Worms 245 



Callidina was found by Mr. E. Bethel in a small pool on South 

 Boulder Peak. According to Harring's Synopsis* it would fall 

 in the genus Macrotrachela, which includes species notable for 

 their handsome appearance, as suggested by the specific names 

 mirabilis, decora, formosa, etc., given to them. In the Pro- 

 ceedings of the U. S. National Museum, vol. 42, (1912) p. 181, 

 will be found full directions for collecting rotifers and preparing 

 them so that they are fit for study. It is thus possible for those 

 who are not specialists to contribute the materials whereby our 

 rotifer fauna may become known. 



Those who are using the microscope to examine rotifers and 

 other minute aquatic organisms will occasionally meet with very 

 singular elongated creatures, appearing to have whiskers like a 

 cat, a spiny or bristly body, and a bidentate tail. These are 

 Gastrotricha, an isolated class without near relatives. They 

 have been observed at Boulder, but the species was not determined. 

 Most of the American species have been described from specimens 

 collected by Stokes at Trenton, New Jersey, but other localities 

 would doubtless be quite as prolific if proper search was made. 



ANNELID WORMS 



The annelid worms, with segmented body, consist in our 

 fauna of the Oligochaeta or earthworms and their relatives, and 

 Hirudinea or leeches. The first of these groups includes some 

 animals which do not look at all like earthworms. One of these 

 is Aeolosoma, a microscopic freshwater worm with minute orange 

 spots. It is found occasionally at Boulder. Another family, 

 known as Branchiobdellidae (wrongly called Discodrilidae), con- 

 sists of peculiar small worms externally parasitic on crayfishes. 

 The species Cambarincola macrodonta and C. vitrea, both described 

 by Dr. M. M. Ellis, have been found in Colorado. The Enchy- 

 traeidae constitute a family of small annelid worms, found in 

 fresh water or damp places, and very widely distributed over the 

 earth. In 1917 Welch described Mesenchytraeus altus, collected 

 near Corona, close to the edge of a small lake on the east side of 

 Mt. Epworth. It occurred in moss and under old wood. When 

 preserved in alcohol it was about 1 7 mm. long. The true earth- 



*Syncpsis of the Rotatoria. Bull. 81, U. S. National Museum (1913). 



