covered with scaleswhich is not at all surprising when we consider that it was not until the eighteenth century that dolphins were first distinguished from fishes, and this despite the fact that Aristotle, the father of biology and medicine, had pointed out as early as 400 b.c. that dolphins have warm blood and lungs, that they are viviparous, and that they suckle their young just as lun-ses, dogs and human beings do. Aristotle also mentioned the 'Mysticetus\ an animal which had 'pig's bristles' for teeth. This was most probably his way of describing the hairy fringe at the inner side of the baleen of the whalebone whales. He also knew the Sperm Whale, which he called Phalaena, and he listed the most important characteristics of porpoises and dolphins.second half of the eighteenth century the great anatomist Petrus Camper also did a great deal of work on stranded whales, van Breda supervised the dissection of a Bottlenose Whale stranded off Zandvoort on the 24th July, 1846, and Vrolik, the founder of the anatomical collection of the University of Amsterdam, investigated a great many Cetacean organs.In Belgium, van Beneden was responsible for the splendid collection of skeletons, which form so important a part of the
Contents 5 REMARKS ON THE DISTRIBUTION AND MIGRATION OF WHALES with regard to the determination of the species than those of other observers. His data have been collected in a special table (table 5). Grateful acknowledgment is also made to Dr. S. G. BROWN (N.I.O.-Wormley-England) who was extremely helpful in reading the manuscript and suggesting a number of corrections based on a very thorough knowledge of the subject. 2. DETERMINATION OF SPECIES In the instructions given to our collaborators on board of the ships, it was asked to record sightings of all big whales, i.e. all Baleen Whales and the Sperm Whale. In the forms date, hour, position of the ship, visibility, wind and other factors influencing the reliability of the observations could be filled in, as well as the number of animals, the presence or absence of calves and the presumptive species. It was asked to record as many characteristics as possible that could be of some use to the determinationof the species, as for example the estimated length, colour, height and shape of the blast, absence or presence of the dorsal fin, visibility of flukes and flippers etc. It was also asked to record some particulars about respiration, speed of swimming and behaviour of the animals. These particulars were used by collaborators of the Whale Research Group in determining the species of the animals involved. It turned out that this was possible with a high degree of reliability in Right Whales (Eubalaena glacialis Bonnat.; Eubalaena australis Desm.), Humpback Whales (Megaptera novaeangliae (Borowski)) and Sperm Whales (Physeter macrocephalus L.). There was such a small number of sightings of Right Whales, Grey Whales and Little Piked Whales, that by charting the records on monthly maps, it was not possible to draw the same sort of conclusion about their distribution or migration as with regard to the other species. They are dealt with in separate chapters. It was quite evident that unexperienced observers would not be able to distinguish with any reliability between Blue Whales (Balaenoptera musculus (L.)), Fin Whales (Balaenoptera physalus (L)), Sei Whales (Balaenoptera borealis (Lesson)) and Bryde Whales (Balaenoptera brydei (Olsen)). Just as it was done by BROWN (1957, 1958) we collected the sightings of these four species under one single heading: rorquals. And just as BROWN, we distinguished also a category "whales" for all those cases in which it was not even possible to distinguish 8 E. J. SLIJPER, W. L. VAN UTRECHT AND C. NAAKTGEBOREN says that in April Blue Whales are observed at the Faroes coming from the Southwest on their northward run. It is also in accordance with the statements that Blue Whales migrate northward along the west coast of Ireland and the Hebrides in May and June (KELLOGG, 1929) and that Fin Whales pass these coasts in a north east direction in May (HINTON, 1925). From the charts it is quite evident that there are large concentrations of rorquals in some special regions of the Atlantic Ocean, especially in certain coastal waters. These are...
Combining the differences in collecting area and susceptibility, the flying locusts are thus about 2 •4 times as vulnerable to sprays of 4 : 6-dinitro-ocresol solution as are settled ones and about twice as vulnerable to diazinon. The difference is further enhanced when the application of these results to a particular spraying operation is considered, owing to the wind gradient near the ground which effectively reduces the path-length of the settled locusts through the spray and may also reduce their normal equivalent areas. In actual field operations with aircraft, this increased vulnerability is, at times, more than counterbalanced by the low densities of flying swarms with consequent very low kills per gallon of insecticide.
ment.retardée pâr râpport aux animaux terrestres. ces faits rotrt en rapport avec la t-ension en oxygène-du sâng.-L,élévation de celle_ci ap"ès ia orir.ao"e entraine I'occlusion du canal ; une ãéficience en oxygèn" "ri àî "ã"^i"J"" "ap^_ ble de ìtouvrir à nouveau. L'auteur examine la bio"rogie a", ",,i-u"" marins en fonction de ces diverses données et compare notamrnent les cétacés et re Phoque veau-marin aux a-utres pinnipèdes, dont res ¡"""", ,r"-p¿rr¿t""nt dans I'eau qu'âgés de 3-4 semaines au moins et parfois plüs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.