APPENDIX. 



When this work was being printed it appeared necessary to add some remarks : 



I. During my stay at the Zoological Station at Naples I had an opportunity to get a look into 

 GioËNi's work, mentioned on p. 34. The author proposes on p. xxiv and p. xxv that the 

 animal, which without any doubt must be Cavolinia tridcntata, shall be called after him. 

 II. In August 1903 appeared a study by Pelseneer on the Mollusca of the Belgian Antarctic 

 Expedition (Résultats du Voyage du S. Y. Belgica, Mollusques par P. Pelseneer "Pteropoda", 

 p. 29 — 31). On p. 30 we find that the operculum of Liinaclna antarctica is coiled to the left. 



III. In the Zool. Anz., Bd. XXVII, N" 10 and 11, Meisenheimer describes, after having studied 

 sufficiënt material, the anatomy of Desmopterits. A definite opinion with respect to the 

 systematic place the author does not give •, yet he seems inclined to think that Dcsinoptcrus 

 must be reckoned among the Gymnosomata. 



IV. While printing this paper, I became acquainted with the very recently published study by 

 Kwietnewski, " Contribuzione alla conoscenza anatomo-zoologica degH pteropodi gimnosomi del 

 mare mediterraneo, Roma, 1903". Besides an extensive systematic and anatomical treatment 

 of the whole group, important information is given with respect to the Gymnosomata, 

 observed by the writer in the Strait of Messina. Some larval stages especially are of 

 importance and among these must be mentioned Thliptodon, which had not been found 

 ao-ain since Gegenbaur (1855). The author identifies Thliptodon with Pteroceanis Meisen- 

 heimer. To my inflnite regret I have not been able to take into account the results of 

 the paper above-mentioned, as my researches had come to an end already before. 



