Immediately above this is a distinct belt of Xiphophora — beaches (Station 4) show a quite different zonation. On a peculiarly long and rather slender form which is either these platforms Hormosira banksii is very well developed a distinct species or an (marked) ecological variant. and Ulva lactuca is common. The pink basal structures Interrupting this brown belt in very, exposed places, as of Corallinas axe. abundant in more exposed places and on points and islets, are pure patches of the red algae, the erect calcareous thallus of this species frequently Pachymenia himantophora. dominates in the mtertidal pools. On shaded sides of the reefs Codium adhaerens is very common, while on exposed THE EAST COAST (STATION 2) rock faces (especially above the Xiphophora belt) Apophloea An interesting feature of the moderately exposed situations sinclairii is abundant. The oyster Saxostrea also occurs existing on the East Coast is the presence of Carpophyllum on these upper rocks of the supra-littoral fringe. Nerita maschalocarpum and C. elongatum growing together. The is conspicuous at the highest levels immediately in front C. elongatum dominates in the 'surge region' (lower-mid- of the narrow, moderately steep, shingle beach. littoral and upper infra-littoral fringe) whilst C. maschalo- carpum dominates below low tide mark in the infra- In conclusion it can be said that the zonation pattern littoral fringe proper. The presence of C. elongatum on of the Chickens appears to corrsepond closely with that the East Coast was at first puzzling, as this coastline is recognised so far by observers on other parts of the north• sheltered from the north by a low' reef and from the east east coastline of New Zealand. (See Trevarthen 1954 and by another island of the group. The C. elongatum belt Dellow 1955.) was largely explained when local boatmen pointed out that although the prevailing winds come from the south• References : west, the stronger gales come from the south-east, to which Dellow, V., 1955: 'Marine Algae Ecology of the Hauraki quarter this coastline is very exposed. Gulf, N.Z.' Trans Royal Soc. N.Z. Vol. 83 : 1, pp. 1-91. THE SOUTH COAST (STATION 3) Trevarthen, C. B., 1954: 'Features of Marine Ecology of On the headlands a' rather similar 'exposed coast' pattern Little Barrier, Mayor and Hen Islands.' Tane, Vol. 6, is developed, but the broad midlittoral platforms on the pp. 34-60. EARTHWORMS FROM WHAKAHAU AND MAROTIRI ISLANDS By MARGARET M. ESSON The earthworms, discussed below, collected in August found in the B horizon of grey brow'n crumbly clay. 1955, were kindly identified by Mr K. E. Lee of the S. gigantea was also found near the surface of the loose Soil Bureau. soil of the stream bed where surface litter was absent and where Metrosideros and Olea apetala were dominant. MAROTIRI ISLAND This species was also found near the Waipawa Stream of On Marotiri earthworms were predominantly large sub-soil Little Barrier in 1952. species of importance in the formation of soils. Those on Megascolides irregularis was found in the loose crumbly the Marotiri were found to be mainly of skeletal nature, clap topsoil of the upper and lower streams at stream or in the immature and semi-mature stages of develop• level under Metrosideros, Olea and Maeropiper and has ment. been found on Little Barrier near Waipawa Stream and Hoplochaetina subtiles, 5-6in. long, was found 9in. on Pohutukawa flat. deep, in the crumbly clay of the B horizon of the steep slopes in the vicinity of the petrel burrows, where surface Spenceriella shakespeari was commonly found in the litter was absent (spiders and insect larvae were present same habitat. It occurs widely on Little Barrier. in the soil). The vegetation included Metrosideros, Rhododrilus sp. was also found in this habitat. Mr Lee Leptospermum, Suttonia, Dysoxylum, Br achy glottis and notes that this may be R. sutherlandi which he described Asplenium. This species was not collected in 1952 on from Whangarei in Trans. Roy. Soc. Little Barrier or Mayor Islands. Spenceriella gigantea was found on the ridge 18in. deep WHAKAHAU in the flecked yellow brown crumbly clay of the C hori• A Megascolides sp. was collected by E. N. Milligan zon. Leptospermum was dominant; Suttonia, Pittosporum among litter under Metrosideros, Leptospermum, etc. Mr and Nothopanax were present and native grass and a Lee notes that these two small juvenile forms were deep mull litter covered the ground. No worms were probably M. maorica which was also collected on Little found in the litter, but smaller unidentified worms were Barrier in 1952. 