296 GASTEROPODES. 



3. DORIS (GoNioDORis) NODOSA. Plate XLII. Figs. 8, 9, 10, 11, 12, 13, 14. 



The two preceding animals, the Doris verrucosa and the Doris argo, 

 are distinguished, 1. By a cloak covering the whole body, unless a small 

 portion of the posterior extremity. 2. By two tentacula rising from the 

 surface towards the anterior extremity. 3. By the site of the branchial 

 apparatus on the back, wherein it is completely retractile. 



The present subject corresponds in this last feature only. 



All the parts are of different formation, some of them not far re- 

 moved. 



Length an inch ; breadth half an inch ; body thick and fleshy. Sole 

 somewhat lanceolate ; shoulder round ; extremity slightly obtuse. Head 

 broad, the corners forming two tentacular processes by duplication of 

 the skin. Two cornicula rise from the anterior surface of the cloak. 

 The branchiae, usually eleven in number, are flattened organs, rise from 

 the back, and are susceptible of being withdrawn into the body. The 

 margin of the cloak is like a flounce, in projecting somewhat over the 

 body and its curvatures. The whole animal is of a soft fleshy aspect, 

 and fine carnation colour ; the surface smooth, with some white speckling, 

 also reaching the sides, and apparently from the lowest tubercles. 



This animal seems to feed on the Ascidia papilla, from which is cer- 

 tainly derived the reddish colour, rendering it a fine and delicate object. 

 This is more obvious when viewed from below. 



Two large and beautiful specimens having occurred on the 1st of 

 July, they were committed to the same vessel. Their union took place 

 on the 2d and 4th of that month, the head of one being diverted up- 

 wards, and that of the other downwards, so that both were reversed, as 

 in the Tritonia verrucosa. Spawning ensued on the 4th and on the 18th 

 of the same month. In both instances an irregular circular ring of spawn, 

 about seven lines in diameter, and forming a rope above a line thick, 

 was deposited on the side of the vessel, just below the surface of the 

 water. On a third occasion, a rope was produced on the 3d of March, 

 near the neck of a bottle, which would have extended three inches if in 



