DESMOSCOLECIDAE 107 



3. Prochaetosoma nom. nov. 



Syn. Rhabdogaster Metchnikoff, 1867, nee Loew, 1858. 



Cephalic region not swollen, passing gradually into body. 

 Body stouter in posterior half. Head without papillae. 

 Oesophagus cylindrical, with well-developed posterior bulb, 

 and sometimes an anterior swelling. Ventral appendages 

 in two submedian rows, solid, somewhat hooked, extending 

 in front of vulva, or entirely in front of it, in female. Male 

 without accessory piece. A single large caudal gland present. 



Hab. Marine. 



Genotjrpe : P. [Rhabdogaster] cygnoides (Metchnikoff, 1867). 



Metchnikoff, 1867, Zeitschr.f. wiss. Zool., xvii, 542 ; Steiner, 

 1916, Zool. Jahrb., Syst., xxxix, 574; Stauffer, 1924, Zool. 

 Jahrb., Syst., xlix, 119. 



4. Notochaetosoma Irwin-Smith, 1918. 



Cephalic region not swollen. Oesophagus cylindrical, faintly 

 swollen behind. Ventral appendages in four rows, mostly 

 jointed near the tip, confined to postvulvar region. An 

 accessory piece present. A single caudal gland present. 



Hab. Marine. 



Genotjrpe : N. tenax Irwin-Smith, 1918. 



Irwin-Smith, 1918, Proc. Linn. Soc. N.8.W., Sydney, xlii, 

 798. 



Fam. 13. DESMOSCOLECIDAE Southern, 1914. 



(Desmoscoleciden Schepotieff, 1908). 



Stout, spindle-shaped, free-living forms. Body and tail 

 either with opaque transverse rings, or with numerous trans- 

 verse rings or longitudinal rows of bristles. Head usually 

 distinct, more or less rounded. Lateral organs present. 

 Mouth circular or transversely elongate. Pharynx narrow, 

 with thick cuticular lining. Oesophagus usually somewhat 

 swollen behind. Male with two spicules and one or two 

 accessory pieces. Testis single, reflexed. Female genital 

 tubes paired, opposed. Eggs large and few, sometimes 

 carried attached to the body of the parent. 



1. Desmoscolex Claparede, 1863. 



Syn. Quadricoma Filipjev, 1922. 



Body and tail with opaque transverse rings, formed by a 

 secretion to which foreign particles become cemented, and 

 with more or less pronounced clear interspaces. A few 

 bristles present on the body, sometimes jointed and usually 

 arranged in pairs. 



