4 o2 SCIENCE PROGRESS 



democratica, a. typical plankton organism, controls to a significant 

 extent its own distribution, just as certainly as does any fish 

 or other animal commonly included under the term nekton." 

 Goodrich set out to investigate the question of the segmentation 

 of the head of Scylliutn in the light of our present knowledge 

 of other forms, and has set forth his results in a paper entitled 

 " On the Development of the Segments of the Head in Scylliutn " 

 {Quart. Jour. Micro. Sci. vol. lxiii, April 191 8). Three pro-otic 

 segments were identified corresponding to the profundus, tri- 

 geminal, and facial nerves, and whose muscles are supplied by 

 the oculomotor, trochlear, and abducens nerves. The post-otic 

 region of the head comprises 4 somites, i.e. 4-7, of which 4 is 

 related to the glossopharyngeal and 5, 6, and 7 to the first 

 three branchial branches of the vagus, " The eighth somite 

 belongs to the first spinal nerve, of which the dorsal root is 

 absent or vestigeal in later stages, and to the vagus. The third 

 and fourth segments, and perhaps also the first and second, 

 contribute to the mesenchymatous sheet below the hind brain 

 in which the parachordal cartilages develop." 



Other papers include : Kendall, " The Rangely Lakes, Maine, 

 with Special Reference to the Habits of the Fishes, Fish Culture, 

 and Angling" {Bull. Bureau Fish. Washington, May 191 8) ; 

 Crozier, " Tactile Reactions of the De-eyed Hamlet " {Jour. 

 Comp. Neur. vol. xxix. April 191 8) ; Johnson, " The Peripheral 

 Terminations of the Nervus Lateralis in Squalus sucklii " {ibid. 

 June 191 8) ; Norris, " The Morphogenesis of the Thyroid 

 Gland in Squalus acanthias " {Jour. Morph. vol. xxxi. June 

 1918) ; Gilchrist, " Notes on Eggs and Embryos of the South 

 African Myxinoid, Bdellostoma {Heptatretus) hexatrema, Mull | 

 {Quart. Jour. Micro. Sci. vol. lxiii. April 191 8) ; Lambe, " On 

 the Remains of a Selachian from the Edmonton Cretaceous of 

 Alberta " {Ott. Nat. May 191 8) ; Detwiler, " Experiments on 

 the Development of the Shoulder-Girdle and the Anterior Limb 

 of Ambly stoma punctatum " {Jour. Exp. Zool. vol. xxv. April 

 191 8) ; Harrison, " Experiments on the Development of the 

 Fore-limb of Amblystoma, a Self-differentiating Equipotential 

 System " {ibid.) ; Johnson, " On the Question of Commissural 

 Neurones in the Sympathetic Ganglia " {Jour. Comp. Neur. 

 vol. xxix. June 191 8) ; Hooker, " The Effect of Reversal of a 

 Portion of the Spinal Cord at the Stage of Closed Neural Folds 

 on the Healing of Cord Wounds, on the Polarity of the Elements 



