DISTRIBUTION OF ARION HORTENSIS S.S. AND ARION DISTINCTUS IN NORTHERN SWITZERLAND

The distribution of the sibling slug species Arion hortensiss.s. and Arion distinctus in Northern Switzerland is described.In the sampled area, both species were almost equally abundantand their distributions overlapped. Most of the sampled sitescontained both species. Arion hortensis s.s. is more commonin Switzerland than previously known, and its range extendsmore towards the east of Switzerland. Arion hortensis s.s. wasmore abundant in gardens than in the other habitats sampled.At sites where only A. distinctus occurred, the form with abipartite oviduct prevailed. At sites where both species werepresent, the form of A. distinctus with a tripartite oviductwas more common than the form with a bipartite oviduct. In captivity,one specimen of A. distinctus mated with one A. hortensis s.s.,as indicated by a spermatophore of A. distinctus that was found withinthe atrium of one A. hortensis s.s. A majority of the specimens couldby assigned to the correct species by their colouration, buta safe distinction between A. hortensis s.s. and A. distinctusis only possible using characters of the reproductive system. (Received 4 July 2000; accepted 19 September 2000)     

ORIGINS OF SOLANUM LASIOCARPUM AND S. REPANDUM

Solanum candidum of tropical America is very similar to S. lasiocarpum of southeastern Asia and S. sessiliflorum, a wild and domesticated plant of the Amazon basin, is very similar to S. repandum, a weed and domesticated plant of Oceania. Artificial hybrids between S. candidum and S. lasiocarpum are fertile, and it is postulated that S. lasiocarpum resulted from a Spanish introduction of S. candidum to Asia. Hybrids between S. repandum and S. sessiliflorum show considerable reduction in fertility and abnormalities at meiosis, whereas hybrids of both S. candidum and S. lasiocarpum with S. repandum are fertile. It is concluded that it is likely that S. repandum did not arise from S. sessiliflorum but from S. lasiocarpum or S. candidum. This would mean that the similarity of S. repandum to S. sessiliflorum results from convergence.     

桂西和黔南中三叠世珊瑚

文内描述中三叠世安尼阶(Anisian)珊瑚化石分别采自桂西田阳板纳组和黔南贵阳青岩青岩组。板纳组珊瑚群中建立Pentasmilia guangxiensisgen.etsp.nov.,该新属种有5条第一周期原生隔片甚至有5条第二周期后生隔片,以此不同于有6条第一周期原生隔片和有6条第二周期后生隔片的石珊瑚类(scleractinians)的珊瑚。产于板纳组的另一新属种Radiophyllia astylatusgen.etsp.nov.,其隔片的排列格式与前人归纳的隔片周期插入示意图甚似,但它却发生在中生代最早期(Anisian)珊瑚的骸体内。文中还对青岩组的Pamiroseris silesiaca作了重新描述。