Page:Encyclopædia Britannica, Ninth Edition, v. 16.djvu/723

Rh O L M O L 695 The embryonic cells continue to divide, and form an oval vesicle containing liquid (fig. 149); within this, at one pole, is seen the mass of invaginated cells (fig. 150, hy). These invaginated cells are the arch-enteron ; they proliferate and give off branching cells, which apply themselves (fig. 150, C) to the inner face of the vesicle, thus forming the meso- Fio. 152. Diagram of embryo of Pisidium in the same stage as E in fig. 151. TO, mouth ; /, foot ; ph, pharynx ; gs, met-enteron ; pi, rectal peduncle or pedicle of invagination ; shs, shell-gland. (From Laukester.) blast or coelomic outgrowths. The outer single layer of cells which constitutes the surface of the vesicle (fig. 147) is the ectoderm or epiblast or deric cell-layer. The little mass of hypoblast or enteric cell -mass now en larges, but remains con nected with the cicatrix of the blastopore or orifice of invagination by a stalk, the rectal peduncle (fig. 151, A, rp). The enteron itself be comes bilobed and is joined by a new invagination, that of the mouth and stomo- dyeum, ph. Fig. 151, B shows the origin of the mouth o, being a deeper view of the Same Specimen Fio. 153. Diagram of &amp;gt;ml&amp;gt;ryo of Pisidium, .1, i i in same stage as F in tig. 151 (after Lan- in the same position which kester). m, mouth ; x, anus ; /, foot ; br, is drawn in fiff. 151 A. branchial filaments ; mn, margin of the ., . . i. i mantle-skirt ; B, organ of Bojanus (ne- llie lliesoblast multiplies phridtum). The unshaded area gives its Cells, Which become the position of the shell-valve. partly muscular and partly skeleto-trophic. Centro-dor- sally now appears the embryonic shell-gland (fig. 151, C, sh). The pharynx or stomodyeum is still small, the foot not yet prominent. A later stage is seen in fig. 152, where the pharynx is widely open and the foot pro minent. No ciliated velum or pne-oral (cephalic) lobe ever develops. The shell-gland disappears, the mantle- skirt is raised as a ridge (fig. 151, E, mn), the paired shell-valves are secreted, the anus opens by a proctodteal ingrowth into the rectal peduncle, and the rudiments of the gills (br) and of the nephridia (B) appear (figs. 151, F, and 153, dorsal and lateral views of same stage), and thus the chief organs and general form of the adult are acquired. Later changes, not drawn here, consist in the growth of the shell-valves over the whole area of the mantle-flaps, and in the multiplication of the gill-fila ments and their consolidation to form gill- plates. It is important to note that the gill-filaments are formed one by one posteriorly. The labial tentacles are formed late. In the allied genus Cyclas, a byssus gland is formed in the foot and subsequently disappears, but no such gland occurs in Pisidium. The nerve-ganglia and the otocysts probably form from thickenings of the epiblast, but detailed observation on this and other points of histogenesis in the Lamellibranchia is still wanting. (3) St delle Chiaje, Memorie sulla storia e notomia degli animali senza vertebr.. del regno di Napoli, Naples, 1823-1829 ; new edit, with 172 plates, fol., 1848. (4) J. Vaughan Thompson, Zoological Researches, Cork, 1830; memoir iv., &quot;On an inhabitant of some Zoophytes.&quot; (7) C. G. Ehrenberg, Die Korallenthiere des Rothen Meeres, Berlin, 1834 (Ablutnd. d. k. Akad. d. H issenschaften in Berlin, 1832). (8) II. Milne-Edwards, Recherches anatomiques physioloyiifuts et zoolo- giques sur les I olypiers de France, Paris, 1841-1844. (9) W. H. Caldwell, &quot;On the development of Phoronis,&quot; 1 roc. Hoy. Soc., 1882. (10) Richard Owen, Memoir on the Pearly Nautilus, London, 1832. (11) T. H. Huxley, &quot;On the morphology of the cephalous Mollusca,&quot; Phil. Trans., 1853. (12) E. Ray Lankester, &quot;Con tributions to the developmental history of the Mollusca,&quot; Phil. Trans., 1875. (13) E. Ray Lankester, &quot;Notes on Embryology and Classification,&quot; Quart. Journ. Microsc. Sc., 1877. (14) J. Carriere, &quot; Das Wassergefiiss-System d. Lamelli- branchiaten u. Gastropoden,&quot; Zoolog. Anzeiger, 1881, No. 90. (15) E. Ray Lankester, &quot;Development of the Pond-Snail, &quot; Quart. Journ. Microsc. Sc., 1874, and &quot;Shell-gland of Cyclas and Planula of Linmseus,&quot; ibid., 1876. (16) R. Horst, &quot;Development of the European Oyster,&quot; Quart. Journ. Microsc. Sc., 1882, p. 341. (17) E. Ray Lankester, &quot;Coincidence of the blastopore and anus in Paludina,&quot; Quart. Journ. Microsc. Sc., 1876. (18) Id., &quot;Zoological Observations made at Naples,&quot; Annals and Mag. Nat. Hist., February, 