'680 Proceedings of the Royal Irish Academy. 



P. deeipiens, Ehrenb. This species occurred, not rarely, but in small 

 numbers, in marshes and in a quarry-pool near Westport, 1889, 

 '91, '94. 



P. ffihia, Ehrenb. This small species seems to be scarce. My obser- 

 vations were confined to two examples from a marsh-pool near 

 "Westport. 



P. petromyzon, Ehrenb. On two occasions, in 1891, '92, I have 

 found this species abundantly in a small lake near "Westport. It 

 occurred on twigs of Myriophyllum, thickly covered with 

 Yorticellidse, on which animals Ehrenberg believed it to be 

 parasitic. 



P. tiyrtdia, Grosse. On each of my four visits to the west I met with 

 a few examples of this distinctive species near Westport. 



Hertwigia parasita, Ehrenb. Notommata parasita^ Ehrenb., Die In- 

 fusionsth., 1838, p. 426, pi. l., 1. Proales parasita^ H. and G., 

 ii. p, 89, pi. xviii. 1. Sertwigia volvocicola, Plate, Jen. Zeitschr., 

 1885, p. 26, figs. 7, 8. I met with a large number of examples 

 of this species in Volvox glohator in. Castlebar Lake, 1891. The 

 affinities of the creature are doubtful. Although it was assigned 

 to Proales by Mr. Gosse in the Monograph, I am convinced that 

 it does not properly appertain to that genus, from the species of 

 which it differs (1) in lacking foot and toes; (2) in possessing a 

 conspicuous fleshy, finger-shaped " antenna." I am somewhat 

 inclined to think that its true affinities are with Sacculus, in spite 

 of its possessing an alimentary canal, which, in the latter genus, 

 has become atrophied : but in the meantime we may place it 

 apart under the name Hertwigia, a name coined for it by Dr. 

 Plate, who was unaware that the species was already known. 

 The creature is more interesting than graceful. It is to be found 

 within the beautiful spheres of Volvox glolator, from which it 

 derives its sustenance, and in which it deposits its eggs. After 

 laying its eggs it eats its way out of the Yolvox colony, leaving 

 its eggs to hatch. It then swims through the water until it 

 finds a suitable Volvox in which to make a new home, and, 

 effecting an entrance by eating a hole in the cuticle, there it lives 

 in ease and plenty. 



Furcularia forficula, Bolton. I observed six examples in a bog-pool 

 near Westport in 1891, a few more in the same spot in 1892, and 

 a few in sediment from a neighbouring lake in 1894. 



