The chromosome number was determined in eleven heterogonous species of gall-wasps on oaks and in four species which reproduce by constant parthenogenesis on wild roses. One of the latter group proved to be a natural triploid. Maturation was studied in representative torms from synapsis through diakinesis and the abortive first division to the second division in the laid egg. Chromosome regulation in the developing egg, the production of parthenogones of different sex and the role of the sperm are discussed briefly.
MYXOEDEMA AND PNEUMONIA BxnsOU 1065MIEDICAL JOURNAL remaining two cases all we can say is that thyroid function, perhaps already inadequate in Case 2, deteriorated acutely with the onset of infection, while in Case 3 no previous history was available but the patient became rapidly comatose with the development of pneumonia.A final point of interest was the contrast between the relative lack of symptoms and the evidence of extensive consolidation in four of our five patients. We think that the silent character of these severe infections is a matter of significance which needs stressing, and that attention should be drawn towards the possible presence of myxoedema when faced with pneumonia with minimal symptoms. SunmaryFive cases of myxoedema of acute onset, including one new case of coma, are reported. The stress factors were severe pneumonia and exposure to cold. It is suggested that in all these cases there was a sudden breakdown of function in potentially inadequate thyroid glands, already working at maximum capacity to meet normal requirements. As the pneumonia caused few symptoms in all our patients it was liable to be overlooked.We (Lennox, 1956;Davidson, 1960 rectangle-is laid over it. One or more layers of filter paper are placed on top and the coverglass is pressed down by drawing the thumb across from one end of the slide to the other. To avoid moving the coverglass on the slide the filter paper is firmly held down over one corner of the cover with the left hand while the right hand moves across from left to right. The filter paper absorbs excess stain expressed from below the coverslip. With insufficient pressure the nuclear membrane is wrinkled: with correct pressure the nuclei are evenly flattened. Extrusion of the nuclei from the cell is not disadvantageous provided that the nuclear membrane remains intact. With simple aceto-orcein they should be stored in a covered tray in a refrigerator and fresh stain added to the edge of the coverglass to prevent drying out. The hygroscopic lactic acid in lacto-aceto-orcein
SynopsisThe chromosome constitution of the bisexual beetle Ptinus clavipes Panzer (2n = 18) and of its gynogenetic form P. clavipes f. mobilis Moore (3n = 27) have been investigated. The triploid mobilis lives in close association with the bisexual species and mates freely with the males. Eggs from virgin females never pass beyond the metaphase stage and successful completion of maturation is dependent on the presence of sperm. An endomitotic split is apparent in prophase chromosomes and leads to the formation of twenty-seven pseudobivalents which undergo a pseudomeiotic division. Only one maturation division has been observed. Although the fate of the activating sperm has not been resolved it is thought that sperm nuclei give rise to isolated haploid nuclei in some eggs and interfere with normal cleavage in others. Since the triploid form may also mate with males of Ptinus pusillus Sturm and P. fur. L. with reduced numbers of progeny the affinities of the gynogenetic form is discussed. This is the only known case of gynogenesis in Coleoptera.
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