Febki-ary 12. 1904.] 



SCIENCE. 



247 



(3) Some experiments were made to de- 

 termine the eifeets of different kinds of 

 metal piping on fishes and other forms of 

 life in aquaria. (4) Some experiments 

 with phosphorescent bacteria obtained 

 from sea water, to determine the part 

 played by them in the production of phos- 

 phorescence in various Crustacea. 



John Y. Graham, Ph.D., professor of 

 biology. University of Alabama: 'A Study 

 of a Parasite of the Oyster (Bucephalus 

 cuculus McC.).' This trematode, though 

 very common in the region of Beaufort, 

 N. C, and doubtless elsewhere on the 

 southern coast, was not found in any of 

 the oysters of the region near Woods Hole, 

 although large numbers of the latter were 

 examined, coming from Wareham River 

 and Buzzards Bay. Dr. Graham was con- 

 sequently obliged to confine his attention 

 to the material which he had collected two 

 years before at Beaufort. From a study 

 of this, a careful account is now possible 

 of the structure of the most advanced 

 cercaria stages, which will perhaps give us 

 a clue to the identity of the adult form, 

 the latter being without doubt some species 

 of the genus Gasterostomum. 



Clarence W. Halm, A.M., graduate stu- 

 'dent. Harvard University: (1) 'On Dimor- 

 phism in Metridmm marginatum.' Re- 

 generation experiments begun the year 

 before and continued during the past 

 summer led to the conclusion that the 

 diglyphic Metridia are typical, and that 

 the monoglyphic individuals arise by 

 asexual budding from the base of the body 

 or column. This method of reproduction 

 is very common. The diglyphic condition 

 is not transmitted asexually. The method 

 of regeneration was also worked out. A 

 new pair of directives is usually produced 

 on the regenerated side of the young 

 polyp. (2) 'On the Blood Parasites of the 



Turtle.' As a result of studies begun at 

 Harvard and continued at Woods Hole, 

 Mr. Halm believes that he has established 

 the existence of three kinds of adult indi- 

 viduals, with distinct life cycles similar to 

 those described by Huitzi ('02) for 

 Drepanidium ranarum, of the frog. There 

 was found to be an asexual form, which 

 reproduced by a process of sporulation dif- 

 ferent from that of the sexual individual. 

 In the sporulation of the latter, a process 

 of mitosis was found to occur. The adult 

 sexual hasmogregarine, which is worm-like 

 in form, is believed by Mr. Hahn to be 

 identical with the vermiform parasite de- 

 scribed by Siegel ( '03 ) in the leech, 

 Placobdella catenigera. 



Arthur D. Howard, M.S., graduate stu- 

 dent, Harvard University: 'Minute Struc- 

 ture of the Rods of the Retina of Fishes.' 

 Mr. Howard continued studies, previously 

 made upon higher vertebrates, now using 

 various fishes. Retinae of the following 

 forms, among others, were examined with 

 the polarizing microscope, and confirma- 

 tion of previous results obtained; butter- 

 fish, squeteague, sand-dab, king-fish, men- 

 haden, barracuda, eel, tautog, bonita, 

 cutlass-fish, smooth dog-fish and skate. 



Lynds Jones, M.S., instructor in zoology, 

 Oberlin College: 'The Food of Marine 

 Birds.' The investigations were made on 

 AVeepecket, Penikese and Muskeget Islands. 

 Stomachs of yoiing terns were examined, 

 and the feeding of the young by the parent, 

 as well as the feeding of the adult birds, 

 were carefully examined. Mr. Jones gives 

 the following estimate of the tern popula- 

 tion of the various islands where they 

 nest: Weepecket, 2,000; Penikese, 10,000; 

 Muskeget, 80,000; total, 92,000 terns. The 

 two species (Steriia hirundo and 8. dou- 

 galli) are represented in about the pro- 

 portion of two to one. The feeding habits 

 and food of the two are the same. The 



