4. SUCCESSFUL REARING OF THE BLUE-NECKED CROWNED CRANE IN CAPTIVITY

Little has been recorded in South Africa of these remarkable birds alld the notes that follow were submitted at my request. The author is a Ranger of the Natal Parks, Game and Fish Preservation Board, and his keen observations reveal the interesting fact that a pair of Gypohierax have managed to discover a small and isolated, yet now well established grove of Raphia or Raffia Palms Raphia vinifera. It is known that elsewhere ill Africa the range of the birds coincides largely with that of the Oil Palm, and it is remarkable that so far as Zululand is concerned the species so far appears to be resident only in the two places where Raphia Palms occur; that is to say near Maputa in the extreme North and now in this artificially and quite recently introduced small grove. The name Palm-nut Vulture was first suggested by Mr. R. E. Moreau in 1943; it is considered far more suitable than the old and misleading term of Vulturine Fish Eagle, the latter apparently derived only from the bird's casual likeness 10 Haliaaetus vocifer. (J. Vincent.)     

IMMORTALITY, HUMAN NATURE, THE VALUE OF LIFE AND THE VALUE OF LIFE EXTENSION

The emerging discourse concerning the desirability of intervention in senescence to achieve radical life extension for persons has featured some striking blurring in traditional liberal and conservative commitments and positions. This affords an opportunity for re‐evaluation of these same. The canonical conservative view of the intrinsic value of life is re‐examined and found primarily to involve a denial of human prerogative, rather than an active underwriting of the value of life extension. A critique is offered of an attempted argument against aging intervention from a proto‐conservative worry about a purported threat to human nature. Immortality is found to be a red herring, but a revealing one. Further, the classic liberal view is examined and found wanting in terms of the gravity of its own commitment to, and fullness of its account of the value of life, and the value of life extension. An analysis of the liberal conception of personhood is proposed that both defines persons necessarily as processes, and demonstrates the inalienable quality of the value of life extension to persons so defined.     

夜鹭繁殖习性与生长发育研究

１９９４～１９９８年对夜鹭繁殖习性与生长发育进行了研究。夜鹭于４月中下旬迁到浙江,９月下旬、１０月初迁离,居留期１６５天。巢距地高８．５１ｍ。平均窝卵３．４９枚,孵卵期２２～２６天,育雏期３０～３５天。年繁殖力３．５０只。雏鸟体重生长模型为：Ｗｔ＝５６０１＋ｅ＾－０．２３１（ｔ－１２）（Ｒ＾２＝０．９９）;体长、体重关系式为：Ｗ＝０．０００２４６Ｌ＾２．５０２９。雏鸟体温发育分为３个时期：     

THE VOCAL REPERTOIRE OF THE GREY CROWNED CRANE BALEARICA REGULORUM GIBBERICEPS. II: THE UNISON CALL

ABSTRACT

This paper presents the acoustic features and the behavioural context of the unison call of the East African Crowned Crane Balearica regulorum gibbericeps. It speculates on the different functions of the unison call according to the situations where it is given. This is tested with the appeasement-threat hypothesis, which claims that the threatening acoustic characteristics of the unison call should be enhanced if it is given as a territorial call. In comparison, the appeasing acoustic characteristics should be stronger if the unison call is performed at flock sites where it possibly serves for mate assessment.     

MACROCYSTS IN THE LIFE CYCLE OF THE DICTYOSTELIACEAE. II. GERMINATION OF THE MACROCYSTS

Macrocyst germination was demonstrated in the five species of the Dictyosteliaceae known to produce these structures. The morphological changes that occurred during germination appeared to be identical in all of the strains examined, showing the following stages: (1) swelling of the dark, contracted content of the dormant cysts, (2) gradual loss of color and reappearance of cells within what previously appeared as a homogeneous protoplasmic mass, and (3) rupture of the heavy cellulosic cyst wall to liberate the myxamoebae. The age of the macrocyst appeared to be the most critical factor in determining whether or not germination would occur, since the cysts in many of the strains needed to age for several weeks or months before germination could be demonstrated. In Dictyostelium mucoroides strain DM-7, upon which the current study was centered, light was necessary to stimulate germination of young macrocysts—a requirement that gradually diminished as the cysts aged. The rate of germination and the temperature permitting germination were also age dependent: older macrocysts germinated more rapidly and at considerably higher temperatures than did young cysts. Although light was not essential for germination in every strain, the results obtained with strain DM-7 seem to be generally applicable to the germination process.     

THE VOCAL REPERTOIRE OF THE GREY CROWNED CRANE BALEARICA REGULORUM GIBBERICEPS. I: THE TONAL AND THE NON-HARMONIC CALLS

ABSTRACT

The study describes the vocal repertoire of the Grey Crowned Crane Balearica regulorum gibbericeps and speculates on the purpose the calls serve. The repertoire consists of 4 tonal and 7 non-harmonic calls. Chicks have 3 different vocalizations.     

MACROCYSTS IN THE LIFE CYCLE OF THE DICTYOSTELIACEAE. I. FORMATION OF THE MACROCYSTS

Macrocysts, a morphogenetic phase that is alternative to sorocarp formation in the life cycle of some cellular slime molds, are known for two genera and five species of the Dictyosteliaceae. In all of these macrocyst formation was found to be strongly affected by four factors: light, temperature, moisture, and the composition of the medium. In general, macrocyst formation was suppressed and sorocarp formation was enhanced by exposure to light, by incubation at temperatures lower than 20 C, by buffering nutrient media with phosphates, and by reducing atmospheric moisture through the use of clay covers on Petri dishes. The extent to which these environmental factors, singly or in combination, inhibited the production of macrocysts varied among the different strains and species.