POLYCERID^. S11 



IssA, Bergh. 



Si/n. — Colga, Bergh. 



Example. — /. lacera, Bergh. 



Frontal and dorsal appendages less developed than in Triopa, 

 mouth with triangular jaw. Lingual armature consisting of a 

 median row of plates, two strong lateral and seven external 

 plates. 



Heterodoris, Verrill and Emerfcon, 1882. 



Distr. — H. robusta, Y. and E. Martha's Vineyard, Mass. 



Form and general appearance like Triopa and Triopella, but 

 stouter and without any trace of gills ; mantle forming an 

 edge all around the back ; surface of the back with scattered 

 papillae ; a longitudinal crest between and behind the dorsal 

 tentacles, which are lamelloseand retractile, without sheaths, but 

 with a prominent fold of the mantle-margin in front of them ; 

 head large, rounded, with a free, thin margin, which has a flat 

 tentacular lobe on each side ; foot broad, rounded in front ; a 

 large opening, apparently the anus, on the right side between 

 the mantle and the foot, behind the middle ; verge, as protruded, 

 stout, cylindrical, swollen and rounded at the end, not armed ; 

 a short, stout, conical papilla just behind its base, and a lobe 

 below it ; farther back, nearer the anal (?) opening, there is a 

 small, simple opening, probably urinal. Odontophore broad, 

 with very numerous small, strongly hooked acute teeth in each 

 row, all similar except a few near the centre, which are less 

 curved and not so acute ; no median tooth. 



Thecacera, Flem., 1838. 



Distr — 3 sp. W. Coast of Eur. T. pinnigera, Mont, (xc, 4). 



Body limaciform, smooth ; mantle obsolete ; supracapital veil 

 indistinct ; rhinophores laminated ; no oral tentacles ; branchiae 

 non-retractile, with linear or tubercular lateral appendages. 

 Odontophore broad, with 12-14 plates ; the two inner on each 

 side bearing bicuspid spines ; no central plate. Small lateral 

 corneous jaws. 



Crimora, Aid. and Hanc, 1862. 



Distr. — C. pa.pillata, A. a.nd H. Guernsey. 



Body limaciform. Mantle nearly obsolete, forming a supra- 

 capital veil with branched appendages, and a papillated ridge 

 along each side of the back. Rhinophores laminated. Oral 

 tentacles tubercular. Branchiae non-retractile, placed about two- 

 thirds down the centre of the back. Tail short, without a dorsal 

 carina. Odontophore broad, bearing 26 or 27 spines on each 

 side, of three kinds : the inner one is large, hooked, and 

 bicuspid ; the next 5 or 6 are short and obtuse, and supported 

 on quadrilateral plates ; the rest very long, slender, and minutely 

 denticulated on the inner margin. No central spine. 

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