of the Bay of Naples. Ill 



not terminate with an adhesive disc, but the posterior pole of 

 the hody has the form of a hemisphere, which is beset with a 

 row of small denticles, between which the viscous glands dis- 

 charge themselves. In the Bay of Naples. 



1. Paraseison asplanchnus, sp. n. — Average size of the 

 adult female 1 millim. Without true rotatory apparatus, 

 but with four tufts of tactile set^ standing round the buccal 

 aperture. 



2. Paraseison nudus, sp. n. — Size 0-6 miUim. Head 

 without any trace whatever of a rotatory apparatus, and also 

 without buccal tactile set^. It also becomes attenuated in 

 front, so that the buccal aperture comes to be situated at the 

 apex of a small cone. 



3. Paraseison proboscideus, sp. n. Size 0'75 millim. 

 Head without any trace of rotatory apparatus, without tactile 

 setai at the mouth, but with a small proboscidiform eversion 

 of the skin, situated above the buccal aperture, which serves 

 as a tactile organ. Rare. 



4. Paraseison cih'atus, sp. n. Size about 1 millim. Assists 

 in the transition to the genus Seison, inasmuch as the rota- 

 tory apparatus is developed as in that genus, and further there 

 are, on the ventral surface of the trunk, two longitudinal 

 streaks composed of numerous parallel muscular fibres. Not 

 uncommon. 



With these two better-known genera is to be arranged the 

 still insufficiently investigated 



Genus III. Saccobdella, Van Beneden & Hesse. 



Saccobdella nehalue, Van Ben. & Hesse. Length 2-3 

 millim. The abdomen terminates in two pedunculate sucking- 

 discs. Neck composed of five segments of about equal 

 leno-th, tail of four rings. Buccal aperture on the lower sur- 

 face of the head, not far from the anterior margin. _ The in- 

 testine is said to traverse the whole body in the median line. 

 Colour of the body a very light blue. The ova possess a 

 small stalk, and several of them may be united to form a 

 bush-lik-e group. In the North Sea. 



Postscript. — The assertion formerly made by me (Zeitschr. 

 f. wiss. Zool. Bd. xliii. pp. 230 et seqq.) , and to which I have 

 referred in the preceding memoir, that the sexual organs of the 

 female Philodinaias are not divided into a germigene and a 

 vitelligene, has recently proved to be a mistake. Soon after 

 the completion of the manuscript of this memoir, I found the 

 germigene in some Philodinsege which were better suited to 



