Hood — On the Rotifera of the County Mayo. 685 



to the middle of the body ; the large red eye is situated on the 

 anterior dorsal part of the brain. The foot-opening of the lorica 

 is (as correctly represented in our fig. 4) oblique from right to 

 left, allowing the foot and toes to bend only to the right and 

 neither dorsalwards nor ventralwards. The whole lorica has a 

 very slight twist to the right.] 



Coelopus porcellus, Gosse. A few examples of this plump species 

 occurred in sediment from a lake in the Knappagh district, and 

 in a muddy pool on the face of a hill in the Croagh-Patrick range 

 near Westport, 1891, '92. 



C. minutus, Gosse. A number of examples of this dwarf Eotifer 



were found in water collected in a lake at Castlebar in 1891, 

 associated with Volvox glohator ; also in the mill-dam at "West- 

 port, 1894. 



Family Dinochaeid^. 



Binocharis pocillum, Ehrenb. A number of examples of this species 

 occurred in a marsh-pool near "Westport in 1889, and in Castlebar 

 Lake and bog, 1891. 



D. tetractis, Ehrenb. Many examples occurred in the lakes and bog- 



pools near Westport in 1891, '92, '94. 



Polychaetus eoUinsu, (Gosse). Binocharis colUnsii, Gosse, Intell. 

 Observer, x. p. 269, 1866; H. and G., ii. p. 72, pi. xxi. 3. 

 Polychaetus spinulosus, Archer, Quarterly Journal Microscopical 

 Science, viii., p. 72, 1868. 



(Plate XXII., figr. 5.) 

 A few specimens of this rare species occurred in a small 

 lake two miles east of Westport in 1894. Mr. Archer records 

 it from the Carrig and Gallery districts. 



P. subquadratus, Perty, Z. Kennt. kl. Lebensformen, Bern, 1852, 

 p. 45, pi. i. 6fi5. Cf. C. Ternetz, Rotat. d. TJmgebung Easels, 1892.. 

 Western, op. cit. 



(Plate XXII., fig^. 6.) 



Mr. Gosse, in the Monograph of the Rotifera, expresses an 

 opinion that his Binocharis coUinsii and Perty' s Polychaetus 

 subquadratus are identical. This view cannot be upheld ; there 

 are significant and persistent differences between the two forms. 

 The outline of P. subquadratus is nearly square, and less 



