1889. ] Mr 8. F. Harmer, On a species of Dinophilus. 359 
changes occurring in their transverse diameter were noted. The 
chief result of interest is that in most cases (e.g. Helianthus 
annuus) the diameter increases at first and subsequently dimi- 
nishes. In the case of Impatiens sultant the imcrease is not 
followed by any diminution in thickness. The results are of 
interest as showing the different extensibility of cell-walls in 
different directions. 
(2) On the thickening of the stem in varrous species of Thun- 
bergia. By M. C. Porrer, M.A., Peterhouse, and W. GARDINER, 
M.A., Clare College. 
The stems of various species of Thunbergia are considerably 
thickened just above the insertion of the leaves, these thickenings 
possessing a structure resembling that of the pulvinus of Mamosa; 
just as the leaves of this plant are raised or lowered by their 
pulvini, so the stems of Thunbergia are capable of motion at the 
nodes. The authors called attention to the climbing habits of 
the species of Thunbergia, and to the advantages gained by pos- 
sessing stem-pulvini. 
The observations were made simultaneously by Mr Potter on 
T. laurifolia in Ceylon, and by Mr Gardiner on 7. natalensis in 
Cambridge. 
(8) On a new species of Dinophilus. By 8. F. Harmer, M.A., 
King’s College. 
This species of Dinophilus was found at Plymouth, in rock- 
pools not far below high-water mark, in March and April of the 
present year. The maximum length is about 2 mm., and the 
male and female do not differ from one another in size or in 
external appearance. The head bears two prae-oral rings of cilia, 
but has no ciliated pits; the body consists of five segments 
(specially distinct in young individuals) and a tail, and is covered 
ventrally by a uniform coating of cilia. The dorsal and lateral 
portions of each segment are encircled by two ciliated rings, as in 
Protodrilus Leuckartu, described by Hatschek. In preserved 
specimens, the two ciliated rings of each segment give rise to the 
appearance of a broad band encircling the middle region of the 
segment, and in allusion to this character the name D. taeniatus 
was suggested for the species. An eleventh post-oral ciliated ring 
occurs immediately in front of the anus. 
Five pairs of nephridia were described in the female; in the 
male, the fifth nephridium of each side is converted into a large 
vesicula seminalis, into which ripe spermatozoa are received by 
means of a ciliated funnel. Each vesicula seminalis opens by a 
short duct into a median penis, which has an external aperture 
on the ventral side, nearly opposite the anus. Fertilization is 
