1879.] NATURAL SCIENCES OF PHILADELPHIA. 75 



between them short, equalling about one-sixth of the longitudinal 

 diameter of the ganglion; the gastro-cesophageal ganglia nearly 

 one-sixth of the buccal ones in size, with one very large and two 

 rather large cells, their stalk a little longer than the commissure 

 between the buccal ganglia. 



The eye has quite black pigment, and a yellowish lens. The 

 otocyst is situated some distance behind the eye, and is filled 

 with otoconia of the usual kind. 



The bulbus pharyngeus is of the usual size, about 5.0 mm. long, 

 3.0 mm. broad, 3.5 mm. high ; its form is as usual. The jaws ex- 

 actly as in the typical Ae. papillosa. The radula contained thir- 

 teen teeth, beside seven mature and two immature teeth in the 

 sheath, twenty-two altogether. The anterior plate was about 0.25 

 mm. broad, the posterior one about 0.75 mm.; yellowish horn 

 colored ; there were thirty-two denticles on the former and forty- 

 two on the latter. 

 2. Aeolidia papillosa, var. Pacifica, PI. I. f. 1-6. 



Colore e flavido albescens. 



Hab. Oc. Pacific septentr. (Chignik Ba}% Aliaska Pen.). 



Three specimens of this form were taken b} r Dall on mud flats 

 at low water in Chignik Bay, Aliaska, July, 1874. 



According to Dall the color of the living animal was pale yel- 

 lowish-white. 



The alcoholic specimens were all of nearly the same size, about 

 20.0 mm. long, 7-8.0 mm. broad, and 6-6.5 mm. high. The tenta- 

 cles and rhinophoria measured about 2.0 mm. in length, the papillae 

 of the back reached 3.0 mm. in length, and the breadth of the foot 

 5.0 mm. The color was yellowish-white, the papillae a little gray- 

 ish, and generally with white points. The viscera were not visible 

 through the side walls of the bod}-. 



The form of the animal was typical, somewhat depressed ; the 

 head rather large, the tentacles short and strong, stronger than 

 the rhinophoria, the eyes not visible through the wall of the back. 

 The foot was rather large, somewhat pointed behind, the anterior 

 margin straight, with a veiy distinct transverse groove. The sides 

 of the body rather elevated, with the genital papilla beneath the 

 eighth and tenth row of papilla:'. The back was naked in its 

 broadest part; in the much narrower side parts covered with 

 closely set oblique rows of papillae, which, on the hindmost parti 



