author={Christopher M. Owen and Allyson L. Howard and Devin K Binder},
ON THE BICENTENNIAL of Darwin's birth, we describe the origin of the calcar avis and summarize the debate around this structure, which played a central role in the evolution debate in the mid-19th century. We performed a comprehensive review of relevant neuroanatomic literature, bibliographic sources, and 19th century primary sources. Once known as the hippocampus minor, the structure now known as the calcar avis is an involution of the ventricular wall produced by the calcarine fissure. A… 

Figures from this paper

Julius Caesar Arantius (Giulio Cesare Aranzi, 1530-1589) and the hippocampus of the human brain: history behind the discovery.
Julius Caesar Arantius is one of the pioneer anatomists and surgeons of the 16th century who discovered the different anatomical structures of the human body and originated the term hippocampus, which has become the most widely used in the literature.
A 2020 view of tension-based cortical morphogenesis
A differential expansion sandwich plus (DES+) revision to the original TBM model for cerebral cortical expansion and folding is proposed, and a cerebellar multilayer sandwich (CMS) model is proposed that can account for many distinctive features, including its unique, accordion-like folding in the adult.
A 2020 view of tension-based cortical morphogenesis
This article proposes a differential expansion sandwich plus (DES+) revision to the original TBM model for cerebral cortical expansion and folding, and proposes a cerebellar multilayer sandwich model that can account for many distinctive features, including its unique, accordion-like folding in the adult, and experiments are proposed to address its specific tenets.
Darwin's two competing phylogenetic trees: marsupials as ancestors or sister taxa?
Two competing phylogenetic diagrams on the origin of marsupials and placentals were outlined by Charles Darwin in a letter to Charles Lyell dated 23 September 1860 and are published here for the first time.
The Lateral Ventricles: A Detailed Review of Anatomy, Development, and Anatomic Variations
The anatomy and development of the lateral ventricles is reviewed, and several ventricular variations are discussed to prevent mistaking normal variants for pathology.
The protocadherin 11X/Y (PCDH11X/Y) gene pair as determinant of cerebral asymmetry in modern Homo sapiens
Annett's right‐shift theory proposes that human cerebral dominance and handedness are determined by a single “right‐shift” gene, which determines cerebral asymmetry by initiating the right shift in Homo sapiens.
Short-Term Bilateral Adrenalectomy: Biochemical and Morphological Alterations in the Rat Hippocampus
It is suggested that the early inflammatory components and loss of growth factors might contribute to the initiation of the biological cascade responsible for subsequent hippocampal neuronal cell death in the current neurodegenerative animal model.
Calcar avis…rara avis: A Flash Through Its History and Terminology
  • J. Barcia
  • Political Science
    Anatomical sciences education
  • 2019
Onomatology is the study of the formation, history and etymology of the terms. This discipline results of particular interest in anatomy since most of the anatomical terms have a specific meaning. As
Calcar avis


Hippocampus minor and man's place in nature: A case study in the social construction of neuroanatomy
The author considers the background of this controversy, the origin and fate of the term hippocampus minor, why this structure became central to the question of human evolution, and how Huxley used it to support both Darwinism and the political ascendancy of Darwinians.
Anatomy, metaphysics, and values: The ape brain debate reconsidered
Conventional wisdom teaches that Thomas Huxley discredited Richard Owen in their debate over ape and human brains. This paper reexamines the dispute and uses it as a test case for evaluating the
Richard Owen, Morphology and Evolution
This paper will examine Owen's evolutionary hypothesis and its connections with von Baer's idea of divergent development, and argue that special homology shows an evolutionary orientation insofar as it is a typically inter-specific character while serial homology is determined through an elementary usage of the categories of developmental morphology.
Huxley versus Owen: the hippocampus minor and evolution
  • C. Gross
  • Biology
    Trends in Neurosciences
  • 1993
Huxley: the devil's disciple
Ever since Leonard Huxley published his father's Life and letters (1900) and P Chalmers Mitchell wrote Thomas Henry Huxley (1900), there has been a steady production of Huxley biographies-one a
Thomas Henry Huxley (1825-1895) puts us in our place.
  • K. Weiss
  • Biology
    Journal of experimental zoology. Part B, Molecular and developmental evolution
  • 2004
Since his time the fossil record has greatly improved and the genetic 'revolution' has occurred, deepening the understanding of primate and human evolution in ways that would please Huxley: improved systematics relies heavily on genetic data, and molecular technologies are opening the authors' understanding of the genetic basis of complex traits of traditional anthropological interest-but in Ways that are thoroughly dependent on the fact of evolution.
Brain, Vision, Memory: Tales in the History of Neuroscience
The story of visual cortex and a case study in the social construction of neuroanatomy beyond striate cortex - how large portions of the temporal and parietal cortex became visual areas.
Accessory intraventricular prominence of the occipital horn of the lateral ventricle.
Besides its importance as a variation of normal ventricular morphological features, the close relationship of this accessory intraventricular prominence to the tail of the hippocampus should be kept in mind when intervening neurosurgically so that damage to the underlying commissural fibers can be avoided.
A history of neurosurgery in its scientific and professional contexts
Rasmussen has written an interesting and enjoyable account of some fascinating episodes in modern biology, and if the gulf between the theoretical analyses of the historians and philosophers of science, and the scientists who do the work is to be narrowed, more studies of this kind are needed.
Darwin's dangerous idea.
  • J. Launer
  • Education
    QJM : monthly journal of the Association of Physicians
  • 2002
Most educated people nowadays know that the authors share over 98% of their DNA with chimpanzees, but many humans may experience a frisson on learning this fact, which gives some sense of the existential horror that Darwin's contemporaries had to deal with.