ANGUILLULININAE 65 



B. Longitudinal fields eight. 



a. Cuticle without criss-cross fibres 



Hydromennie Corti, 1902. 



b. Cuticle with criss-cross fibres 



Eumermis Daday, 1911. 



On the whole, we are inclined to the view that all these 

 names should be regarded for the present as synonyms of 

 Mermis, together with several others not included in the key, 

 such as Autoplectus Balsamo-Crivelli, 1843, Spinifer v. Linstow, 

 1901 {Jena. Zeitschr., xxxv, 418), Tetradonema Cobb, 1919 

 {Journ. Parasitol., v, 185), Aproctonema Keilin, 1917 (Compt. 

 rend. Acad. Sci., Paris, clxv, 399), and Gastromermis Micoletsky, 

 1923 {Zool. Anz., Iv, 243). The last was proposed as a sub- 

 genus of Paramermis. Agamomermis Stiles, 1903, is not a generic 

 name, but a collective name for immature Mermithidae. 



Fam. 9. ANGUILLULINIDAE no v. 



Syn. Tylenchidae Micoletzky, 1922. 



Small, free-living, semi-parasitic or parasitic forms. Pharynx 

 in the adult modified into a protrusible stylet or " spear." 

 Oesophagus simple or with a median and a posterior bulb-like 

 swelling. When two swellings are present, only the anterior 

 of them is a muscular bulb. Caudal glands and spinneret 

 usually absent. 



Micoletzky (1922) divides the family Tylenchidae into three 

 subfamilies (Diphtherophorinae, Dorylaiminae and Tylen- 

 chinae), basing his classification chiefly upon the structure of 

 the stylet, which may be more or less evidently formed of three 

 separate rods, and may show more or less obvious traces of 

 three posterior knobs, one belonging to each of the rods. 

 This system does not, however, appear to offer a natural 

 classification of the group, and it seems to us that a somewhat 

 more satisfactory subdivision is arrived at by considering 

 primarily the characters of the oesophagus. There are two 

 main types of oesophageal structure in the family, and if the 

 genera be arranged in two groups according to the form of the 

 oesophagus, it is possible to regard these as two subfamilies 

 for which the comparatively well-known genera Anguillulina 

 and Dorylaimus may stand as types. 



Subfam. 1. ANGUILLULININAE no v. 

 Oesophagus with a median muscular bulb and a posterior 

 non-muscular swelling, the latter sometimes not distinctly 

 separated from the intestine. 



1. Anguillulina Gervais & van Beneden, 1859. 

 Syn. Anguina Scopoli, 1777 ; Tylelenchus Bastian, 1865 ; 

 Tylenchus Bastian, 1865 ; Eutylenchus Cobb, 1913 ; Atylenchus 



SYN. NEM. r 



