --mehr oder minder stark f/£rben, mit Ausnahme

XV.—The Periostracum ofMytilus edulis

“…Early workers on the functions of the mantle margin, including List (1902) who reviewed their findings, assumed that the outer surface of the middle fold, to which the periostracum is attached, plays a major part in its secretion. This view was accepted by Field (1922), Haas (1935) and White (1937) but denied by Kessel (1944); observations by the present author agree entirely with Kessel's conclusion. The first formed and so outermost layer is very thin and is sometimes not distinguishable from the layer beneath.…”

“…Although usually clear when unstained, it is occasionally brown, and sometimes separated from the underlying layer by tiny vacuoles. Kessel (1940) reported the secretion of a layer between the first and second reported here. It disappeared as the periostracum moved outward marginally and he concluded that its substance became consolidated, losing the distinctive acidophilic and birefringent properties which he found it to have.…”

“…If they are not fixation artifacts, these corrugations may aid in the adhesion of the periostracum, though a transverse, rather than a radial orientation would seem to be more effective for this purpose. Kessel (1940) suggested that the outer layer differs chemically from the rest of the periostracum, since its intrinsic birefringence is positive, in contrast to the negative intrinsic birefringence of the other layers. The outer layer also differs from the bulk of the periostracum by colouring red in Mallory's triple stain.…”

“…3. The contents of the vacuoles, when unfixed, are apparently fluid, for in dried material the vacuoles appear air-filled (Kessel 1940). In sections of fixed material the contents take up both Alcian Blue and Ehrlich's hsematoxylin.…”

“…THE literature on periostracum has been reviewed by Haas (1935) and Kessel (1944). The present study of the periostracum of Mytilus edulis has been undertaken to elucidate further the process of periostracum formation in the Bivalvia.…”