PAGE 



CONTENTS. 



Tbansaotions of the Society — 



VIII.— On the Estimation of Apertuee in the Microscope. By 



the late Charles Hockin, jun. (Plate VII.) .. .... ..337 



IX, — Note on the Proper Definition of the Amplifying Power 

 OF A Lens or Lens-system. By Prof. E. Abbe, Hon. 



F.K.M.S. (Fig. 48) .. .. .. .. ., .. 348 



X.— On Certain Filaments observed in Surirella bifrons. By 



John Badcockj F.R.M.S. (Figs. 49 and 50) .. 352 



Summary of Current Researches relating to Zoology and 

 Botany (principally Invertebrata and Cryptogamia), Mioeo- 

 sooPY, &c., including Original Communications from Fellows 



and OTHERS .. .. .. 354 



Zoology. 



Contributions to the History of the Constitution of the Ovum 354 



Origin of Metameric Segmentation .. .. 355 



Gctstrma Theory .. .. 357 



Changes of the Generative Products before Cleavage .. .. 357 



Development of Spermatozoa .. .. .. .. .. .. .. 359 



Human Embryo ., .. .. 359 



Placentoid Organ in the Embryo of Birds .. ., .. 360 



Development cf the Spinal Nerves of Tritons . . 360 



Poison of Batrachians ... . . . . . . . . 360 



Development of Lacerta agilis 361 



Development of Teleostei .. .. .. .. .. .. .. .. 362 



Influence of High Pressures on Living Organisms . . 362 



Intracellular Digestion of Invertebrates .. .. .. .. 363 



Gustatory Bulbs of Molluscs .. .. .. .. 865 



Morphology of the Menal Organs and Coelom of Cephalopoda 365 



Procalistes : a young Cephalopod with Pedunculate Eyes .. .. .. .. 367 



Gill in some Forms of Prosobranchiate Mollusca , , , . . 367 



Kidney of Aplysia . . . . . . 367 



Visual Organs of Lamellibranchs .. 368 



Development of Salpa.. i. .. .. 368 



Budding of Anchinia 369 



Morphology of Flustra menibranaceo-truncata 371 



Corsebus bifaseiatus .. .. 372 



Mouth-Parts of Diptera .. 372 



Moufh-Organs of Lepidoptera .. .. •• 372 



Malpighian Vessels of Lepidoptera .. .. 373 



Abdominal Muscles of the Bee .. .. .. .. .. 373 



Flight of Insects .. .. .. .. .. 374 



Aphides of the Mm .. .. 374 



Head of Scolopendra.. 374 



Skeletotrophic Tissues and Coxal Glands of Limulus, Scorpio, and 



Mygale .. .. .. .. .. .. .. 375 



Liver of Decapods .. .. 375 



' Cliallenger ' Copepoda . . 376 



Longipedina Paguri .. .. .. .. .. .. .. .. .. 377 



Cytheridss .. .. .. .. .. , .. .• 377 



Deep Sea Crustacea .. 377 



Development of Worm Larvm 378 



Excretory Apparatus of Hirudinea .. ., 379 



Function of Pigment of Hirudinea . . . . 379 



Otocysts of Arenicola grubii .. .. .. 380 



Manayunkia speoiosa .. .... .. 380 



Life-History of Thalassema ,. 381 



