A SERIES OF NORMAL STAGES FOR DEVELOPMENT OF SCYLIORHINUS-CANICULA, THE LESSER SPOTTED DOGFISH (CHONDRICHTHYES, SCYLIORHINIDAE)

By observing numerous living eggs from the lesser spotted dogfish Scyl iorhinus canicula (L.) caught near Roscoff (France) and reared at reco rded temperatures as they developed from first cleavage to hatching, t he first reasonably complete developmental table was worked out for th is classical material in vertebrate embryology. The successive stages, described and numbered from 1 to 34, correct and replace the incomple te stages A-Q proposed by Balfour (J. Anat. Physiol., 10:555-576, 1876 ) and other even less complete series later published, and is unique i n the inclusion of a timetable at 16 degrees C. The stages can be iden tified, usually through the cleared eggshell wall, with naked eye or l ow magnification. This table of normal stages of Scyliorhinus can be a dapted with slight modification to other chondrichthyan fishes. (C) 19 93 Wiley-Liss, Inc.