NO. 2062. NEW ROTATORIA FROM PANAMA— BARRING. 655 



PTYGURA LONGIPES (Wills). 

 Oedstes umhella Hudson, Journ. Royal Micr. See, 1879, p. 1, pi. 1. 

 From Rio Trinidad, above Agua Clara (10), few. 



PTYGURA PECTINIFER (Murray). 

 Oedstes pectinifer Murray, Journ. Royal Micr. Soc, 1913, p. 241, pi. 10, fig.14. 

 A single fully extended and numerous partially or completely 

 contracted specimens from Rio Ti'inidad, above Agua Clara (10). 



SINANTHERINA SPINOSA (Thorpe). 

 Megalotrocha spinosa Thorpe, Journ. Royal Micr. Soc, 1893, p. 151, pi. 3, fig. 6. 

 From a stagnant pool by the railroad, north of bridge over Black 

 Swamp, rare; pool near railroad, between Black Swamp and Gatun 

 (2), few. 



CONOCHELUS HIPPOCREPIS (Schrank). 

 ConocMlus volvox Ehrenberg, Abh. Akad. Wiss. Berlin (for 1833), 1834, p. 224. 

 In a collection from railroad bridge over Black Swamp (1), few; 

 pond west of Rio Chagres at Bohio (7), few. 



COLLOTHECA POLYPHEMA, new species. 



Plate 17, fig. 4. 



The body is of moderate length and nearly cylindrical; it tapers 

 gradually to the short foot and passes without noticeable constriction 

 into the corona, which has five short, blunt lobes, the dorsal being a 

 httle longer than the othere. The setae are confined to the tips of the 

 lobes. At the base of the dorsal lobe is a large, rectangular eyespot, 

 apparently formed by the fusion of the usual two, being twice as 

 broad as it is long; occasionally a trace of a dividing hne appears to 

 exist. The internal organs are normal, with the exception of two 

 round, thin, diskhke glandular bodies at the base of the corona, 

 not far apart and weU toward the doreal side. Their nature and 

 functions are unknown; it is possible that they may be the subcere- 

 bral glands, but it should be noted that no trace of these has been 

 found in any other species of the genus. Intra- vitam staining has not 

 been tried. The jelly-case is, as usual in free-swimming Collothe- 

 cidae, attached to the foot by a fairly long, hardened cement-thread, 

 corresponding to the peduncle of the sessile forms. The resting egg 

 is shown in the figure; the yolk-mass is covered with numerous, close- 

 set conical projections, which are surrounded by the outer shell. 



Total length, 240 fi. 



Type.—Csit. No. 16588, U.S.N.M., from Kenilworth, District of 

 Columbia, where the species is at times abundant. It has been found 

 also in ponds at Lakeland, Maryland, and at Fourmile Run, Virginia. 

 It was found in Isthmian collections, narcotized according to the 

 de Beauchamp method, from a pond at Bohio (7), common; Rio 



