Abstract: The finless porpoise,Neophocaena phocaenoides is distributed in the form of a narrow band along the coast line of tropical and temperate Asia and in the Yangtze river．
The differences of external measurements among the populations in Chinese waters were studied using t-test．analysis of covariance and discriminant analysis．Based on 226 specimens collected between 1974 and 1993 by the Cetacean Research Laboratory．Nanjing Normal University．A total of 84 from Yangtze population．97 from Yellow Sea population and 45 from South China Sea population was available for study．
According to the distinct differences in external measurements，sktull measurements(Gao,1991)，growth and reproduction pattern (Gao et al.1993) among the Yangtze
River,Yellow Sea and South China Sea populations as well as the differences among the Chinese populations and the South Asian and Japanese populations，the authors suggest that Neophocaena phocaenoides be consisted of 3 subspecies:1) N eophocaena phocaenoides phaenoides(Cuvier,1829)，inhabits the coastal waters of South China Sea and southern part of East China Sea.Diagnosis:Dorsal ridge originates after the m idlength on dorsum,10-14 rows,of tubercles，tubercle area is 48-120 mm or larger in width.2)N .P．sunameri Pilleri and Gihr,1975．inhabits the coastal waters of Yellow Sea，Bohai Sea,East China Sea and off the west coast of Korea．Diagnosis：Dorsal ridge originates before or at midlength on dorsum ,16 mm or more in height，and reaches 55mm in maximum ，2-9 rows of tubercles，may exceed 9 rows in Japanese porpoise．Tubercle area l2mm or less in width，may exceed l2 mm a bit in Japanese porpoise．3)N .P asiaeorientalis(Pilleri and Gihr，l972)，inhabits the middle and lower reaches of the Yangtze River,the Dongting Lake and the Boyang Lake Diagnosis:Dorsal ridge originates before or at midlength on dorsum ,2-5 rows of tubercles，tubercle area 8 mm or less in width.Dorsal ridge hardly exceeds 15 mm in height．This is the only subspecies inhabiting freshwater．Statistical analysis also demonstrates that：among the three populations in the Chinese waters,individuals from the Yellow Sea population have the longest snout，while those from the Soutti China Sea have the shortest；Individuals from the Yangtze population have the thickest blubber，while those from the South China Se a have the thinnest；The girth of the individuals from the Yangtze population is relatively larger than that from the other two populations.The barrier between N.p.phocaenoides and N ．P．sunameri may be attributed mainly to the water temperature in different areas.That between N .P.asiaeorienalis and the coastal population may be mainly attributed to the salinity of the river and sea waters．

Key words: Finless porpoise, External measurements, Geographical variation, supspecies, distribution

摘要： 1974年至1993年间在中国长江和大陆沿岸海域采集各年龄段的江豚标本226号：长江种群标本84号，黄海种群标本97号，南海种群标本45号。选用了35项外形测量指标，用t-检验、协方差分析和多元分析研究了各种群之间在外形上的差异。结果表明，黄海种群的吻长相对最长，南海种群的哟长相对最短。长江种群的体围比较大，体脂最厚。黄海和南海种群的体围较小，南海种群的体脂最薄。限裂高、眼裂长和鳍肢宽在南海种群中相对最大。在种群之间差异最大，可作为分类鉴别特征的指标是疣粒区宽、疣粒列数和背嵴高。将南海种群与其它两个种群分开的判别函数1主要与疣粒区宽和疣粒列效相关，而把长江种群与黄海种群分开的函数2主要与背嵴高相关。通过与日本和南亚种群的比较，作者认为江豚包括以下三十亚种：1)江豚指名亚种，Neophocaena phocaenoides phocaenoides(Cuvier，1829)：背嵴始于体背后部，体背部疣粒区宽48-120mm，疣粒l0-14列，分布稀疏。2)江豚北方亚种，Neophacaena phacaenoides sunameri(Pilleriand Gihr,1975：)背嵴始自体长之半或其前，背嵴高通常在16mm 以上。疣粒区宽3-l2mm，疣粒1-9列，排列紧密。日本江豚的可达10列左右，可能稍宽一些。3)江脉长江亚种 Neophocaena phocaenoldes asiaeorientalis(Pilleri and Gihr，1972)：背嵴始自体长之半或其前,背嵴高通常不超过15mm。疣粒区宽2一8mm，疣粒2—5列。北方亚种与指名亚种之间的屏障可能主要是不同海域的海水温度，而长江亚种与海生亚种之间的屏障可能主要是江水与海水中的盐度，以及由此造成的其它环境因子的差异。

关键词: 江豚, 外形, 地理变异, 亚种, 分布