ox THE ZOOLOGICAL STATION AT NAI'LES, 3G9 



a new order — ' Thecomedusas ' — ' animals composed of composite zooids, 

 medusiform with circular and radiating canals, included in a chitinous 

 rooted perisarc, which forms the tube within which they are retractile.' 

 Genus Stephanoscyphtis. 



In 1877 Professor F. E. Schulze published an extensive paper on this 

 animal (' Archiv fiir mikroscopische Anatomic,' vol. 13, 1877). 



He failed to find either the circular or longitudinal canals described by 

 Professor Allman. 



He gives the structure as being ectoderm, then a layer of longitudinal 

 muscular fibres, then a layer of supporting lamella, and then endoderm 

 throughout. He describes four ' Liingswalle,' which be says are made 

 by the endoderm folding round longitudinal ridges of supporting lamella. 

 There is also, he says, a hypostome which is simply a continuation of the 

 body-wall bent at right angles, and the four ' Liiugswiille ' continue along 

 the under side of this membrane and end at its free edge. 



He gives the number of tentacles as being variable, probably a mul- 

 tiple of four. 



He further describes four nose-like projections from the chitinous 

 tube into the interior, compressing the animal in the form of a Maltese 

 cross. 



The results he comes to are on the whole so very different from those 

 of Professor Allman that he leaves it an open question as to whether the 

 two animals are the same or not. 



In 1886 Professor Metschnikofi" in his ' Embryologischen Studien an 

 Medusen,' Vienna, 1886, p. 87, suggests that this animal might be a stage 

 in the life history of Nausithoe, partly on account of the fact that when the 

 young Nausithoe reach the Scyphistoma stage they produce chitinous tubes, 

 into which they retract with extreme quickness, and partly relying on a 

 paper of Kowalewski's (' Uutersuchungen iiber die Entwickelung der 

 Coelenteraten ' in Nachr. Ges. Fr. &c. Moskau, vol. 10, 2, Sep., p. 36) 

 in which that author says that he has seen Strobilation and also Ephyraj 

 given off by Siephanoscijphus. 



Professor Fol (' Die erste Entwick. d. Geryoniden Eier.' Jen. Zeit., vii., 

 p. 488) remarks that the larva3 of Nausithoe swim about for some weeks 

 in his aquaria without changing, except that thread-cells appear in their 

 ectoderm, after which they always die. This fact Metschnikoff also 

 remarks, but without mentioning that such would probably be the case, 

 as no doubt the young Nausithoe cannot develop without entering a 

 sponge. 



So far as I then knew, this was all the work that had been done on 

 Spongicola when, in the spring of 1890, in Professor Schulze's laboratory 

 in Berlin, I took up its further investigation. 



The points that seemed to me to want clearing up were : — 



1. "Were Stephannscyphus mirahilis and Spongicola fistularis one and 

 the same animal, or different species of the same genus, or were they 

 altogether different ? 



2. What was the exact position of this animal in the Zoological 

 series ? 



3. What was the exact significance of, 1st, the ' Langswalle ' of 

 Schulze; '2nd, the chitinous projections into the interior of the animal ? 



I began my work on material which Professor Schulze very kindly 

 procured for me from Trieste, which consisted entirely of specimens of 

 -fe'. hauriana well stocked with Spongicola. Unfortunately, although I 



1891. B B 



