Abstract: The karyotype of finless porpoise (Neophocaena phocaenoides) has been determined in the bone marrow cells of the sternum by the colchicine-hypot-onic-fire drying technique.This is the first report of the karyotype of finless porpoise.The diploids of chromosomes amount to 44 (2 n = 44) .They may be classified into four groups and one pair of sex chromosomes.Group A consists of 5 metacentric chromosome pairs; group B has 9 sub-metacentric chromosome pairs5 group C has 2 sub-acrocentric chromosome pairs which are largest among all chromosome pairs; group D has 5 pairs of acrocentric chromosomes. The last pair of group D is smallest among the autosomes.Sex chromosomes are of X, Y type.The X chromesome is metacentric and is similar in size to the first pair of group D and the fourth pair of group B.The Y chromosome is a minute element and can be identified as acrocentric in favorable preparations.The karyotype of finless porpoise is different from those of harbour porpoise (Phocoena phocoena) and of Dall's porpoise (Phocoenoides dalli) as shown in Table 2 .

Key words: Finless porpoise, Neophocaena phocaenoides, Choromosome, Karyotype

摘要： 江豚(Neophocaena phocaenoides)是鲸目(Cetacea)鼠海豚科(Phocaenidae)的一种小型齿鲸,在淡水和海洋中均有分布。关于江豚染色体的研究,国外文献中尚未见记载,国内亦无报道。Pilleri和Gihr(1972,1975)根据江豚的形态解剖学的研究,认为我国产的江豚和印度洋的及日本海的江豚不属同一个种,但国际上对此尚有不同意见。因此,搞清江豚染色体的核型,将可有助于澄清江豚属的的分类问题。本文就我国长江产江豚的染色体核型作初步探讨。

关键词: 江豚, 染色体, 核型