Thelazia ugandensis n.sp. is described from a hooded vulture. It differs from the other known species in the length of the spicules, length of the gubernaculum and the number and position of male caudal papillae.

Seven specimens of this new species were collected from the intestine of a freshwater turtle, Trionyx triungnis (═T. nilotica) in the Sudan.

These are lanceolate worms which gradually taper to rounded ends, with a length of 2⋅5–2⋅9 mm. and a width of 0⋅6–0⋅9 mm. The cuticle is invested with scales, dense in the anterior half of the worm, but becoming more and more sparse towards the caudal end. The oral sucker is large, measuring 0⋅23–0⋅27 mm. in diameter and is about one and a half times the diameter of the ventral sucker which measures 0⋅14–0⋅17 mm. in diameter. Both suckers lie in the anterior half of the body. The mouth is subterminal and leads to a pharynx which is stout, 0⋅7–0⋅8 mm. by 0⋅11–0⋅12 mm., and leads to a long oesophagus of 0⋅25–0⋅32 mm. in length. The caeca terminate at the posterior border of the posterior testis or slightly anterior to it.

1. A new species of the genus Ptychobothrium Loennberg 1889, recovered from the intestine of the Hying fish Cypselttrus poecthpterus Cuv. and Val., off the coast of Waltair, is described.

2. Ptychobothrium cypseluri n.sp. differs from P. bclottes (Dujardin, 1845), the only other known species of the genus, in the nature of the ovary, uterus and the number of testes.

Four worms were recovered from the intestine of a Scaly Anteater, Manis temminckii, examined in this Department in August, 1958. They appear to represent a new species for which I propose the name Inermicapsifer rhodesiensis.

Eleven cestode specimens were collected from the intestine of Prinops plumata which was brought into the Department for examination. They appear to be a new species for which the name Anomotaenia prinopsia is given.

The seasonal availability of sheep nematode infective larvae under normal farm conditions was investigated by exposing lambs reared worm free for two weekly periods in the fields. Data were collected in the form of populations found at post mortem examination.

It was found that Nematodirus spp. were acquired in greatest numbers in the autumn after the date by which lambs normally have acquired resistance to superinfection. The conclusion was that self-augmentation of Nematodirus parasitism in lambs resulting from eggs the lambs conveyed to the ground was of minor significance and that eggs reaching the ground in one season are the source of parasitism in lambs in the following spring.

It was found that greatest numbers of Haemonchus conlortus were acquired in summer. Heavy contamination of pasture with eggs of this species by ewes in the spring did not result in large populations in their lambs. It was concluded that the extent of parasitism in lambs in the late summer and autumn was contingent on there being favourable conditions at that time of the year for the development of infective larvae.

Previously uninfected eleven month old sheep were used as indicators of the availability of the infective larvae of sheep nematodes in early spring. Ostertagia and Nematodirus species were acquired in much larger numbers than other species. It is concluded, since the order of parasitism found in the experimental sheep resembled that found in spring born flock lambs in early life, that the relative specific incidence is the latter is due to the numbers of available infective larvae and not to any factor associated with the stage of development of the lambs.

Sheep reared worm free were used as indicators of the availability of sheep nematode infective larvae during the summer on pasture grazed by ordinary flock ewes and their lambs.

Data were collected in terms of worms found in the test sheep at post mortem examination after periods of three weeks' exposure in the field.

Haemonchus contortus infective larvae were given to previously uninfected weaned and unweaned romney lambs. Difference in susceptibility between the groups was not found.

Page 221 Legend to figure should read “Fig”5.

Page 223 Legend to figure should read “Fig. 3”.

Page 272 for “Morgascarida” read “Morgascaridia”.