ANATOMY OF ACLESIA FREERI. 69 



show scarcely a trace of it. Another large papilla may arise 

 from the anterior edge of the head between the tentacles, but 

 does not appear to be so constant in its development as the 

 one previously mentioned. 



The tissues of the body wall and foot are delicate and trans- 

 lucent; this character combined with the pleasing coloration 

 render Aclesia freeri a much handsomer animal than most large 

 tectibranchs. Viewed with the naked eye, the ground-color 

 appears to be olive, but under a lens it is seen to be a very light 

 gray. Black dots and lines are so closely placed upon this that 

 the ground-color in most places is reduced to small irregular 

 dots, not distinguishable without a hand lens. The sole of the 

 foot is lighter in color than the body because the overlying 

 color is light brown, and its markings are much finer and more 

 evenly distributed than those of the body. 



The tips of the minute papillae, which have been mentioned 

 previously, are white, and thus a finely regular, whitish speckling 

 of the skin is produced. 



About and on the bases of the larger villi, the black markings 

 have the form of complete or incomplete rings, crescents, and 

 irregular flecks of vivid black. Between the bases of the villi 

 are numerous irregular areas where the black markings unite, 

 producing a fine black network inclosing minute gray areas and 

 the small white-tipped papillse previously referred to. The 

 black markings of the larger papillse become finer and finer 

 toward the tip; to the naked eye, no black is visible in the ter- 

 minal portion of the papillEe. The ground color, also, changes 

 from gray to tan, or even reddish-brown, with or without minute 

 dots of canary-yellow. The spots of the last-mentioned color 

 are widely distributed over the body of some specimens and 

 lacking in others. 



The brilliant eye-like spots of peacock-blue are subject to 

 extreme variation. In general, two fairly well-defined rows 

 may be distinguished. One row extends along the side of the 

 body, 10 to 20 millimeters above the foot; the other commences 

 back of the tentacle and passes along the back parallel with, and 

 about 1.5 centimeters distant from, the branchial fissure. Some- 

 times a third row appears, close to the margin of the fissure. 

 The color of these spots is very uniform. When examined 

 with a lens, the blue appears to be flecked with bright spots, 

 appearing like the metallic paints often used on children's toys. 

 The spots are ordinarily fairly uniform in size, and from 3 to 5 

 mill'meters in diameter. Occasionally one finds a specimen 



