1879] NATURAL SCIENCES OF PHILADELPHIA. 85 



The intestines are rather short, with a strong longitudinal fold 

 through its first half, with many fine longitudinal folds in the 

 anal papilla?. In the digestive channel were stems of Hydroidse 

 and different forms of Biatomacea?. 



The liver papilla? have a rather smooth surface. The bursse 

 cnidophorse rather short, pyriform, with masses of small cnidse 

 (fig. 12), partly of oval form and generally measuring in length 

 about 0.013 mm., partly shorter, staff-shaped, and rarely surpass- 

 ing the length of about 0.01-0.07 mm. 



The hermaphroditic gland is very 'large, the lobes and lobules 

 as usual; in the centre of the last were zoosperms; in the peri- 

 pheric (fig. 5) acini (which in very different numbers cover the 

 central part) were oogene cells. The anterior genital mass was 

 large, 2.2 to 4 mm., with a breadth of 1.2 to 2.75, and a height of 

 1.2 to 3 mm. ; the whole, in great part formed by the gland, mucosa 

 et albuminosa. 



The Spermatotheca seemed rather peculiar; it was sac-shaped, 

 rather short, and short-stalked ; the free end of the vas deferens 

 was only two or three times as long as the penis, somewhat 

 thicker in the middle, strong, continued (fig. 6a) through the 

 whole length of the penis. The retracted glans penis in its sheath 

 (fig. 6bb) which had a length of about 3.5 mm., as also the glans, 

 which was strong, short, sausage-shaped, with a round opening at 

 the end (fig. 6c). A layer of rather short sacculate glands filled 

 the end of the penis around the orifice. One of the drawings re- 

 presents the spawn of Ae. opalescens as a rather long corkscrew- 

 shaped coil of reddish hue. 



V. FIONA, Hanc. et Embleton. 



Fiona, H. et E. Forbes and Hanley, Brit. Moll., iii. 1853, p. x. Aid. and 

 Hanc, Monogr. Brit, Nudibr. Moll., Part VII., 1855, pp. 52, 53, fam. 

 3, PI. 38. R. Bergh, anatora. Unders. af Fiona atlant. Vdsk. Med- 

 del. fra naturh. Foren, i Kjobenliavn for 1857, pp. 273-337 (279-283 !), 

 1858, Tab. II.-III. R. Bergh, Contrib. to a Monogr. of the Gen. 

 Fiona, H., 2 w. pi. Copenhagen, 1859. R. Bergh, Journ. d. Mus. 

 Godef. 2te Heft, 1873, pp. 80-88, Tab. XII. fig. 4, 5. R. Bergh, Beitr. 

 zur Kenutn. der Aeolidiaden, I ; Verb. d. K. K. Zool.-bot. Ges. in 

 Wien, xxiii. 1873, pp. 605-610. V, 1. c, xxvii. 1877, pp. 823-824. 



Hymenaeolis, F. Costa, Annuario del Mus. zool. di Napoli, iii., 1866, pp. 64, 

 80 j iv. 1867, p. 28. 



Rhinophoria et tentacula subsimilia, simplicia. Papilla? (dor- 

 sales) cuti firmius afflxa?, elongata?, ab membranam branchialem 



