414 Mr. E. A. Baylis on a 



apparently laid when the contents have not advanced beyond 

 the two-cell stage of segmentation. 



Table of Measurements of¥. sianiensis. 

 (All measurements in millimetres.) 



6. 2- 



Leugtli 15-9 16-6 



Thickness (maximum) 0*8 G'8 



Length of tail 0'9 1-4 



,, niouth-cavity 01 0"1 



,, anterior portion of cesophagus. O'll 0"13 



,, prebulbar swelling 0''27 0'3 



(Esophageal bulb, length 03 0-3o 



„ ,, transverse diameter . . 0'32 0'37 

 Distance from anterior end to end of 



oesophagus (including bulb) 2'4 2-6 



Distance from anterior end to nerve-ring . 0'6 0"6 

 ., „ „ cervical pa- 

 pillae 1'32 1-5 



Spicules, length 086 



„ breadth 0-09 



Accessory piece, length 0'2I 



Distance from tip of tail to vulva . . 6"0 



,, „ ,, caudal pa- 

 pilla (?) 1-0 



Size of ova O-lGoxOlOTo 



A generic diagnosis, based on the characters of the two 

 known species, may now be given : — 



Falcaustra, Lane, 1915. 



Ascaroidea [? Oxyuridse], ^leromyariaii. Mouth with 

 three equal lips, each bearing two prominent papilhe, tiie 

 jiulp of each papiUa giving off an inner branch which 

 ])robably ends in a small sensoiy pajnlla on the inner surface 

 of the lip. Mouth-cavity surrounded by a ring of thickened 

 cniicle. CEsophagus divided into a short anterior and a long 

 posterior portion, both muscular, the latter ending in a well- 

 marked bulb, which is preceded by an oval swelling. Excre- 

 tory pore towards posterior end of oesophagus. Tail in both 

 sexes tajjering and pointed. Caudal end of male with ten 

 pairs of papillee and a median preanal papilla (double in 

 F. siamenais). A series of simple, iusiform, musculai-, preanal 

 sucker-like organs n)ay be })re.-ent. Spicules equal, sickle- 

 shaped, eaeh having the ajjpearance of a spicule within a 

 spicule. An accessory piece present. Vulva towards poste- 

 rior third of bod}'. Vagina runs forward and gives off two 

 opposed uteri, each of which doubles upon itself in a iiuml)er 

 of longitudinally-disposed U-shaped loops in the anterior or 

 posterior region of the body respectively. Ova huge, thick- 

 shelled, with contents only beginning to segment when laid. 