15 AN ACCOUNT OF MERYTA SINCLAIRII (PUKANUI) ON MAROTIRI ISLAND By I. A. E. ATKINSON Though Meryta sinclairii with its enormous leaves and Because no counts of juvenile plants were made on the regularly shaped habit is well known as an ornamental coastal cliffs, the figure for the younger age groups is in plant in Auckland gardens, few people have had the all probability much too low. When allowance is made opportunity to see it growing in its native habitat. The for these facts it appears that regeneration of seedling Three Kings and Hen and Chickens island groups are and sapling stages has been, and still is, at least suffici• its only places of natural occurrence. ent to maintain the numbers of the adult plant. Evidence In what sort of situations does Meryta occur and is it will later be brought forward to show that the Meryta increasing, decreasing or merely maintaining its numbers population of Marotiri is actually increasing. on these islands? Is there any explanation for the pecu• liarly discontinuous distribution of this plant? These THE COASTAL CLIFF HABITAT: questions are discussed in the following account which Meryta is frequent, its bright green foliage standing out summarises observations made on Meryta during a clearly against the sombre green of pohutukawa (Metro• week's visit to Marotiri (Big Chicken Island) in August, sideros excelsa). Along the northern and eastern coasts 1955. For a full account of the island's vegetation refer• it usually occurs singly but no plants were observed ence should be made to the paper in this volume by around the cliffs of the north-western portion of the C. A. Percy. island. Stands or groves have been established at several points along the southern coast, the largest of which is DISTRIBUTION: situated at Koputotara Point and numbers approximately Meryta is present on all islands of the Chicken group and 120 plants. Since this grove is typical of the way in reaches its greatest abundance on Marotiri where three which Meryta occurs on the coast it is described more main types of habitat may be recognised: fully. 1. Ridge including the upper half of the valley wall. The site is a south-facing consolidated talus slide 2. Valley including the lower half of the valley wall. which falls steeply to the sea and is flanked on both sides 3. Coastal cliff including debris slides and rocky out• by vertical cliffs. Both these cliffs and the slopes behind crops. are dominated by pohutukawa, but on the talus slide Total counts of Meryta plants observed in each of there is complete dominance by Meryta. The closely these habitats are summarised in Table 1, while the spaced trees, up to 17 inches in diameter, form an actual distribution is indicated by the figures on the uneven closed canopy at a height of 25 feet, below accompanying map (See fig. 1). which there are only a few Astelia plants. Seedlings and TABLE. I saplings of Meryta are restricted to the perimeter of the Habitat No. of plants observed grove which is apparently even-aged. Coastal cliff 286 Buddie (1948) has described larger but otherwise simi• Valley 203 lar groves on South West and North East Islands of the Ridge 87 Three Kings group. On the coastal cliffs Meryta usually grows on unstable Total: 576 debris material rather than rocky outcrops; a preference On the sea-cliffs these figures are counts of adult which may be related to the structure of the root plants only, while inland they are totals of juvenile and system. All specimens examined had strongly developed adults counted along traverses of valley-bottoms and tap-roots as well as a system of superficial lateral roots. ridge-tops. Although a wide coverage of the island was A deeply penetrating tap root would be suitable for made, many plants will have been missed. Nevertheless colonisation of unstable talus material though possibly a the total Meryta population of the island would probably disadvantage in establishment on rock surfaces. not exceed 1,000 plants. Reference to the map should enable future observers to follow any major numerical THE RIDGE HABITAT: fluctuations which may take place. On the kanuka (Leptospermum ericoides) dominated ridges, Meryta plants, both juvenile and adult, are widely POPULATION ANALYSIS: scattered. Along the western ridges no plants were ob• Though varying according to environmental conditions, served but on other ridge-tops, fruiting adult plants heights may be taken as a reasonable index of age. were seen up to 480 feet above sea-level. Juvenile plants Using a camera range-finder, 378 plants were measured, were confined to areas of Leptospermum scrub in which which when classed into height groups give an indication other species, particularly kohe-kohe (Dysoxylum specta- of the age group distribution of the population (See bile) were regenerating. fig. 2). On the south-west ridge leading towards Koputotara 16 Point, there is a small group of ten Meryta trees, up to It can be seen that Meryta is well established in each 30 feet high, which with some seedlings and saplings, of the three main types of habitat on the island.