(®gures 9f, 11f±h. Type micrograph: ®gure 11f)

Diagnosis. Notosolenus, cell pear-shaped, 15±18 Mm long, 9±13 Mm wide, with a longitudinal dorsal groove in left side, a ventral groove and a ventral ridge.

Description. Cell 15±18 Mm long and 9±13 Mm wide. Ventrally ¯attened and dorsally convex, cell outline pear-shaped. This species is anteriorly pointed or with a small collar at the anterior end of the cell and posteriorly rounded, but the raised central dorsal region may have a posterior point. The posterior lateral edges of the cell are thin and hyaline. This species has a median longitudinal groove, a ventral groove widening out towards the posterior end of the cell, and a ®ne median longitudinal ventral ridge parallel to the right margin of the ventral groove. The ®ne ventral ridge is hard to see but runs along the entire cell. The anterior ¯agellum is slightly longer than the cell and longer than the posterior ¯agellum. The recurrent posterior ¯agellum inserts into the anterior end of the ventral groove and varies from 0.5 to 1.2 times the cell length. It may lie in the ventral groove when the cell is gliding. The reservoir and the nucleus are in the right and left sides, respectively. Small globular granules occur beneath the cell surface. Rarely observed.

Remarks. This species is assigned to genus Notosolenus because it is a rigid, ¯attened euglenid with two ¯agella emerging from a subapical canal opening and no visible mouth. Notosolenus pyriforme is similar to N. canellatus (see Skuja, 1948) in general appearance, but can be distinguished because N. canellatus has three dorsal grooves, not one, and also has an anterior protrusion. It is similar to N. lashue Lee and Patterson, n. sp. in having one dorsal groove and in size, but is distinguished because N. pyriforme has hyaline lateral ¯anges and pear-shaped body and because N. lashue has a dorsal groove with a well-marked central ridge, and is ovate. Notosolenus pyriforme may be the same as N. canellatus sensu Patterson and Simpson, 1996 described from Western Australia.