370 KEPORT — 1891. 



was enabled to make out some points with regard to the structure and 

 anatomy of the animal, the matei'ial was in too bad a condition to give 

 very good results. 



Professor Schulze made several attempts to pi'ocure me living material 

 from Trieste, but the specimens on every occasion arrived in a half- 

 macerated condition. Finally, at the end of the summer, Professor 

 Schulze advised my going to Naples. This, owing to the great kindness 

 of the British Association in placing their table at my disposal, I was 

 enabled to do. 



When I arrived at Naples and stated the object of my visit, Professor 

 Dohrn informed me that Professor Paul Mayer and Signer Lo Bianco 

 had during the summer made a discovery regarding Spongicola. 



1 was immediately introduced to Professor Mayer, who, with the 

 greatest kindness, gave me full particulars of everything he had done, 

 and to whom my most hearty thanks are due for nmch kind assistance 

 and many valuable hints. 



1 also here wish to express my indebtedness to Dr. Eisig, Signer 

 Salvatore Lo Bianco, and all the other assistants at the Station, for their 

 extreme kindness to me during my stay in Naples. 



While I was there in November, Dr. Mayer and Signor Lo Bianca 

 published (in the ' Zoologischer Anzeiger,' No. 851, 1890) a short paper, 

 * Spongicola und Nausithoe,' completely answering my No. 2 query. 



On June 20 they saw the Ephyrfe being given off fi-om the Spongicola^ 

 which were nearly all in Strobila stages. 



These larvfe were kept and fed until, at the end of four days, they 

 reached, without doubt, the stage which Professor Claus has described 

 and figured as a young Nausithoe (' Untersuchungen liber die Organisa- 

 tion und Entwicklung der Medusen,' Prag und Leipzig, 1883, PI. 7, 

 Fig. 48), thus proving that Spongicola is the Scyphistoma stage of 

 Naiidtlioe. 



From this, as Dr. Mayer pointed out to me, another question arose, 

 namely, as to whether Professor Haeckel is right in his work on 'MedusiB' 

 (1879, p. 486), in saying that all the three species of Nausithoe hitherto 

 described, viz., N. punctata, Koll., N. marginafa, Koll., and N. albida, 

 Gegenbaur, are the same species. 



It seemed to me that this might be settled with regard to whether 

 there were more than one species of the Scyphistoma form. I therefore 

 turned my attention to this subject, and found that, 1st, there was the 

 difference in form already stated ; 2nd, the tubes that grow in the solid 

 sponges, and are straight, are much lighter in colour than the more curved 

 ones in the hollow Esperice ; 3rd, that the Spongicola with the straight 

 tubes have generally the yellow crystals in their tentacles (I saw none in 

 the body-walls), described by Kolliker, in the walls of the bell of N. 

 punctata. These I have never seen in the curved-tubed animals, but the 

 difficulty of seeing them at all may account for this, as it is only when 

 the animal is in a certain light that they are visible. 



Dr. Mayer and Signor Lo Bianco found them always present in the 

 Ephyri3e. 



On the whole I am inclined to think that the differences I observed 

 are not sufficient to enable me to say with any certainty that there is 

 more than one species. I was, unfortunately, unable to study this ques- 

 tion from its other side, as only one specimen of Nausithoe Avas captured 

 during my stay in Naples. 



