952 



SCIENCE 



[N. S. Vol. XXVII. No. 703 



fishes, which are but few in number, only 

 two to ten in any case as yet observed, are 

 not developed in separate sacs, but lie 

 within the lumen of the ovisac, gradually 

 compressing the ovarian stroma as they de- 

 velop. They attain a length of 20 to 25 

 millimeters before birth, while the adults 

 may be as much as 100 millimeters long. 

 Viviparity is apparently a comparatively 

 recent acquirement of these fishes, though 

 probably attained before they left the deep- 

 sea for the fresh-water cave streams. 



Notes on Diplosis sorghicola Coq.: Caele- 

 TON R. Ball, U. S. Department of Agri- 

 culture. 



The frequent failure of sorghums to 

 produce seeds in our southern states has 

 long been noted. Many theories regarding 

 the cause have been advanced : fungi, in- 

 sects and unfavorable meteorological condi- 

 tions, such as excessive precipitation, high 

 humidity. Severe drouth or hot winds are 

 the causal agencies most commonly as- 

 signed. Among the growers this trouble is 

 known as "blast" and is usually held to 

 be caused by excessive rainfall and the 

 consequent washing away of pollen during 

 the blooming period. Experiments made 

 during the past season proved conclusively 

 that the injury results from the attacks of 

 a small fly, which has been identified as 

 Diplosis sorghicola Coq., for which the 

 name sorghum midge is here proposed. 

 The eggs are laid within the spikelet and 

 the larya absorbs the juices of the ovary 

 through its body walls, causing the death 

 of the ovary and sterility of the infested 

 heads. The insect is prolific ; the life cycle 

 is short; and the crop is totally destroyed 

 in badly infested areas. Two parasites are 

 known. Relief may also be found through 

 breeding immune varieties. 



Mechanics of Orientation in Lower Organ- 

 isms: S. 0. Mast, Johns Hopkins Uni- 

 versity. 



Orientation in lower organisms stimu- 

 lated by light may be classified as direct 

 and indirect. In direct orientation the 

 organism turns directly toward or away 

 from the source of stimulation, e. g., Vol- 

 vox, Arenicola larvse, etc. 



In indirect orientation the organism 

 makes preliminary random movements, 

 which bear no definite relation to the ap- 

 parent point of stimulation, until it reaches 

 a position in which the stimulation is re- 

 duced to a minimum. This position it 

 retains in moving forward and thus be- 

 comes oriented. 



The random movements resulting in 

 orientation may be restricted to motion 

 toward a structurally defined side, as in 

 Euglena, Stentor, etc. ; or they may not be 

 thus restricted, as in some of the worms. 



A detailed study of the structure and 

 light reactions of Euglena, which orients 

 indirectly, and Volvox and Arenicola 

 larvEe which orient directly, shows that the 

 reactions of these three forms, apparently 

 so different, are fundamentally the same. 

 There does, however, not appear to be any 

 definite relation between the reactions of 

 organisms which orient by means of un- 

 restricted preliminary random movements 

 and the reactions of those in which the 

 random movements are restricted to mo- 

 tion toward a structurally defined surface. 



No theory of reaction yet formulated 

 covers all cases. The theory of Sachs, 

 formulated for light reactions in plants 

 and accepted by Loeb, who applied it to 

 animals, is not in accord with the observed 

 reactions in any of the organisms studied. 



On some Isopods of the Family DajidcB 

 from the Northivest Pacific Ocean, with 

 Descriptions of a New Species and a 

 New Genus: Haeeiet Richaedson, 

 Smithsonian Institution. 

 During the cruise of the U. S. Bureau 



of Fisheries Steamer Albatross to the 



