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 Scyliorhinus canicula (L.) caught near Roscoff (France) and reared at recorded temperatures as they developed from first cleavage to hatching, the first reasonably complete developmental table was worked out for this classical material in vertebrate embryology. The successive stages, described and numbered from 1 to 34, correct and replace the incomplete stages A-Q proposed by Balfour (J. Anat. Physiol., 10:555-576, 1876) and other even less complete series later published, and is unique in the inclusion of a timetable at 16 degrees C. The stages can be identified, usually through the cleared eggshell wall, with naked eye or low magnification. This table of normal stages of Scyliorhinus can be adapted with slight modification to other chondrichthyan fishes. (C) 1993 Wiley-Liss, Inc.