Non marine Mollusca from fossil horizons in Java with special reference to the Trinil fauna

CONTENTS 1. Preface . . . 83 2. Introduction . . . 85 3. Synopsis of the strata yielding fossil non-marine Mollusca . . . 86 4. Systematic survey of the shells . . . 93 5. Ecological valuation of the deposits . . . 160 6. Malacological evidence for the determination of the age of the beds . . . 166 7. Literature . . . 177 PREFACE The following report is based in the first place on the important collection of fossil non-marine mollusca made by Prof. Eug. Dubois at Trinil and vicinity (East Java) during excavations in the years 1890 to 1900. It is the very same region where Prof. Dubois discovered the famous remains of his Pithecanthropus erectus, a man-like primate. The structure and affinities of this fossil being have not only roused the general interest of naturalists and occupied them for almost the last 40 years, but they appeal also to the imagination of the whole mankind in past, present and future. The entire Dubois Collection is now preserved at Leiden, as a special part of the collections of the Rijksmuseum van Natuurlijke Historie, under the immediate supervision of the collector. I take great pleasure in expressing to Prof. Dubois my infinite gratitude for entrusting to me the malacological part of his extraordinary collection. His benevolent interest during the progress of the work was amply demonstrated by various suggestions and useful advice. My acknowledgments are also due to the late Dr. J. J. A. Bernsen O. F

On the occurrence of a Cyclohelix on Java

In 1921 's Rijks Museum van Natuurlijke Historie received from Jhr. W. C. VAN HEURN a collection of landmollusca, collected by him at about 1600 m. altitude in the Malabar Mounts, West Java. Amongst 19 Cyclophorus rafflesi (Brod. & Sow.), 38 Cyclophorus perdix f. zollingeri (Mouss.) and 1 Dyakia rumphii (v. d. Busch) there was one Cyclohelix. Now the truth is that of this genus no representative has been hitherto recorded from Java. KOBELT (Cyclophoridae in: Tierreich, 1902, p. 144—146) mentions the following species in all: crocatus (Born) = turbo (Chemn.), denselineatus (Pfr.), foliaceus (Chemn.) and nicobaricus Pfr. all from the Nicobar Islands and leai (Tryon) from the Andaman Islands. Afterwards FULTON described C. kibleri from Nias Id. (Ann. Mag. Nat. Hist. (7) Vol. 19, 1907, p. 156, pl. 10, fig. 4). One is inclined to ask how it comes about that MÖRCH (Journ. de Conch. Vol. 20, 1872, p. 316) and KOBELT (Nachr. Blatt, Vol. 31, 1899, p. 134 and Tierreich 1902, p. 144) consider C. turbo identical with C. crocatus as the two species do not agree in the least either in shape or in colour, while moreover the habitat of crocatus is altogether unknown (cfr. PFEIFFER in Mart.-Chemn. N. Syst. Conch. Cab. Band I, Abt. 191, 1849, pl. 19, fig. 4, 5 with BORN, Test. Mus. Vindob. 1780, pl. 12, fig. 11 and 12). Thus it is clear that crocatus must be dropped from the synonymy of Cyclohelix turbo. In the second place KOBELT (Tierreich 1902, p. 144) omits the record of C. turbo from Sumatra 1) by SOWERBY (Thes. Conch. Vol. I, 1843, p. 116, pl. 25, fig. 102, 103) afterwards quoted by PFEIFFER (I.c. p. 141

Explicit Universes for the Calculus of Constructions

The implicit universe hierarchy implemented in proof assistants such as Coq and Lego, although really needed, is painful, both for the implementer and the user: it interacts badly with modularity features, errors are difficult to report and to understand. Moreover, typechecking is quite complex

Pure type systems in rewriting logic: Specifying typed higher-order languages in a first-order logical framework

Dedicated to the memory of Ole-Johan Dahl Abstract. The logical and operational aspects of rewriting logic as a logical framework are tested and illustrated in detail by representing pure type systems as object logics. More precisely, we apply membership equational logic, the equational sublogic of rewriting logic, to specify pure type systems as they can be found in the literature and also a new variant of pure type systems with explicit names that solves the problems with closure under α-conversion in a very satisfactory way. Furthermore, we use rewriting logic itself to give a formal operational description of type checking, that directly serves as an efficient type checking algorithm. The work reported here is part of a more ambitious project concerned with the development of the open calculus of constructions, an equational extension of the calculus of constructions that incorporates rewriting logic as a computational sublanguage. This paper is a detailed study on the ease and naturalness with which a family o