630 



FRESH-WATER BIOLOGY 



29 (27, 28) Five transverse rows with thirteen large spines. Also two con- 

 spicuous lateral spines on each side near the end. 



Chaetonotus enormis Stokes 1887. 



Length 0.0846 mm. Of the thirteen large spines three stand in the ante- 

 rior row, four in the next, one at the extreme on each side in the next, three 

 in the fourth row, and one at the center in the fifth row. On each side 

 near the caudal process are two forked spines easily confused with those of 

 the five rows which they much resemble. Trenton, New Jersey. 



FIG. 978. Chaetonotus enormis in dorsal view. X 530. (After Stokes.) 



30 (12) Caudal process branching or notched. A transverse row of large 



spines near its base. Body surface rough. 



Chaeturina Ward. 

 Only one species known. 



Chaeturina capricornia (Metchinkoff) 1864. 

 A swamp animal not yet reported from North America. 



31 (i) No caudal processes. Posterior end simply rounded or lobed, in the 



latter case provided with long fine spines. 



Suborder Apodina. 



Reported from North America Family DASYDYTIDAE. 



Two genera described for Europe. 



Single North American genus Dasydytes Gosse 1851. 



Several species listed from Europe. 



Only species reported from North America. 



Dasydytes saltitans Stokes 1887. 



Length 0.085 nun. Head three lobed, distinctly separated from body by 

 slender neck, provided with two rows of cilia which vibrate alternately. 

 Four long heavy spines arise on each side near the neck and cross the back 

 obliquely. Two long straight spines, and two others long and curved, 

 project from the posterior end. This species swims rapidly but also moves 

 by sudden leaps to one side or the other, covering a distance equal to 

 double its length or more in a single jump. Trenton, New Jersey. 



FIG. 979. Dasydytes saltitans in dorsal view. X 410. (After Stokes.) 



