80 ASCAROIDEA 



of teeth, in its wall. Oesophagus cylindrical, with indistinct 

 pyriform bulb. Caudal end of male without supplementary 

 organs, bristles or papillae. An accessory piece, without 

 posterior process, present. Testis single, anterior, out- 

 stretched. Female genital tubes paired, opposed, reflexed. 

 Caudal glands and spinneret present. 



Hab. Marine. 



Genotype : P. rotundicephalus Cobb, 1920. 



Cobb, 1920, Contr. Sci. Nematol., ix, 273 and key. 



12. Monhystera Bastian, 1865. 



Syn.* Monohystera de Man, et auctt. ; Tachyhodites Bastian 

 1865 ; Theristus Bastian, 1865 ; Penzancia de Man, 1889 

 Austronema Cobb, 1914; Paramonohystera Steiner, 1916 

 Steineria Micoletzky, 1922, nee Filipjev, 1922 ; Allomonhystera 

 Micoletzky, 1923. 



Cuticle smooth or striated, usually with bristles, irregularly 

 distribvited or in submedian rows. Lateral alae absent. 

 Head generally with indistinct lijjs, almost always with bristles. 

 Lateral organs usually circular. Buccal capsule very small, 

 thin-walled, saucer- or cup-shaped, its walls continuous with 

 the oesophageal lining, which is fumiel-shaped anteriorly. 

 Oesophagus cylindrical, usually slightly expanded posteriorly, 

 without distinct bulb. Ocelli sometimes present in aquatic 

 forms. Two equal spicules and usually an accessory piece 

 present, the latter commonly with a posterior process. Testis 

 generally single. Female genital tube usually single, anterior, 

 outstretched. Mostly oviparous. Caudal glands and spin- 

 neret usually present. Parthenogenesis common in non- 

 marine forms. 



Hab. Aquatic (marine and fresh-water) ; also terricolous. 

 Genotyi^e : M. stagnalis Bastian, 1865 {fide Stiles & Hassall, 

 1905). 



Bastian, 1865, Trans. Linn. Soc. London, xxv, 93, 97 ; de 

 Man, 1884, Z)('e//-e(' . . . lebendenNematodend.Niederl. Fauna, 

 35; Micoletzky, 1922, Arch. f. Naturg., Abt. A, Ixxxvii, 165. 



13. Daptonema Cobb, 1920. 



Cuticle thick, rather coarsely striated. Scattered bristles 

 present in cervical region. Head rounded, not distinct, with 



* We have included as synonyms a number of names which have 

 been variously regarded by different authors as genera or as subgenera 

 of Monhystera. The available diagnoses of these forms are not 

 mutually exclusive, and do not appear to us sufficient to separate them 

 from Monhystera or from each other. Allomonhystera differs from the 

 other forms in having three preanal papillae in the male, but is other- 

 wise indistinguishable. 



