TRANSACTIONS OF THE SECTIONS. 195 
white spherical glassy bodies were perceived sticking amongst the florets, and closely 
invested by them. On extracting one of these, it was found to be a soft turgid~ 
animal, evidently an Acarus, but differing from most species of this genus, in being 
to outward appearance destitute of legs. This creature is about half a line in length. 
The author then proceeded to give a detailed account of its structure. Although in 
the later stages of its growth no legs are perceptible, the author had abundant oppor- 
tunities of observing the young immediately after being hatched, when they were 
found to possess six very serviceable legs. The dcari are most abundant near the 
summit of the panicle, but they sometimes occupy the base only. The stem of the 
grass seems the principal object of their attack, and the drooping of the panicle the 
result of the arrest of the ascending sap, which they use for their own nourishment. 
The author had also observed this creature on Holcus mollis, or likewise Avia cespt- 
tosa and Phalaris arundinacea. He proposed to call the species Acarus graminisugus. 
The author had also observed a new Vibrio. This was noticed on the sheep’s Fescue 
grass (Festuca ovina), and some other grasses of the sea-caast. They are affected 
with several purple knots or swellings, which on being opened appear as if filled 
with bluish or purplish granules ; but on closer examination, a little white annelide 
was observed coiled up, inchannels winding amongst the granules. These were the 
Vibriones. Some of the knots contained only one, others half-a-dozen of these 
creatures. They are white, almost transparent, very minute, just visible to the eye, 
and slender-pointed at each end. This Vibrio differs from the one described by 
Mr. Bauer, and which produces the ear-cockles or bunt in wheat. The author there- ‘ 
fore proposes to call this species Vibrio graminis. It is by no means unfrequent 
amongst the short grasses on the sea-coast, and occurs likewise inland, especially on 
Agrostis alba. 
On the Genus Perodictieus of Bennett, and its relation to Stenops. 
By Prof. Van per Hoeven. 
The Lemur Pollo of Gmelin, a species from the coast of Guinea, had hitherto only 
been known very imperfectly, the two specimens observed by the late Mr. Bennett 
and by the author of this notice having been both young and not having all their 
teeth. The author has had the opportunity of examining an adult specimen in the 
past year, and found the dentition quite similar to that of the genus Stenops. The 
tarsal bones were of the same shape as in Stenops, and the statement of Bennett, that 
the tarsus was elongated, is incorrect. Tt seems then that Perodicticus, the genus 
formed by Bennett on the Lemur Pollo, is not sufficiently distinct fiom Stenops, and 
could only be admitted as a subgeneric group, by those who are not willing to admit 
the fashion of many contemporary authors, who make genera for nearly every species. 
The tail and the short index of Perodicticus seem to be characters of an inferior 
and subordinate order. 
On the Upper Jaw of the Iguanodon. By G. A. ManTELL, LL.D., F.RS. 
Dr. Mantell exhibited and described a portion of the upper jaw, with seven teeth 
in place, of the Iguanodon, recently discovered in the Wealden of Sussex. Dr. M. 
laid before the Section specimens of the upper and lower teeth of this gigantic her- 
bivorous reptile of various ages, and in different states of detrition from use, and 
explained the dental arrangement Dr. Melville and himself had inferred from the 
detached teeth, and which was confirmed by the fossil now exhibited, in which there 
were several mature molars in their natural position. Drawings and restored figures 
of the cranium and jaws were shown in illustration of the author’s remarks ; and the 
opinions of the comparative anatomists present were solicited as to the physiological 
inferences to be deduced from the anatomical facts described ; especially relating to 
the muscles, prehensile tongue, and flexible lips, as indicated by the edentate cha- 
racter of the symphysial portion of the lower jaw, and the number and magnitude 
of the vascular foramina, &c., characters not present in any existing type of the class 
Reptilia. 
