Mantle robust, slightly flattened dorsoventrally. It can be broad or slender; oval, oblong or nearly circular in outline. The anterior of dorsal mantle margin projected forward, not fused with head. Fins narrow which located dorsolaterally on mantle, approximately equal to mantle length; posterior fin lobes free, not connected to each other. Head is robust and slightly narrower than mantle. Eyes are prominent, which covered by a transparent membrane and a conspicuous secondary fold on the eyelid. Mouth surrounded by 10 appendages (8 arms and 2 tentacles). The cuttlefish arms consist of 2 to 4 suckers in transverse rows. Tentacular clubs consists of four or more suckers in transverse rows and tentacles retractile into pockets on the ventrolateral sides of the head between arms III and IV. Internal calcareous cuttlebone was located dorsally in the mantle which underneath the skin and cuttlebone length usually equal to the mantle length. The cuttlebone shape are ranges from lanceolate to oval or diamond-shaped whereas dorsal side is calcareous plate and ventral side finely laminate. Buccal membrane present, with or without suckers; each radula tooth unicuspid (with a single projection).
Genus: Sepia Linnaeus, 1758
Species: Sepia prashadi Winckworth, 1936
Arm suckers are tetraserial. Hectocotylus present on left ventral arm with 4 rows of normal size suckers proximally, 12 to 14 rows of suckers medially and normal size suckers to arm tip. Suckers of hectocotylus in 2 ventral series are displaced laterally, with gap between on proximal part of modified region, becoming closer together distally. Tentacular club is short, oval and sucker-bearing surface is flattened, with 3 to 5 suckers in transverse rows. Suckers differ markedly in size with 4 median suckers extremely large, surrounded by moderately large suckers. Swimming keel of club extends slightly beyond carpus. Dorsal and ventral protective membranes not joined at base of club. Cuttlebone outlines oblong, bone triangular, obtuse anteriorly and bluntly rounded posteriorly. Chitin borders lateral and anterior margins of cuttlebone. Spine long, pointed, straight, directed dorsally, with dorsal and ventral keel. Striated zone convex and separated from outer cone by narrow, smooth marginal zones; sulcus shallow, narrow, flanked by rounded ribs, extends entire length of cuttlebone. Anterior striae is shallow with m-shape. Inner cone limbs are narrow anteriorly, broaden posteriorly and raised into rounded with thickened ledge. Outer cone is chitinous laterally and calcareous in expanded posterior part. Dorsal mantle has transverse zebra stripe pattern in breeding males.
Sepia prashadi Winckworth, 1936- [Jereb and Roper (2005): 111-112]
Sepia prashadi has been assessed as Least Concern in the IUCN Red List as although it is fished commercially in some localities, it has an extremely wide distribution and the species as a whole is therefore likely robust to locally intense activity.