FROM RHODESIA, LOPHOPODELLA THOMASI, 49 



only varieties of Plumatella repens. It has been stated, with 

 much appearance of truth, that though the extreme forms differ 

 markedly from the type, yet in every case a number of inter- 

 mediate varieties have been found connecting them with 

 Plumatella repens. Monsieur J. Jullien (15), in 1885, was the 

 first to reduce all European Plumatellas to the one species 

 PI. repens', but he strangely accepted all the American species. 

 Professor Kraepelin (17), unable to find a way out. of this maze, 

 deposed all the Plumatellas from their specific rank, and created 

 out of them two new types, PI. polyforma and PI. pr'mceps, to 

 which he subordinated the principal varieties. These types are 

 mainly distinguished by their statoblasts, whether broad oval 

 or elongated oval in shape. Some more recent investigators have 

 accepted, whilst others have rejected, this arrangement. For 

 the creeping Plumatellas, with soft, gelatinous tubes, M. Jullien 

 has proposed the new name Hyalinella. Mr. Ridley's Australian 

 Lophopus leyidenfeldi (19) seems to me to belong to this genus. 

 M. Jullien (15) has also renamed the well-known Lophopus 

 crystallinus into L. trembleyi, which is quite inadmissible according 

 to the rules laid down by the International Congress of Zoology. 



As regards their geographical distribution, most of the species 

 have been found in England, America, Germany, France, 

 Bohemia, Hungary, and Russia — that is, wherever they have 

 been really looked for. Isolated species are known from India, 

 Australia, Japan, South America, Egypt, East and West Africa, 

 and now from Rhodesia, but it seems clear that it only requires 

 a systematic search to find them in most countries where there are 

 lakes, pools, canals, or slow-flowing streams. 



Coming now more particularly to the species which forms the 

 subject of this paper, I had only the statoblast to guide me in 

 my search for its nearest allies. It is well known, however, that 

 these resting or winter buds, produced only by the phylactolae- 

 matous* fresh-water Polyzoa, are very characteristic of the 

 different species, and are mostly quite sufficient by themselves to 

 establish the identity of the animals to which they belong. 



The statoblast consists of a central capsule surrounded by a 

 dark brown ring of air cells, called the annulus, which enables the 

 structure to float on the surface of the water. In Cristatella 



* Which means possessed of a fleshy tongue, or epistome guarding the 

 entrance to the mouth. 



Journ. Q. M. C, Series II. — No. 54. 4 



