262 The Microscope. 



of the body; head furnished with two club-shaped organs resembling- 

 antennge. Length j^ inch." From 1851 up to 1876 Dasydytes 

 received no further attention; it was not even seen, so far as I know. 

 Then Ludwig in Zeitschrift filr ivissenschaftliche Zoologie, for 1876, 

 republished Gosse's diagnoses. Further than this the little creatures, 

 so far as I am aware, have not been even referred to, except by the 

 Micrographic Dictionary which also only reprints Gosse's concise 

 descriptions; and if either of the species from English waters has 

 been seen since their discoverer first found them, there is no record to 

 that effect. No illustrations were published by Gosse nor by Ludwig; 

 and no supplementary observations have been offered in reference to 

 structure, habits or development. The newly-discovered animals- 

 were at the time classed by Gosse among the Rotifers. They belong, 

 however, in the group with Chcetonotus. 



More than a year ago it was the writer's good fortune to capture 

 a single individual of an undescribed species of Dasydytes, the first, 

 so far as known, to be observed in this country. At the time, its 

 structure was not entirely mastered; and although I have recently 

 taken others of the species from the same locality, I fear that the 

 description must still be somewhat incomplete, as the little creature 

 is peculiarly difiicult to study. 



In form the species referred to bears a remote resemblance to 

 Cfuetonotus, differing in its shorter body, the presence of a more 

 distinctly formed neck, and in the absence of the fiu'cate posterior 

 extremity. The coloi'less and transparent body is irregularly ovate, 

 and less than three times as long as broad. Its internal structure is- 

 not very widely different from that of Chcetonotus, but in general 

 appearance the animal lacks the graceful form and attractive move- 

 ments of the latter. The absence of the two tail-like prolongations 

 so conspicuous in some of the Chsetonoti detracts from the beauty 

 of Dasydytes, its posterior extremity being simply rounded or con- 

 vexly truncate: and its movements are much less smoothly gliding^ 

 and facile. The habitat of both animals is the same, being chiefly 

 near the bottom of shallow ponds, although, if the surface be covered 

 with Lemna, both will probably be taken with those plants whose 

 lower siirfaces they search for food, or in whose abundant rootlets 

 their little bodies may become entangled. 



The head of the present species, and presumably of all, is 

 flattened and distinctly three-lobed, the anterior lobe being the small- 

 est and least rounded and bearing on the frontal border a colorless, 

 apparently chitinous plate or cephalic shield. Both surfaces of the 



