FRESHWATER NEMATODES FROM LOCH NESS 



9 



Male, (n = 1). L = 960 pm; a = 44.2; b = 7.1; c = 5.1; c' = 12.8; 

 gubernaculum = 6.0 pm; spicules = 22.6 urn; tail = 188 pm. 



Similar to female; body slightly sinuous and curved distally, also 

 narrowed in region of cloaca - possibly an artefact as the body is 

 slightly twisted in this region. Bursa 38 urn long, with crenate 

 borders; cloacal lips protruding. Tail tip finely rounded. 



Distribution and habitat. 

 and freshwater habitats. 



Cosmopolitan, found in damp soils 



REMARKS. This species was recently redescribed by Brzeski ( 1 997 ) 

 and these specimens fall well within the range of measurements 

 presented for F. thornei. The height of the head is perhaps slightly 

 lower, but this is not thought to be of any significance. 



Filenchus sp. 1 



Fig. 9 



Material examined. Foyers Plateau: 159 m; core 14. 2 99. Deep 

 North Basin: 211 m; core 22, 1 9. 



Horizon. Core 14, (1-2 cm; 3-4 cm). 



Females, (n = 3). L = 53 1 pm (439-615); a = 40.6 (39.7—41 .8); b 

 = 6.0 (5.5-6.5); c = 3.4 (3.2-3.6); c' = 18.5 (15.8-20.2); V = 58.6 

 (57-60); V = 83.3 (82.6-84.5); tail/V-a = 2.5 (2.2-2.7); tail = 157 

 urn (132-191.5). 



Head 5.0-5.7 urn wide at base with two annules. Amphids 

 sinuous. Annules about 1 .6 urn wide at mid-body. Lateral field (only 

 evident in two specimens) with four lateral lines, the inner two being 

 very faint and close to outers. Spear indistinct, slender, 9.6 urn long 

 with small rounded knobs about 1 .3 urn wide. Excretory pore 64 urn 



(56-73) from anterior. Oesophagus 85 pm (74-94.2) long; median 

 bulb with poorly developed valves at 40.4% (35^15.6) of oesopha- 

 geal length. Anterior genital branch 163 pm (115-198) long. 

 Spermatheca offset, 27.7 pm (22.4-32) long. Postuterine sac 8.9 pm 

 (8.3-9.6) long. Vagina 7.0-7.7 pm long, gently inclined anteriorly 

 with thickened walls. Tail terminus pointed to finely rounded. 



Remarks. The specific identity of these females is uncertain. 

 They show affinities with F. facultativus described above and may 

 be conspecific. However, in these nematodes the spear is slightly 

 longer and the walls of the vagina are slightly thickened. 



Filenchus sp. 2 



(Fig. 10) 



Material examined. Foyers Plateau: 157 m; core 14, 1 9. 



Female, (n = 1 ). L = 625 pm; a = 40. 1 ; b = 5.2: c = 5.5; c' = 9.0; 

 V = 65.8; V ' = 80; tail/V-a = 1 .0; tail = 1 08 pm; 



Head 5.7 pm wide at base. Amphids not observed. Annules fine, 

 1.3 pm wide at mid-body. Lateral field with four lines, inner two 

 faint. Spear indistinct, 9.3 pm long with small basal knobs about 1.3 

 pm wide. Excretory pore 82.5 pm from anterior. Oesophagus 119 

 pm long; median bulb ovoid, valves weak at 40.7% of oesophageal 

 length. Anterior genital branch 175 pm long; spermatheca axial, 

 about 22 pm long, with rounded sperms about 1.9 pm in diameter. 

 Postuterine sac 6.4 pm long, occupying 41 % of corresponding body 

 diameter. Vagina about 5.8 pin long, perpendicular to body axis. Tail 

 terminus finely rounded. 



Fig. 9 Filenchus sp. 1. A-F, female. A. oesophageal region; B. head 

 showing amphid; C, lateral field; D, tail tip; E, habitus; F. posterior end 

 of reproductive system. Scale bars a = 10 pm, b = 100 pm. 



Fig. 10 Filenchus sp. 2. A-E, female. A, oesophageal region: B. habitus; 

 C. lateral field: D, tail; E, posterior end of reproductive system. Scale 

 bars a = 20 pm, b = 100 pm. 



