Fam. 45.] NATURAL HISTORY SOCIETY. 128 



processes sulphur yellow at the tips. L. 30. — New Eng. Under 

 stones. 



3. POLYCERA, Cuv. 



Body slug-form ; mantle indistinct, forming a veil in front and 

 a tuberculated ridge on the sides; gills non-retractile, with two 

 or more lateral appendages. 



1. Polycera Lessonii, d' Orb. (Fig. 30). Animal slug-shaped ; 

 a sharp ridge or fringe along the sides of the back, having 6 

 tubercles on each side, and making the body quadrate between 

 the tentacles and the gills ; another row of tubercles extends along 

 the middle of the back ; head with 6 projecting points on each 

 side; gill plumes twice pinnate, 3 large and 2 small. Greenish 

 color formed by green dots; tubercles tipped with sulphur yellow. 

 L. 20-30.— N.Y. and north. 



2. Polycera Emertonii, Ver. Body small, elongated ovate, 

 somewhat angular,tapering backward to nearly a point, nar- 

 rowed a little at the neck ; dorsal tentacles rather long (length 

 equal width of neck), quite contractile but not retractile; gills 

 three, narrow, elongated, pinnate, subplumose, not finely divided, 

 curved backward, not retractile ; the pinnae few, alternate, gen- 

 erally incurved. Color yellowish-green to olive-green, varied to 

 lemon-yellow and dotted with darker ; foot, tentacles, gills and 

 dorsal papillae lighter greenish-yellow. L. 5-6; W. 1 ; H. IJ. — 

 New England. 



Suborder AIOLOBRANCHIATA. 



Branchia? variable, generally upon the sides of the back ; not 

 in a circle surrounding the anal orifice. 



Family 45. TRITONID/E. 



Animal with laminated plumose or papillose gills, arranged 

 along the sides of the back ; tentacles retractile into sheaths. 



* Four gill lobes projecting above the body, and tufted with gills upon their 

 inner sides 1. Seyllcea. 



* Gills very much branching and tree-like 2. Dendronotus. 



* Gills simple, club-shaped 3. Doto. 



1. oCYLL^EA, Linn. 

 Animal elongated, compressed ; foot long, narrow, and chan- 

 neled, adapted for clasping sea weeds ; back with two pairs of 

 wing-like, lateral lobes, bearing small, tufted gills on their inner 



