ON THE ANGUILLULID/E. 101 



this type, whilst I have transferred the freshwater memhers to my new genus Ilonon- 

 clms. The species of this latter genus differ from those of the former in having one 

 pharyngeal hook only instead of three ; in having the head sometimes furnished with 

 papillce, but never, as far as I have seen, with seta? ; by the different structure of the 

 oesophagus, and absence of the peculiar oesophageal ring ; and, lastly, by the compara- 

 tively undeveloped condition of the caudal sucker and its appendages. 



The males of this genus must be either very minute or very scarce ; for though I 

 have seen nearly one hundred female representatives of the different species, I have 

 never met with a single specimen of the opposite sex. 



1. M. TRTJNCATUS, n. sp. (Plate IX. figs. 25, 26.) 

 Female, length -j^", breadth -^". 



External Characlers.—Bodj tapering slightly anteriorly, but more considerably pos- 

 teriorly. Head truncate ; no papillce. Integument with longitudinal strife, tmuj" apart. 



Fliarrjngeal cavity oval, -^^" in length, with a single hook projecting from upper 

 surface. (Esophagus about ^th of total length. Intestinal cells with light-coloured 

 particles, having distinctly tessellated arrangement. Anus -j^^" from posterior extre- 

 mity. Vulva slightly posterior to middle of body. Lateral canals broad, very indis- 

 tinct, only recognizable behind intestine ; no cells apparent — merely a few light-coloured 

 scattered granules. 



Male, not seen. 



Kah. Small pool amidst decaying moss and liverwort, Talmouth. 



2. M. PAPiLLATUS, n. sp. (Plate IX. figs. 27, 28.) 

 'Female, length ^r", breadth 2-50''" 



External Characters.— Bodij opaque-white in colour, tapering slightly anteriorly, but 

 gradually to a point posteriorly. Head truncate; mouth surrounded by four weU- 

 marked papillae. Integument Avitli longitudinal strise, about jTrkro" apart. 



Fharyngeal cavity a little removed from anterior extremity, proportionally rather 

 small, Y^" long ; tooth single. (Esophagus \i.h of total length. Intestinal cells con- 

 taining yellowish-coloured granules. Anus yb^" from posterior extremity. Vulva at 

 commencement of posterior third of body. Uterus bifid. 



Male, not seen. 



Sab. Between the sheaths of the leaves, at the lower part of culm of Festuca elatior, 

 Broadmoor, Berks. 



3. M. MACROSTOMA, n. sp. (Plate IX. figs. 29, 30.) 

 Female, length -j^", breadth -j^x". 



External Characters.—Bodj tapering very slightly towards head, more considerably 

 posteriorly, where it is filiform for a short distance. Head obtusely rounded, with two 

 papillfE, upper and lower. Integument with longitudinal strise. 



Fharyngeal cavity large, ^" long ; hook single, rmxj" ^ong. (Esophagus about ^th 

 of total length; very slightly increased in size posteriorly, where also there is a di- 



