ON THE ANGUILLULID X. 97 
LAND AND FRESHWATER’. 
1. MONHYSTERA?, Bastian. 
Gex. CHAR. Body mostly tapering considerably posteriorly. Caudal sucker small, some- 
what pointed. Jntegument unstriated; sete very few; lateral circular mark on 
either side near anterior extremity. Pharyngeal cavity none. (Esophagus uniform, 
cylindrical. Intestinal cells not tessellated. Vulva about posterior third of body. 
Uterus unsymmetrical. Viviparous or oviparous. Spicules long and narrow. Ac- 
cessory piece, when present, single, small. Ocellus single, often absent. 
In all probability, the two species which I have named M. disjuncta and M. ambigua 
will hereafter be found to belong to a distinct genus; but, not having seen the females of 
either, I was unwilling to describe them apart, and have therefore placed them tem- 
porarily in that genus to which they seemed to be the most nearly allied. 
1, M. sTAGNALIS, n. = (Plate wee figs. 9-11.) 
Female, length 715”, breadth 415". 
External Characters.—Body opaque-white in part, tapering considerably at extremities, 
especially towards the posterior, which is long and filiform. Head truncated, having a 
cirelet of 4-6 short setæ. Integument plain. 
(Esophagus about ith of whole length. Intestine narrowed where encroached upon by 
genital tube, but widening considerably behind vulva. Anus 414" from posterior ex- 
tremity. Vulva behind commencement of posterior third of body. Viviparous; young 
numerous. Ocellus bright red, on sheath of cesophagus. 
Male, length 33”, breadth 444”. Anus 715” from posterior extremity. Spicules sgo” 
long. Accessory piece small, somewhat triangular. Spermatozoa having slight vibra- 
tile movements, of an elongated oval form, oyo” long. 
Hab. Mud from ponds, Falmouth and Easthampstead. 
2. M. DISPAR, n. T (Plate IX. ne 1/2.) 
Female, sis. 
External Cintas —Body scarcely tapering at all anteriorly, but abruptly behind 
vulva, and then gradually narrowing so as to terminate with a filiform extremity and 
minute pointed sucker. Te iruncate, provided with 2-4 short setæ. Integument 
hyaline. 
Gisophagus 1th of total length. Intestinal cells containing rather large dark-coloured 
particles, having indistinetly tessellated arrangement. Anus rn f from posterior ex- 
tremity. Vulva about commencement of posterior third of body. 
Male, not seen. 
Hab. In moss, Falmouth. 
3. M. RIVULARIS, n. Sp. Fee m figs. 3, 4.) 
Male, length 2;”, breadth $$$ ^ 
* Three exceptions to this, — RAabditis marina, — — and M. disjuncta being marine, and found 
amongst the sand of tide. -pools. 2 uóvos, single, and vorepa, the uterus. 
VOL, XXV. i 0 
