Salvi.. 111. Sewertzoff. Lo sviluppo ed il valore della cosi detta tasca di Seesel. Arch. 112. Beitrag zur Entwickelungsgeschichte des Wirbelthierschädels. Anat. Anz., Bd. 13, 409-425. 1897. Smirnow. 113. Strong. Ueber freie Nervenendigungen im Epithel des Regenwurms. Anat. 114. The Cranial Nerves of Amphibia. A Contribution to the Vertebrate Nervous System. Jour. Morph., Vol. 10, 101-230 1895. 115. The Cranial Nerves of Squalus acanthias. Abstract. Science N. S., Vol. 17, No. 424. 1903. Studnicka. 116. Ueber den feineren Bau der Parietalorgane von Petromyzon marinus. Sitzungsber. d. k. böhm. Gessel. d. Wiss. Math.-nat. Cl., 1898, 4 PP. Tullberg. 117. Das Labyrinth der Fische, ein Organ zur Empfindung der Wasserbewegungen. Bihang till K. Svenska Vet.-Akad. Handl., Bd. 28, Afd. 4, p. 21-25. 1903. Waters. 118. van Wijhe. Primitive Segmentation of the Vertebrate Brain. Quart. Jour. 119. Uber die Mesodermsegmente und die Entwickelung der Nerven des Selachierkopfes. Amsterdam. 1882. 120. Beiträge zur Anatomie der Kopfregion des Amphioxus lanceolatus. Petrus Camper, Deel 1, Afl. 2. 1900. Wilson. 121. The Embryology of the Sea Bass (Serranus atrarius). Bull. U. S. Fish Com., Vol. 9, 209-277. 1891. Wilson and Mattocks. 122. The Lateral Sensory Anlage in the Salmon. Anat. Anz. Bd. 13, 658-660. Wlassak. 123. 1897. Kleinhirn des Frosches. Arch. f. Anat. u. Physiol., Physiol. Abth. Zimmerman. Locy. 124. Ueber die Metamerie des Wirbelthierkopfes. Verhdl. d. Anat. Ges. 5. Vers. München, 1891, 107-113. 125. A Contribution to the Structure and Development of the Vertebrate Strong. 126. Hoffmann. Review of Locy No. 86. Jour. Comp. Neur. and Psych., Vol. 14, 127. Zur Entwickelungsgeschichte des Selachier Kopfes. Anat. Anz., Bd. 9, 638-653. 1894. DESCRIPTION OF FIGURES. Abbreviations. 1, 2, 3, etc.-mesodermic somites of VAN WIJHE. i, ii, iii, etc.- neuromeres of Locy. A- praeoral entoderm connected with the origin of somite I and the anterior head cavity. a-l.—area of the primitive neural plate which gave rise to the acustico-lateral Hypothetical. system. au. v.-auditory vesicle placode. b1, b2, etc.-branchial clefts. B1, B2, etc.-branchial arches. ch.-notochord. cil. g.-ciliary ganglion. hab.-ganglion habenulae. h. l.-portion of common acustico-lateral placode in selachians which goes to form the head lines. int. arc.-internal arcuate fibers from cutaneous centers. L-nerve of Locy (Fig. 10) and its center (Fig. 7). 1. l.-portion of acustico-lateral placode which forms the lateral line. s. s. somatic sensory column. S. v. secondary vagus tract. sy. g. sympathetic ganglion. T-hypothetical center for the nervus thalamicus (visceral). t. b-t.-tractus bulbo-tectalis. t. l-b.-tractus lobo-bulbaris. t. t-b.-tractus tecto-bulbaris. t. t.l.-tractus tecto-lobaris. t. o.-tractus opticus. t. o-h.-tractus olfacto-habenularis. t. s.th. - tractus sacco-thalamicus. tr. n.-trunk nerve. An arrow point in Fig. 8 indicates the hypothetical margin of the primitive neural plate; in Fig. 10 indicates the anterior end of the brain. PLATE I. Figures 1-7 illustrate the longitudinal zones of the brain and the relation of the brain commissures to them. Fig. 7 is a median sagittal section of the brain of a fish on which are projected the zones of the right half of the brain. The location of the various decussations is also indicated by symbols which are explained on the plate. The places of exit of the nerve roots are indicated by the usual Roman numerals. The lateral line roots arise near to or above VIII. The olfactory centers have been shown in the same shading as the visceral sensory centers in the medulla oblongata. The secondary vagus nucleus and the hypothetical nucleus of the nervus thalamicus are also shown in the same way. The ventro-mesial zone, marked by small circles in this and Fig. 1, is made up of cells which closely surround the mid-ventral furrow of the ventricle. These cells form important nuclei in the inferior lobes, the nucleus thaeniae, the corpus interpedunculare and nucleus of MEYNERT'S bundle (and possibly the lower olive in fishes). This area corresponds to or includes the Bodenplatte distinguished by HIS in the embryonic brain. Fig's. 1-6 represent cross sections at the levels indicated by the reference lines. More structures are shown in some of the figures than would appear in an actual section. Fig. 1.-Section through the superior commissure, ganglia habenulae, thalamic nucleus of the somatic motor fasciculus, and the inferior lobes in front of the saccus vasculosus. The position of several fiber tracts is shown. Fig. 2.-Through the tectum opticum, dorsal decussation, ansulate commissure, and the nucleus of N. III. Fig. 3.-Through the cerebellum and the root of N. V. Both somatic and visceral decussations in the cerebellum are shown. Fig. 4.—Through the root of N. IX. The difference in the course of the secondary tracts from the somatic sensory and the visceral sensory centers is shown. Fig. 5.--Through the commissura infima HALLERI. Fig. 6.