8 NEW- YORK FAUNA — MOLLUSCA. 



Doris illuminata. 



Doris illumi?iata. Gould, Invertebrata of Massachusetts, p. 4. 



Description. Animal prismatic, somewhat four-sided ; the back arched. Front of the 

 foot slightly dilated at angles. Upper lip full, and strongly pursed. A line of six tubercles 

 on each side, diverges from the front to each side of the tentacula, making the back at this 

 part of a four-sided form. Between these and the branchial tuft are four more tubercles on 

 each side, in parallel lines ; and then follow two on each side, much longer than the rest, of a 

 somewhat club-shaped form, followed by a few smaller ones towards the tail. Sides and 

 back dotted by several small tubercles. Gills fringed, arranged in a semicircle. 



Color. Pearly white or light dove-color, dotted with greenish. All the tubercles, tentacula 

 and gills, tipped with bright sulphur-yellow. 



Length, 0'75. Breadth, 0-25. 



This species was first noticed by Dr. Gould in Boston bay. I have adopted his description, 

 believing that the same species exists on our coast. 



FAMILY TRITONIDJE. 



The two upper tentacula retractile into a sort of sheath. A membranous veil, of greater or 

 less extent, above the mouth. Vent and sexual orifice distant, on the right side. Respi- 

 ratory organs variously formed, but arranged in two longitudinal series. 



Obs. This family, which corresponds with the Diceres of Blainville, now includes four 

 genera. The representative of one genus has been observed on our coast. 



GENUS TRITONIA. Cuvier. 



Body oval, oblong, convex above. Mouth with two lateral jaws, sharp, horny and denticu- 

 late on the edges. Foot long, canaliculate. Gills arborescent, arranged in a longitudinal 

 series on each side of the back. Sexual organs united on the right side in front. Vent 

 posterior to them, and near the middle of the back. 



Tritonia reynoldsi. 



PLATE V. FIG. 94. — (CABINET OF THE LYCEUM.) 



T. reynoldsi. Codthody, Bost. Jour. Nat. Hist. Vol. 2, p. 74, pi. 2, figs. 1, 2, 3, 4. 

 T. arborescens. Gould, Invertebrat. Mass. p. 5. 



Description. Body tapering to the tail, which ends acutely. Sides with numerous papillae. 

 Head short, depressed, orbicular, supporting three pair of gills. Mouth crescent-shaped, 



