ON THE ANGUILLULID^. 129 



one elongated near its middle, and the other terminal, rounded, and containing a 

 simple valvular apparatus. Intestine rather sparsely covered with fat-particles, 

 the large containing cells of which can sometimes be recognized. Vulva near the 

 middle of body. Uterus bifid, segments symmetrical. Oviparous or viviparous. 

 Spicules of moderate size, slightly curved. Accessory piece single, posterior, me- 

 dian, about half as long. Caudal alee lateral, membranous, supported by sets of 

 rays. Ventral gland wanting. Lateral vessels or cellular canals not seen. 

 Movements active. 

 Although I have looked very carefully for them, I have been unable to distinguish 



either lateral vessels or the ventral excretory gland in any of the representatives of this 



genus. 



The typical Rhabdltis terricola of Dujardin seems undoubtedly to correspond as re- 

 gards structural details with the other species that I have placed in this genus ; and, 

 since it is now evident that Dujardin associated with this animal others of such diverse 

 types as Anguillula aceti and Tylelenchus tritici, we shall have the less difficulty in 

 imagining that he may have confounded with them also members of the genus Flectus, 

 not only because they seem to be much more abundant than are the proper representa- 

 tives of the genus Rhabdltis, but also because he speaks of the latter as possessing that 

 remarkable tenacity of life which belongs to species of the two former genera, when, 

 as far as my experience goes, it is not possessed by the real allies of the typical Bhab- 

 ditis terricola. 



1. R. MARINA, n. sp. (Plate X. figs. 60-62.) 



Female, length ^", breadth itIt"- 



External Characters. — Body tapering considerably anteriorly, but more posteriorly, 

 where it narrows to a point. Head truncate, naked. Integument having transverse 

 and longitudinal strice, those of each set being about toooo" apart. 



Pharyngeal cavity cylindrical, xrrr" long. (Esophagus ^th of total length, containing 

 in its terminal enlargement a valvular apparatus, which may be seen to open and shut with 

 spring-like rapidity for the passage of fluids. Posterior part of oesophagus and anterior 

 portion of intestine fixed to parietes by distinct muscular retinacula. Intestine much 

 larger at commencement than terminal part of oesophagus ; covered sparsely with fat- 

 particles, the containing cells of which can occasionally be recognized. Anus ybf" from 

 posterior extremity. Vidoa slightly posterior to middle of body. Vterus bifid; seg- 

 ments symmetrical, large, and densely distended with freely moving young and ova in 

 all stages of development. Ova 4^" long, by -^" broad. Gland-system very slightly 

 developed ; but numerous floating gland- or blood-cells in cavity of body, the maximum 

 size being about y^g-g-" in diameter". 



Male, length ^", breadth ^go "• 



Anus aiy" from posterior extremity. Genital tube consisting of a single testicle, 



' I have observed (in the female only) what appear to be two lateral apertures through the integument, connected 

 ■with an obscure appearance of oval vesicles or dilatations internally, situated exactly midway between the anus and 

 posterior extremity. 



VOL. XXV. 8 



