Authors: Jakov Prkic & Ian F. Smith, Nov. 2012. Updated March 2013.
Account based on Bergh’s original description of specimens from Trieste; Schmekel & Portmann (1982); and detailed study by J.P. of over 100 specimens in Croatia at sites 130-300km from Trieste. Atlantic finds differ in some respects from this description [image33]; they may be a distinct Atlantic form or another species . Investigation is required.
Body (excluding appendages)
Mature adults usually 6mm – 12mm long, 17mm maximum. Individual length varies with extension; 13mm specimen can become 15mm at extreme extension [image1]. Reports of 20mm - 25mm may be errors of estimation, identification or confusion, e.g. same image shown as 25mm on Sea Slug Forum and 15mm on Opisthobranchs of the Mediterranean Sea .
Body varies from depressed, very broad, ellipse to high, narrow, attenuated ellipse with almost parallel sides . Mantle usually a dull or dark shade of brown, green or yellow , but occasionally bright yellow, bright orange-yellow , black-grey  or blue-grey  are locally common. Usually dorsum darkest at centre, but occasionally darker dorso-lateral bands . Often, mantle has fine black-brown specks .
Mantle covered by well-spaced spiculose tubercles, variable in number and size; shape ranges from low rounded  to conical with obtuse tip , but always widest at base. Often, some tubercles inflated, proportion varies from none  to almost all . Those with many inflated tubercles (rare) could be confused with small D. verrucosa. Tubercles usually darker than mantle; often with fine black apical spot giving mantle an ocellated appearance . Proportion of tubercles with dark apices varies from very few  to almost all . Tubercles lacking dark pigment may be concolorous with mantle. Detritus often adheres to tubercles.
Up to twenty short, irregularly arranged, spicules in large tubercles . Seen under magnification in good light, some spicules may protrude from tubercles ; protrusion varies with condition of specimen. A few tubercle-spicules may be much longer than others. Long spicules in mantle radiate from base of tubercles and meet others, often giving quilted appearance to mantle . Spicules usually visible in translucent underside of mantle .
Lamellae translucent pure white  to yellowish white , distinctly different from mantle colour, markedly contrasting with frequent dull mantles. Two large spatulate guard-tubercles on rim of rhinophore pit . Guard-tubercles have smooth inner face, and curved outer face, often with projecting spicules . Rim often raised into collar of tissue connecting guard-tubercles, sometimes merging with and obscuring them . Collar can extend into a tubular sheath .
7 to 10 lamellae on 60-70% of length of fully extended rhinophore. Stem smooth, transparent, colourless , but very often appears tinted when adjacent tissue seen through it  & . Stem often retracted, leaving only lamellae exposed . When entire rhinophore retracts, guard-tubercles may close over it .
Simple unipinnate , usually tilted backwards ; 9-10 in adults ; 6-8 in smaller individuals. Posterior gills usually smaller than the anterior ones. Translucent with fine black-brown specks; colour varies with density and extent of specks, from much darker than mantle  to, occasionally, concolorous  or lighter . Sometimes, dark line on main rib of each plume which meets others at anus . Gill pit surrounded by collar carrying about one spatulate guard-tubercle per plume ; often about 50% of tubercles noticeably larger than others. When gills retract, collar with tubercles may extend upwards to form sheath around them. Guard-tubercles have flat, smooth, inner face and slightly rounded, spiculose, outer face.
No linear oral tentacles, but very variable oral-lobe on each side of mouth . Lobe has cavity distally, but often difficult to discern. Mouth usually concealed in groove between oral lobes, but, when everted, is large thick rimmed circle.
When in motion, protrudes beyond posterior edge of mantle; many long internal spicules visible . Anterior margin bilaminate; no vertical notch . Translucent sole, yellow to orange-yellow, no pigment marks; shows grey-green, brown or bright yellow viscera and contrasts with underside of dark mantles . Occasionally, pale individuals have yellowish-white sole with very distinct spicules . Upper foot-surface colour similar to sole, often, also darker speckles .
Doris ocelligera, Mediterranean form.
- 1 Rhinophore lamellae pure white  to yellowish-white , distinctly different from mantle colour, markedly contrasting with frequent dull mantles.
- 2 Tubercles vary in size and shape , , , , but always widest at base.
- 3 Spawn, canary-yellow, not-waved, ribbon in loose coil of less than three turns , diameter usually under 10mm.
- 4 Large range of mantle colours: usually a dull or dark shade of brown, green or yellow , but occasionally bright yellow, bright orange-yellow , black-grey  or blue-grey .
- 5 Mature adults usually 6mm – 12mm long, extreme maximum 17mm.
- 6 Seen under magnification in good light, some spicules may protrude from tubercles .
- 7 Tubercles sometimes dark. Fine dark apical spot on tubercles on some specimens.
- 8 Two large spatulate guard-tubercles on rim of rhinophore pit .
- 9 Spatulate guard-tubercles at base of gill .
- 10 Gills unipinnate .
- 11 No linear oral tentacles, but very variable oral-lobe on each side of mouth . Lobe has cavity distally, but often difficult to discern.
Features of specimens over 20mm long. No web image of D. verrucosa under 20mm length viewed, so uncertain if these features apply to those small enough to be confused with D. ocelligera.
- 1 Rhinophores concolorous with mantle, or nearly so (SSF). Sometimes flecked with pigment.
- 2 Tubercles, vary from very small to very large (SSF), clubbed with narrower base [Dv4].
- 3 Spawn, white wavy ribbon in spiral of about 5 turns, (SSF). Diameter usually over 20mm.
- 4 Ground colour of mantle usually whitish (DORIS), yellow [Dv1], orange-brown [Dv2], light violet, greyish (DORIS) or pale flesh-colour, often with dorso-lateral bands of grey, brown or violet.
- 5 Adult length often 40mm, up to 70mm.
- 6 Tubercles smooth without protruding spicules, but adhering detritus may give rough appearance.
- 7 Tubercles may be darkened distally [Dv2], but rarely, if ever, fine black apical spot.
- 8 Two smooth large spatulate guard-tubercles on rim of rhinophore pit [Dv4].
- 9 Gill pit surrounded by collar carrying about one spatulate guard-tubercle per plume [Dv6].
- 10 Gills unipinnate.
- 11 No linear oral tentacles, but oral-lobe on each side of mouth. Lobe has cavity distally, but often difficult to discern.
Under intertidal stones  (Croatia, tidal range, <1m) to about 25m in Mediterranean. Diet uncertain; in Croatia, probably early growth stages of various sponge species, including membranous canary-yellow sponge sometimes found adhering to underside of rocks with D. ocelligera . Simultaneous hermaphrodite. Animals, 6mm and over, observed to breed June-October & January in Croatia . Canary-yellow, not-waved, ribbon of spawn  attached by edge in a loose coil of less than one turn to about two and a half turns , diameter 3-8mm. Ribbon about 15 ova wide. Cornish specimens illustrated  found under stone in intertidal pool that does not dry out.