602 



SCIENCE. 



[N. S. Vol. IV. No. 9 



read by D. S. Kellicott giving tlie results of 

 observations on the variations in size, ap- 

 pendages and coloration of Enallagma 

 carunculatum Morse, Gomphiis fraternus Say, 

 and G. externus Selys. It was shown that 

 the size of these odonates is remarkably con- 

 stant in Ohio. That the male abdomi- 

 nal appendages are almost without varia- 

 tion, affording the most reliable generic and 

 specific characters; and that many color 

 markings commonly used in description are 

 too inconstant to be relied upon independ- 

 ent of structural characters. 



5. 'A Case of Excessive Parasitism' was 

 then briefly described by L. O. Howard. 

 He described in some detail the facts con- 

 cerning the rearing of one hundred and 

 twenty-seven specimens of six species and 

 five genera of Chalcididse from the Leca- 

 nium scales on a twig of arbor vitse received 

 from Ottawa, Canada. 



6. * Notes on the Occurrence of Dragon- 

 flies in Ohio in 1896' was a second paper 

 by D. S. Kellicott which stated that Odonata 

 have been unusually abundant in Ohio the 

 present season, which was unexpected, in- 

 asmuch as the seasons of 1894 and 1895 

 were those of extreme drouth, causing the 

 water to wholly disappear from ponds and 

 streams over wide areas. It would appear 

 to be a fair inference that the nymphs can 

 sustain themselves in the mud or in cavi- 

 ties of the dry earth during periods of pro- 

 longed drouth. Many species appeared 

 weeks, and in some cases months, before the 

 usual date. This was thought to be due to 

 continuous hot weather, beginning April 

 10th. At Columbus ten species were taken 

 in April. 



7. ' Scyllarus and Anemonia — A case of 

 Semi-commensalism,' by Edward L. Rice, 

 referred to a specimen of Scyllarus, con- 

 fined in the same aquarium with Anemonia, 

 was observed to lie habitually in the vicin- 

 ity of the anemone, returning to the same 

 when placed in a distant part of the tank 



among stones or algse, furnishing ideal 

 nooks for concealment. This case is of in- 

 terest, in connection with the well-known 

 extreme symbiosis of Pagurus and Adamsia, 

 as showing that the Crustacean seeks the 

 anemone, probably gaining protection from 

 the nematocysts of the latter. 



8. This ended the papers and discussions 

 of the first day. The second, "Wednesday, 

 was begun promptly with a fair attendance; 

 the first paper was by Prof. C. W. Hargitt, 

 entitled ' Notes upon Cordylophora.' Cor- 

 dylojihora has long been known to be capa- 

 ble of existence under a wide range of con- 

 ditions. In December, 1895, a colony of 

 these hydroids, growing on a bit of slag in 

 company with several specimens of acorn 

 barnacles were brought to the writer in a 

 pint of brackish water. They remained in 

 a jar in the laboratory for several weeks and 

 were twice frozen almost solid ; they were 

 then supposed to be dead and were set 

 aside. After some time the water was 

 partly poured off and replaced from the top 

 and once more set aside when the barnacles 

 were seen to be alive ; then specimens of 

 Cypris were put in the jar for food. Late 

 in May there were no signs of life; the 

 water was again poured ofi" and replaced 

 from the top. After several weeks it was 

 noticed that there were several colonies of 

 the hydroids feeding freely. The barnacles 

 also were alive. Both forms had withstood 

 freezing and confinement in a limited quan- 

 tity of water which had been gradually 

 changed from sea water to fresh water. The 

 hydroids were still alive August 20th. 



9. The first of the morphological papers 

 was read by Mrs. Susanna P. Gage, on 

 ' Modification of the Brain during Growth.' 

 A brief abstract follows : 



1. The greater bends of the brain tube 

 are associated with early development of 

 the eye and its nerve fibers, the post-com- 

 missure, the ventral commissure and the 

 fifth nerve. 



