A STUDY ON PATTERNS OF PLACOII7 SCALES OF SHARIKS

The present paper deals with the zuarphologv of the placoid scales of sharks with particular reference to their patterns. 189 species belong to 62 genera, 21 (amities and 9 orders have been iwestited, of which 80 species~based on Chinese specimens and ID9 species are cfuoted from foreign materials. According to their special characte-. ristics of this paper consists of three parts: 1, the patterns of placoid scales of sharks;the morphological characteristics of placoid scales of sharks in different tags of classification;3. discussion and conclusion,