31. During the courtship these snails spear the partner with a calcareous dart. 32. It is found only on calcareous substrates such as limestone. 33. It prefers a calcareous substrate, but also grows in neutral soils. 34. The northern region consists of calcareous sediments that have shown high permeabilities. 35. They secrete and inhabit a permanent calcareous tube attached to hard substrata. 36. This method made the supply of calcareous ore from the Sch�nberg unnecessary. 37. Elsewhere, deeper limestone soils support a diversity of calcareous grassland species. 38. Soils are either calcareous ( neutral or somewhat alkaline ) or acidic. 39. The skeleton is composed of many calcareous ossicles and spicules. 40. In this lake, extensive silty calcareous , glacilimnic layers were deposited.
