Monograph on the Lias Ammonites of the British Islands. Part Seventh—Description of Species. Pages 441–480; Plates LXXVIII–LXXXVII
Monograph on the Lias Ammonites of the British Islands. Part Seventh—Description of Species. Pages 441–480; Plates LXXVIII–LXXXVII
复制标题
关于不列颠群岛的利亚斯菊石的专着，第 7 部分——物种描述，第 441-480 页；图版 LXXVIII-LXXXVII。
DOI：
10.1080/02693445.1884.12027987
复制
发表时间：
1884
影响因子：
5.5
通讯作者：
Thomas. Wright
中科院分区：
文献类型：
--
作者：
Thomas. Wright
A.亲和力和lJi。好吧哈波切拉斯·莱维索尼与哈普有很强的联系。bifrons，仍然是外壳的构建呈现重要的差异点。在哈普。Levisoni的壳层较厚，肋的风格不同;侧槽，将肋的两侧分开，并在Harp中产生外肋的一半和内光滑的一半。bifrons，是缺席的竖琴。莱维索尼在竖琴中，虹吸区的形式也是不同的。bifrons我们有一个小龙骨与凹槽的每一方，而在竖琴。Levisoni有一个更厚和更突出的龙骨，以及在隆突两侧的两个侧沟的缺失。这两个物种的形态也是不同的。在早期的生活中，Harpoceras Levisoni的外壳将其比作一个。Arietites;它有厚，直costre，在角knobbed，和一个虹吸区与坚固的龙骨，和两个侧槽，像Ariet。obtusus;然而，随着贝壳的进化，所有这些字符都变得过时了。只有通过分解大的标本并找到细胞核，真相才是真实的！lled.当所有这些结构特征上的差异被公平地考虑时，它们足以证明分离成两个不同的物种是合理的。
A. ffinities and lJi. fferences.-Ha'rpoceras Levisoni has strong affinities with Harp. bifrons, still the build of the shells presents important points of difference. In Harp. Levisoni the shelly laminre are thicker, and the style of costation different; the lateral groove which divides the costre on the sides, and produces an outer costated half and an inner smooth half in Harp. bifrons, is absent in Harp. Levisoni. The form of the siphonal area is likewise different, in Harp. bifrons we have a small keel with grooves on each side, whilst in Harp. Levisoni there is a thicker and more prominent keel, and an absence of the two lateral furrows on each side of the carina. The morphology of the two species is likewise different. In early life the shell of Harpoceras Levisoni likens it to that of an. Arietites; it has thick, straight costre, knobbed at the angle, and a siphonal area with stout keel, and two lateral grooves, like Ariet. obtusus; all these characters, however, become obsolete as the evolution of the shell proceeds. It is only by breaking up large specimens and finding the nucleus, that the truth is reve! lled. When all these differences in the structural characters are fairly considered, they are sufficient to justify the separation into two distinct species.