480 WILLIAM NICOLL. 
fresh investigations in connection with these species, and the 
notes which are herewith given are only such as to correct a 
few obvious errors. 
Sub-family, Micropuattin® Ward, 1901. 
Genus, Spelotrema Jigersk., 1900. 
This genus includes the species Sp. pygmeeum (Levin.), 
Sp. claviforme (Brandes) Mihi., Sp. simile Jagersk., and 
Sp. excellens Mihi. A fifth species, namely, Sp. feriatum 
Mihi, has been found to belong to the nearly allied genus 
Levinseniella. The genus may require to be further 
restricted to three species, for Sp. claviforme (Brandes) 
Mihi is only doubtfully distinct from Sp.pygmeum. ‘The 
characters of the four species may be briefly summarised as 
follows : 
Spelotrema pygmeum (Levins.) Odhn. 
Odhner, “ Trematoden des arktischen Gebietes” in ‘ Fauna 
Arctica,’ iv (1904), pp. 315-317, fig. 1, 2a. 
Length 3-5 mm. Maximum breadth -2-3 mm. Club- 
shaped. Diameter of suckers about ‘04-05 mm., but oral 
sucker always slightly larger than ventral sucker. Ventral 
sucker a third of the body length from the posterior end. 
Intestinal diverticula reaching posterior border of ventral 
sucker. Genital body only half the breadth of the ventral 
sucker. Ductus ejaculatorius short and direct. Testes com- 
paratively large. Uterus fairly voluminous, but not obscuring 
testes. Ova ‘021-023 by °012 mm. Habitat, Somateria 
mollissima, Somateria spectabilis, Oidemia nigra, 
and Oidemia fusca. 
Spelotrema claviforme (Brandes) Mihi (Pl. 10, fig. 18). 
Nicoll, “ Trematode Parasites of British Birds” in ‘ Annals 
and Mag. Nat. Hist.,’ (7) xx, (1907), pp. 254-255. 
Length :2-4 mm. Maximum breadth ‘15-20 mm. Club- 
