of P.J. VAN Beneden'), Souleykt'^), Gegenbaur^), Boas*) and Pelseneer"), it seems to inc of no 

 use to discuss the anatomy fully, as the various researches, which complete each other, have 

 been alreadj- sufficiently treated by Pelseneer, who at the same time demonstrated the 

 phylogenetic affinities of the subgenera. 



Creseis shows much resemblance with Limacma and is the most primitive subo-enus of 

 Clio. This is not only shown by the tentacular lobe on the hn, with which also some species 

 of Limacina are provided, but also by the tentacles, the left of which is very small and scarcelv 

 visible, which agrees with the one that is found in Limacina. The left tentacle is somewhat 

 larger in Hyalocylix, Styliola and Clio (s. str.) but even in this last subgenus it does n(jt nearly 

 attain the dimensions of the right one. I must observe, however, that I could onlv studv two 

 species of Clio (s. str.), so that my researches are not complete in this respect. Clio pyramidata 

 and Clio mspidata (Leyden Museum) were only at my dispo.sal. In this two species I remarked 

 between the tentacles a triangular lobe, directed forward ; it has been alread)- noted by Souleyet. 



As to the foot, the fins, the mantle and the pallial gland, I entirely refer to Pklsenekr. 

 Also with regard to the jaws, the radula, and the salivary glands. 



In all the species of the genus Clio, examined by me, I found a caecum, entirely 

 concealed in the liver, and opening at the right side of the stomach. In Clio (s. .<;ti'.) it is 

 somewhat swollen at the end. In Clio cuspidata I noticed a curious, bell-shajjed organ, strongl)- 

 attached to the intestine. Muscular fibres were seen on this bell, and, comparable with a 

 clapper, a dark, rounded organ was found within. The bad preservation of the specimens did 

 not allow me to stud\' the structure of this organ; most probably it is glandular and opens into 

 the intestine (PI. I, fig. i8). 



About the flexure of the intestine, the position of the anus in the various subgenera, 

 and the anal gland, I have nothing to remark. Gegenbaur's figure ") which represents the 

 intestine of Clio (Creseis) acicula as curved dorsally, has been reproduced in several works, 

 but the inaccuracies as to the organisation of this species were carried to the extreme by 

 Haller '), whose figure is wrong in almost every respect. Hornell's paper *'), treating on Clio 

 (Creseis) acicula, I could unfortunately not study. 



The various dispositions of the heart and kidney have been described by Boas ") ; 

 I, therefore, refer to his work. Gills are entirely wanting. 



The gonad is situated posteriorly; in Clio cuspidata, however, I have always found it 

 dorsall)- to the liver, and somewhat to the right. The duct exhibits an elongated swelling, but 

 its shape varies in the same species, the swelling being more or less pronounced and sometimes 

 divided into two parts, which is due in all probability to the maturation of the sexual products. 



i) Exercices zootomiques, Mem. Acad. Sci. Biux. vol. XII, 1839. 



2) Voyage de la Bonite, Zoologie, vol. II, p. 164 — 175. 



3) Unters. lib. Pterop. u. Hetevop., Leipzig, 18S5. 



4) Spolia atlantica, p. 54 — 57. 



5) Chall. Rep. LXVI, p. 13—16. 



6) Untcis. lib. Pterop. u. Heteiop., pi. 11, fig. i. 



7) Lehrb. vergl. Anat. p. 261, 1902. 



8) .-Anatomical Description of Cycscis, as a typical Pteiopod, Marine Zool., vol. II, (1895), p. 19- — 24. 



9) Spolia atlantica, p. 28 — 30. 



