On the Orbits of Singer Groups and Their Subgroups

We study the action of Singer groups of projective geometries (and their subgroups) on $(d-1)$-flats for arbitrary $d$. The possibilities which can occur are determined, and a formula for the number of orbits of each possible size is given. Motivated by an old problem of J.R. Isbell on the existence of certain permutation groups we pose the problem of determining, for given $q$ and $h$, the maximum co-dimension $f_q(n, h)$ of a flat of $PG(n-1, q)$ whose orbit under a subgroup of index $h$ of some Singer group covers all points of $PG(n-1, q)$. It is clear that $f_q (n, h) < n - \log_q (h)$; on the other hand we show that $f_q(n, h) \geq n - 1 - 2 \log _q (h)$.

Definition and revision of the Enoplognatha ovata (Clerck) group (Araneae: Theridiidae)

The monophyletic Enoplognatha ovata group is defined on the basis of the following synapomorphic characters: subapical first metatarsal trichobothrium, sclerotized and modified apex of the conductor in the male palpal bulbus, and strongly developed copulatory pockets in the female vulva. In the group the male conductor and the female epigynal openings together with the copulatory pockets form a coadapted functional unit which might prevent interspecific copulation. The hitherto known range of the group covers the western Palaearctic and, apparently through recent introduction by man, the eastern and western Nearctic. Three species are included: E. ovata (Clerck) (Palaearctic, Nearctic), E. latimana n. sp. (southern Middle Europe, Nearctic) and E. penelope n. sp. (Mediterranean). The characteristics of the species are described and discussed both at the individual and population levels.

Society of Physicians at Kazan University

Prof. A. I. Timofeev and Dr. V. V. Diakonov: Materials for the Study of Postpartum Infection. The authors have developed materials of the Obstetric Clinic of Kaz. State University for the period from 1900/01 up to 1925/26 inclusive and material of the Obstetrical Clinic of the State Institute for Advanced Training of Physicians for the period from 1920 to 1926 to find out the number of puerperal diseases during various periods of clinic activity. All material was divided into two groups: the first group covers the period from 1900 to 1919, the second from 1920 to the present.