The Microscope. 3 



appendages. The lower or ventral surface is a flat and nearly level 

 plane extending beneath the enth'e body, and bearing two or more 

 longitudinal bands of cilia. The mouth opens on this surface near 

 the frontal border, the anus at the opposite extremity between the 

 caudal branches. The animal also possesses an oesophagus, intestine, 

 ovary, muscular, nervous and water-vascular systems, with two 

 caudal glands, and, in one species at least {Ch. larus), a sub-intes- 

 tinal gland said to represent the testes. All the species are repro- 

 duced by eggs, none, as Prof. Fern aid remarks, being parasitic at 

 any stage of their development, so far as now known. 



These little animals have given the systematist a heap of 

 trouble. They have been tossed about fi'om Rotifera to Infusoria 

 and Turbellarian worms, and finally to a distinct order, where they 

 probably belong. Ehrenberg classed them among his Rotifers, and 

 Gosse, writing twenty years ago, offered an extended argument to 

 show that they belong where Ehrenberg had placed them, rather 

 than among the Turbellaria to which they had been relegated by 

 Schulze writing ten or twelve years before Gosse. Dujardin included 

 them among his Infusoria; Met^chnikoff, in his order, Gasterotricha; 

 Glaus includes the genus in two groups of small animals allied to 

 the Rotifera ; Huxley says it probably belongs to an annectent 

 group between the Rotifera and the Tui'bellaria ; and finally 

 Biitschli also elevates the genus into an order which he calls the 

 Nematorrhyncha, placing it between the Nematoda and the Arthro- 

 poda, of these last making two limbs to that branch of the genealog- 

 ical tree from which springs the Rotatoria twig. 



There are in our waters several species, and although all of 

 them may have been observed, none of those found here, with the 

 exception of Ehrenberg's Ch. larus and Ch. maxhnus, have been 

 recorded either in this country or in Europe. My field has been 

 limited to the region about my own home, and has perhaps not been 

 thoroughly explored ; it is therefore more than probable that many 

 besides those to be referred to here await the search of the patient 

 microscopist. To collect them, gently scrape the surface of the oozy 

 bottom of shallow ponds, as Dr. Leidy recommends for the gathering 

 of Rhizopods ; and let the collector also sweep his dipper under the 

 lily leaves, and among the submerged stems of the Nuphar, and he 

 will not be disappointed. 



The "swollen head," as a rule, is obscurely triangular, but with 

 three or five distinct rounded lobes, the posterolateral enlargements 

 merging into the origin of the neck-like region. The frontal 



