Febbuakt 4, 1916] 



SCIENCE 



183 



The pendulum of thought never retraces its 

 course; but there is regularly a net gain. 



The extreme position, or furthest point of each 

 swing, is almost invariably wrong. 



Each leader contributes something real to prog- 

 ress, and it is unwise to utterly discredit Mm. 

 Witness Morgan and pangenesis. 



The return from the extreme of the Mendelian 

 swing. Witness Castle and E. B. Wilson. 



The position of the systematist under present 

 conditions. 



A Case of Sex-Linked Inheritance in Man: Hans- 

 ford MacCdrdy, Alma College. 

 In the history of a certain family in Michigan, 

 there occurs a most interesting case of the trans- 

 mission of a peculiar character, which manifests 

 itself at the approach of maturity in a certain 

 proportion of the males. It makes its appearance 

 only after a long series of complex physiological 

 processes and in a remote period of development. 

 The factors are evidently not simple, and pos- 

 sibly may manifest themselves in various ways; 

 but the particular character here noted affects the 

 feet of males in a definite proportion. 



An affected male does not transmit the factor 

 or factors to his sons. He transmits them through 

 his daughter married to a normal male through 

 four out of five of his granddaughters, and through 

 these to half of their sons. 



According to the chromosomal hypothesis of con- 

 trol of development and heredity this is a case of 

 sex-linked inheritance and is limited to one half 

 of the sons of the daughters of affected males. It 

 also indirectly points to the transmission of char- 

 acters or factors detrimental to one sex. 



The Components of the Cereiral Ganglia and 

 Nerves of a 23 mm. Embryo of Squalus Acan- 

 thias: F. L. Landacre, Ohio State University. 

 The 23 mm. embryo of Squdllus was selected be- 

 cause it is sufficiently developed to enable one to 

 recognize the principal nerves and determine their 

 composition while the ganglia are still fairly well 

 separated so that their boundaries can be deter- 

 mined. The chief ganglia and nerves are found to 

 be typical for Ichthyopsida in general. Some of 

 the peculiarities noted are the very small size of 

 oph. sup. v.; the separateness of the lateral lines 

 organ primordia; the large size of the epibrachial 

 placodes; the precocious character of the lateral 

 line nerves as compared with other nerves. The 

 analysis, which can be shown briefiy only by 

 means of a diagram, is offered tentatively in the 

 absence of a published analysis of a more mature 

 individnal. 



Silk Spinning in Its Relation to the Feeding Hab- 

 its of Chironomus lobiferus Say: Adelbert L. 

 Leathers, Cornell University. 

 The larvffi of Chironomus lobiferus were found 

 inhabiting the air cavities of the living stems of 

 Sparganium sp., which they penetrate by boring 

 two small openings through the epidermis. Here 

 they maintain suitable living conditions by a regu- 

 lar undulating motion of the body which sets up a 

 current of water through the burrow. An exami- 

 nation of the stomach contents showed the food to 

 be plankton and not the tissue of the plant. If 

 was found that these larvae wUl adapt themselves 

 to living in glass tubes, and under such conditions 

 careful observation revealed a conical net fastened 

 at the base to the silken lining of the larval gal- 

 lery and held extended by radiating threads at- 

 tached to its apex. This net is made to bulge out 

 by the pressure of the current forced into it. The 

 smaller particles become tangled in its meshes and 

 the protozoa, diatoms and other unicellular algae 

 are largely removed, although some escape through 

 gaps near the rim of the net. When this current 

 has been maintained for about ten minutes, re- 

 gardless of the amount of food in the net at any 

 time, the larva turns about in its burrow and 

 grasps one edge of the net and forces it into its 

 mouth, then rotates its body and grasps another 

 part, and so on until the net is entirely swallowed. 

 Then it spins another, spreading and attaching the 

 silk by its anterior prolegs ; turns about and be- 

 gins the undulating motion again. 

 The Sesistance of Starved and Normal Fishes to 

 Low Oxygen an4 the Effect upon this Sesist- 

 ance of Acids, Alkalies, Salts, Etc.: Morris M. 

 Wells, University of Chicago. 

 The resistance of normal fishes to various con- 

 centrations and combinations of oxygen and car- 

 bon dioxide was determined in 1913 (Biol. Bull., 

 Vol. 25) and since that time an improved appa- 

 ratus has been devised and the resistance of 

 starved fishes at different periods during the starv- 

 ing process has been determined. The work is 

 being pushed further in an attempt to determine 

 the relation of the oxidations of the fishes to the 

 presence of other substances in the water. The 

 effects of acidity and alkalinity have been com- 

 pared, the dying time in running and stagnant 

 water has been determined and the work that is 

 now under way contemplates the determining In 

 the next three weeks of the effect upon the resist- 

 ance of the fishes of the presence of various salts 

 and sugars, and a comparison of the effects of 

 KCN as compared with low oxygen. 

 Results already obtained: 