-Through the root of a spinal nerve and showing the dorsal and ventral decussations of the spinal cord. PLATE II. Fig. 8, A, B, C.--Three diagrams to illustrate the hypothesis of the origin of the acustico-lateral system from the margin of the neural plate. Each functional division of the nervous system is represented by one cell and fiber. Several general cutaneous ganglion cells which are destined to form the acustico-lateral ganglion are shown. The mesoderm and somatic motor nerve are omitted from C, because by the time the acustico-lateral system has reached the grade of development represented, somite 4 no longer forms a myotome. PLATE III. Fig. 9, A-G.-Seven outline diagrams to illustrate the hypothesis of the origin of the eye by modification of a general cutaneous ganglion and its corresponding centers. The retinal area is indicated by a row of large dots. The relation of the inner wall of the optic vesicle to the choroid plexus, spoken of in the text, is shown in F and G. A comparison of Fig. 9 F with Fig. 4 will show the similarity of position between the retina and acusticum. It will also show that the optic tract fiber from the retina takes a course corresponding to that of the secondary fiber (internal arcuate) from the cutaneous nucleus. PLATE IV. Fig. 10.-A diagram of segmentation in a generalized vertebrate head. In its general features the diagram follows Petromyzon more closely than any other form. So, the number of the gill clefts, their position relative to the somites, the position of the auditory vesicle, and the formation of hypobranchial muscles from myotome 10 and following, are taken from Petromyzon. The neuromeres, the nerve of Locy, the nervus thalamicus, the relation of the head lines to the auditory vesicle, and the praeoral entoderm are taken from selachians. The sensory nerve roots are represented as retaining their attachment to the dorsal surface of the neural tube where they were formed from the neural crest. The segmental position of these roots is about that which they have in the embryo of Petromyzon, except the root of N. X, which has been shifted back a little farther than it is in Petromyzon. The general cutaneous nerve shown in dotted outline over somite 6 is the Vagusanhang of HATSCHEK in Ammocoetes and the nerve which unites with the vagus root in the embryo of selachians. The position of the viscero. motor nuclei somewhat caudal to the several roots is indicated. The viscero-motor nucleus of the vagus and accessorius is shown as a single large nucleus extending through two segments. It might more properly have been continued caudally until it came into connection with the viscero-motor nucleus of the trunk nerve. The accessorius nerve is not shown. The somatic nucleus and root are shown for all the somites except somite 4, where they are shown in dotted outline. The nerves for both somites 4 and 5 are absent in Petromyzon. Probably both are present in Bdellostoma (a'v and 'v of FÜRBRINGER). It is possible that one or both of these has joined with N. VI in gnathostomes. LITERARY NOTICES. Loeb, Jacques. Studies in General Physiology. Chicago, The University of Chicago Press, 1905. Part I. xiii + 423, Part II. xi + 425-782. These volumes contain a series of thirty-eight of the author's papers, all of which are reprinted and most of which originally appeared in German. Within the field of comparative neurology and psychology we note the following papers of the series: "The Heliotropism of Animals and its Identity with the Heliotropism of Plants; Further Investigations on the Heliotropism of Animals and its Identity with the Heliotropism of Plants; On Instinct and Will in Animals; Geotropism in Animals; The Artificial Transformation of Positively Heliotropic Animals into Negatively Heliotropic and vice versa; Contributions to the Brain Physiology of Worms; Has the Central Nervous System Any Influence upon the Metamorphosis of Larvae ?; On the Theory of Geotropism." Since the various papers of these volumes received review notice when first published it will suffice, while announcing the fact that they are now available in English, to call attention to the author's scientific life-purpose and the relation which these papers bear to it. From the preface we quote, "a single leading idea permeates all the papers of this collection, namely, that it is possible to get the life-phenomena under our control, and that such a control and nothing else is the aim of biology." According to their method of approach to this goal of research the papers fall into three groups: first, those which are concerned with the control of movement; second, those which deal with the control of regeneration and the determination of organ-formation; third, those which concern the control of the development of the egg. It is needless to say that Professor LOEB has made great strides toward the accomplishment of his scientific purpose. His work is of great importance; indeed, even when it has followed wrong paths, it has been of value for its stimulating and research-impelling influence. R. M. Y. |