101 MR. H. CHARLTON BASTIAN'S MONOGRAPH 



near commencement. CEsophagus cylindrical, canal indicated by three briglit lines ; 

 transverse muscular fibres not distinct. Intestine moderately well covered ^yitll 

 hepatic cells containing light -colovired fat-particles indistinctly aggregated. Vulva 



about the middle of the body. Uterus bifid, segments symmetrical. Spicules ? 



Lateral canals ? Movements very sluggish. 



I. iGNAVUS, n. sp. (PI. IX. figs. 34 a, 34 b.) 



Female^ length xs", breadth y^". 



External Characters. — Body long and slender, tapering very gradually at both extre- 

 mities, tiU, at the posterior, it terminates in a long filiform portion. Head bluntly 

 rounded, provided with a circle of four very short setae. Integument having almost 

 imperceptible longitudinal striie, about 300IT0" apart. 



Fharijngeal cacitij long and narroAV, having three small, rounded, valve-lUve plates 

 near commencement. CEsophagus ^th of total length. Intestinal cells containing light- 

 coloured, non-tessellated particles. Anus x^" from posterior extremity. Vulm slightly 

 anterior to the middle of body. 



Male, not seen. 



Rab. Stagnant Avater of Easthampstead Plain, amongst Diatomacea^ and decaying 

 Algae ; also about the decaying submerged leaves of a species of Myrlophyllum from the 

 lake, Sandhurst. 



5. DOPvYLAIMUS, Dujardin. 



Urolahes, Carter; Anr/uilhila, Grube. 



Gen. Char. Sody sometimes blunt and rounded, sometimes filiform posteriorly. Caudal 

 sucker absent. Integument .haxing lougitudinal markings, more or less visible, and 

 a series of minute pores on each side of body ; seta; none ; cephalic papillae present 

 or absent. Fharynx indistinct, but somewhat cup-shaped, having a long, horny 

 and hollow exsertile spear projecting into and through it, which is renewed twice or 

 oftener during the period of growth. CEsophagtis having the posterior half, or one- 

 third, of increased size ; canal indicated by three bright lines ; transverse muscular 

 fibres not distinct. Intestine mostly well covered with hepatic cells containing fat- 

 particles having a tessellated arrangement. Vulva about the middle of body. Uterus 

 bifid, segments symmetrical. Spicules solitary, glaive-shaped ; males having some- 

 times a variable number of linear ventral suckers in mid line above anal cleft, and 

 also oblique markings of the integument. Lateral canals well developed and dis- 

 tinctly cellular. 

 The Nematoid {D. stagnalis) found by Dujardin at Rennes, within the stomachs of 

 certain fish, appears to me identical with tliat form which I have met with so abundantly 

 in mud from the bottom of freshwater ponds. Dujardin also appears to have found a 

 marine representative of this genus, though I have searched for such in vain. Curiously 

 enough, the form which Carter has taken as typical of his provisional genus Urolabes is 

 undoubtedly a member of the genus Dori/laimus ; and, from the absence of the caudal 

 sucker amongst these, its habits would probably not be of the nature indicated by 



