C. F. ROUSSELET OX TROf'ITOSPli.EP.A SOLSTTTTALIS. 101 



For thirty years notbing more was seen of this animal, until 

 Surgeon Gunson Thorpe had the good fortune of finding it again 

 in January 1889 in Fern Island pond of the Botanical Gardens 

 at Brisbane, Australia, and of also discovering the male, which 

 he described in a paper published in the " Journal R.M.S.," 1891, 

 p. 301. 



In August 1892 Surgeon Gunson Thorpe was stationed in 

 Chinese waters, and his ship having gone up the Yangtsze Kiang 

 as far as Wuhu, some two hundred and sixty miles from the 

 coast, he there examined the water of some irrigation creeks and 

 ponds, and discovered a new species of Trochosjyhcera, in which 

 the ciliary wreath encircles the body as the Tropic of Cancer 

 encircles the earth, dividing it into two unequal segments. He 

 therefore named his species T. solstitialis, and described it in 

 a paper which appeared in the "Journal R.M.S." of 1893, 

 p. 147. 



In August 1896 the same species was found by Dr. C. A. Kofoid 

 in the Illinois Eiver, in America ; and last summer a few 

 examples were again taken by Mr. H. S. Jennings in a pond 

 close to Lake Erie, America ; and this gentleman has been good 

 enough to send me the mounted specimen, wiiich he j^repared 

 according to my method, now exhibited for the first time in this 

 part of the world. 



The anatomy of the animal is extremely simple and beautifully 

 displayed, all the organs, usually so indistinct and closely packed 

 together in rotifers, being here spread out and suspended in the 

 transparent sphere in the most delightful manner. The ciliary 

 wreath encircles the sphere above the middle, leaving the usual 

 dorsal gap, and dividing it into two unequal segments, the larger 

 oral segment containing all the organs, and the smaller aboral 

 segment having nothing at all. Close below the wreath on the 

 ventral side is the mouth and mastax ; a long thin 03Sophagus 

 leads into the alimentary canal, which is suspended in the centre 

 of the sphere. This canal has about its middle a single small 

 knob-like outgrowth or gland, makes half a corkscrew turn, 

 and ends in a cloaca which apparently opens also on the ventral 

 side. Now, in all other Rotifers without exception having a 

 cloaca this organ opens on the dorsal side. Surgeon Gunson 

 Thorpe was so impressed by this anomaly in his new species that, 

 rather than admit that this was a new departure, he preferred 