1873. (19) W. K. Brooks, &quot; Development of the American Oyster,&quot; Report of the Commissioners of Fisheries of Maryland, 18SO. (20) Henri Milne-Edwards, Papers in the Annales des Sciences Nattirelles, 1841-18GO. (21) H. de Lacaze Duthiers, Papers in tie Annales des Sciences Natiirelles, e.g., &quot; Anomia &quot; (1854), &quot; Mytilus &quot; (1856), &quot; Dentalium &quot; (1856, 1857), &quot; Purpura &quot; (18.39), &quot; Haliotis &quot; (1850), &quot; Vermetus &quot; (I860). (22) A. Kolliker, Entwickelungsgeschichte der Cephalopoden, Zurich, 1844. (23) C. Gegenbaur, Untersuchungen iiber Ptcropoden lind Hetero- poden, Leipsic, 1855. (24) J. W. Spengel, &quot; Die Geruchsorgane und das Nerven- system der Mollusken,&quot; Zeitschr. f. wiss. Zool., 1881. (25) A. A. W. Hubrecht, &quot;On Proneomenia Shuteri nov. gen. et sp., with remarks upon the anatomy and histology of the Amphineura,&quot; Niederldndisches Archil- fur Zoologie, supple ment volume, 1881. (26) Adam Sedgwick, &quot;On certain points in the anatomy of Chiton,&quot; Proc. Roy. Soc. Land., 1881. (27) E. Ray Lankester, &quot;On some undescribed points in the anatomy of the Limpet,&quot; Annals and Mag. Nat. History, 1807; J. T. Cunningham, &quot;The Renal Organs of Patella,&quot; Quart. Journ. Microsc. Sc., 1883. (28) P. Fraisse, &quot; Ueber Molluskenangen mit embryonalem Typus,&quot; Zeitschr. f. wiss. Zool., 1881. (29) L. v. Graff, &quot; Ueber Rhodope Veranii, K611.,&quot; Morpholog. Jahrb., vol. viii. (30) H. Simroth, &quot;Das Fussnervensystem der Paludina vivipara,&quot; Zeitschr. f. iciss. Zool., 1881. (31) E. Ray Lankester, &quot;A contribution to the knowledge of Ha-moglobin,&quot; Proc. Roy. Soc. Lond., 1873. (32) H. de Lacaze Duthiers, &quot;Du systeme nerveux des Mollusques Gasteropodes Pulmones aquatiques et d un nouvelorgane d innervation,&quot; Arch, de Zoologie experimentale, vol. i. (33) C. Semper, Animal Life (for eye of Onchidium, p. 371), International Scientific series, 1881. (34) Same as number 18. (35) E. Ray Lankester, &quot; Observations on the development of the Cephalo poda, Quart. Journ. Microsc. Sc., 1875. (36) J. van der Hoeven, &quot;Bijdragc tot de outleedkundige kennis aangaaende Nautilus pompilius,&quot; Verhandl. d. K. Akad. v. Wet. Naturk., Amsterdam, 1856. (37) E. Ray Lankester and A. G. Bourne, &quot;On the existence of Spengel s olfactory organ and of paired genital ducts in the Pearly Nautilus,&quot; Quart. Journ. Microsc. Sc., 1883. (38) J. W. Vigelius, &quot;Ueber das Excretions-System der Cephalopoden,&quot; Niederldndisches Archiv fur Zoologie, bd. v., 1880. (39) Albany Hancock, &quot;On the nervous system of Ommastre.phes todarus,&quot; Annals and Mag. Nat. Hist., 1852. (40) J. D. Macdonald, &quot;On the anatomy of Nautilus iimbilicattts,&quot; Phil. Trans, oj Roy. Soc. Lond., 1S55. (41) V. Hensen, &quot; Ueber das Auge einiger Cephalopoden,&quot; Zeitschr. f. wiss. Zool., 1805. (42) A. d Orbigny, Mollustjues vivants et fossilen, t. i. (Cephalopodes acetabuliferes), Paris, 1845 (with 36 plates). (43) Bobretzky, &quot;On the development of the Cephalopoda,&quot; Trans, of Soc. of Friends of Nat. Hist, of Moscow, vol. xxiv. (Russian). (44) T. H. Huxley, &quot;Oviducts of the Smelt,&quot; Proc. Zool. Soc. Lond., 1883. (45) Same as 35. (46) F. M. Balfour, Comparative Embryology, vols. i. and ii., London, 1881-1882. (47) H. Gries- bach, &quot; Ueber das Gefiiss-System und die Wasseraufnalnne bei den Najaden und Mytiliden,&quot; Zeitschr. f. u-iss. Zool., 1883. (48) Same as 14. (49) Same as 13. (50) R. Holman Peck, &quot; The structure of the Lamellibranchiate gill,&quot; Quart. Journ. of Microsc. Sc., 1876. (51) K. Mitsukuri, &quot;Structure and significance of some aberrant forms of Lamellibranchiate gills,&quot; Quart. Journ. Microsc. Sc., 1881. (52) K. Langer, &quot; Das Gefass-System der Teichmussel,&quot; Denk. kais. Akad. d. Wissensch., Vienna, 1855-1856. (53) J. Penrose, in &quot;Report of the Committee on the Zoological Station of Naples,&quot; British Assoc. Report, 1882. (54) P. P. C. Hoek, &quot; Les orgaues de la generation de 1 huitre,&quot; Journ. de la Soc. Neerlantlaise de Zool., 1883. (E. R. L.) MOLLUSCOIDS. See BRACHIOPODA and POLYZOA. MOLOCH, or MOLECH in Hebrew, with the doubtful exception of 1 Kings xi. 7, always &quot;^BH with the article is the name or title of the divinity which the men of Judah in the last ages of the kingdom were wont to propitiate by the sacrifice of their own children. The phrase employed in speaking of these sacrifices is &quot;to make one s son or daughter pass through fire to the Moloch &quot; (2 Kings xxiii.