Indian Journal of Marine Sciences Vol. 31(2), June 2002, pp. 150-152 Short Communication Intercapsular embryonic development of the big fin squid Sepioteuthis lessoniana (Loliginidae) V. Deepak Samuel & Jamila Patterson* Suganthi Devadason Marine Research Institute, 44, Beach Road, Tuticorin – 628 001, Tamil Nadu, India ( E.mail :
[email protected] ) Received 18 June 2001, revised 22 January 2002 The egg masses of big fin squid, Sepioteuthis lessoniana were collected from the wild and their intercapsular embryonic development was studied. The average incubation period of the egg varied between 18-20 days. The cleavage started on the first day and the mantle developed between third and fifth day. The yolk started decreasing eighth day onwards. The tentacles with the sucker primordia on the tip were prominent from tenth day. The yolk totally reduced between thirteenth and seventeenth day and the paralarvae hatched out on eighteenth day.The developmental stages of the embryo inside the capsules during the incubation period is understood. [ Key words: Sepioteuthis lessoniana , intercapsular development ] There are about 660 species of cephalopods in the the death of the embryo. Egg capsules were taken world oceans, of which less than hundred species are everyday to study the developmental stages of the of commercial importance. In the Indian seas, about growing embryos. Size of the egg capsules, eggs and 80 species of cephalopods exist but the main fishery is the embryos inside the eggs were recorded everyday contributed by only a dozen or so. Though they play till hatching. Various stages of development were ob- an important role in the economy of our country, their served and recorded as line drawings and photographs early life cycle and reproductive biology are not yet with the help of a light microscope.