Kovács I. (szerk.): A Magyar Természettudományi Múzeum évkönyve 78. (Budapest 1986)

Farkas, H.: The variability problem of Schuleridea (Aequacytheridea) perforata (Roemer, 1838) (Ostracoda; Eocene)

to the "Okular-Netzmikrometer" of a microscope; its base line subtends at one or two points the bottom margin of the shell, while the length of the shell fills completely the breadt of the network. The figure is not a completely true representation of the micrometer mesh, since the one I used contains 400 squares, these squares formed by the thicker lines being further subdivided into four smaller squares by thin lines. A glance at the figure reveals that one can read on the network micrometer the distance of a given point of the shell outline from the base line, that is every point of the outline can be marked in the screen of coordinates. This technique can be applied, with smaller to greater alterations, to a considerable part of the Ostracod species. Difficulties arise mainly in case of heavily ornamented species. The outline of the shell of the species I studied bisects sharply every line of the micrometer, and since the points of the outline fall pratically in one plane, the points of intersection can be measured with precision under the microscope. The possibility of an unequivocal graphic representation is therefore also given. There are several possibilities of notations by numerals. As it can also be seen in the figure, I took measurement readings with respect to the "thin lines" only at these defining distances of 5% and 95%. I measured the distance of the dorsal (top) and the ventral (bottom) lines from the base along points representing 0, 5, 10,20, 30, 40, 50, 60, 70, 80, 90, 95, and 100 per cents. For abbreviations, I used the following symbols: r aa right shell 1 = left shell a = distance from the base t = "top" or dorsal line of the shell b = "bottom" or ventral line of the shell In this sence, e. g. "rat 80 mean = 53.50" has the following interpretation: "At 80 per cent of the maximum length of the right shell the distance of the upper line of the shell from the base line is 53.50% of the entire length as referred to the mean of the population". As for the interpretation of the tables, I believe that they afford easy survey, the further details in words seem superflous in this place. When consulting the figures it will also appear that it is in the case of those very 0 and 100 coordinates that the data cannot be measured with exactness, as the outline of the shell not so much intersects as it arcuately touches (is tangential to) the base coordinates. References FARKAS, H. (1974) : Morphological analysis of Ostracods (Crustacea), I. The problem of „Cyprodipsis vidua and C. obesa". — Acta zool. hung. 20 (1-2): 33-46. MÉHES, GY. (1936): Budapest vidékének eocén Ostracodái. — Geol. hung., ser. Pal. 12: 1-64. MONOSTORI, M. (1985): Eocene Ostracods from the Dorog Basin. — Akadémiai Kiadó, Budapest 214 p. Author's address : DR. HENRIK FARKAS Department of Archive of Natural History Hungarian Natural History Museum Budapest, pf. 222 H-1476