Two species of the amphipod Bathyporeia Lindström, B. nana Toulmond and B. sarsi Watkin, have been collected from sand beaches in the Firth of Clyde, both of which appear to be new records for the Clyde Sea area. This may be the first definite record of B. sarsi from the west coast of Britain. In addition, B. nana has been collected from a beach near Oban, Argyll.

The rhabdocoele turbellarian Paravortex scrobiculariae (Graff) was first described, but not named, by Villot (1878) who discovered this parasite living in the gut of Abra tennis (Montagu) in Brittany. In naming the species, Graff (1882) did not add to Villot's description. Wahl (1906) erected the genus Paravortex to include this form which he had found in Scrobicularia plana (da Costa) and Venerupis decussata (L.) at Trieste and Naples. The first record of P. scrobiculariae in British waters was supplied by Freeman (1957) who, working at Whitstable, Kent, found 8 specimens in 3 out of a sample of 40 S. plana he examined. No further British record appears to have been made.

A recent survey has shown Paravortex to be common and widespread in S. plana inhabiting the estuaries of south-west England. As noted by previous workers, Paravortex can be readily seen through the semi-transparent gut wall of its host on account of its pinkish colour; observation is facilitated if the bivalve is maintained in clean sea water for 3–4 days to allow evacuation of some of the gut contents and is most easily performed during the winter months when gametes are not present in quantity. In this study, counts of the Paravortex were made by removing the gut from the surrounding foot tissues and releasing the Paravortex by cutting the gut longitudinally. From each locality, 20–30 S. plana, all within the length range of 30–50 mm, were examined. Paravortex is viviparous, the newly-hatched young being 120–150 μm long; at this stage they are transparent and are easily overlooked amongst the gut contents; thus counts relate chiefly to adults 0·5–1·5 mm in length.

Since 1973 the main groups of diatoms and dinoflagellates have been analysed in a monthly monitoring programme of phytoplankton in Dutch coastal waters. In 1974 a large, conspicuous diatom, Pleurosigma planctonicum Simonsen (Simonsen, 1974) occurred in small numbers with a denser population at two sampling sites where the salinity was greater than 33%. Details of the distribution are shown in Fig. 1.

Convoluta roscoffensis (Graff) has long been known for its symbiosis with a green flagellate definitively described from French stock as Platymonas convolutae by Parke and Manton (Parke & Manton, 1967). Provasoli subsequently discovered a species of Prasinocladus in a culture isolated from C. roscoffensis, but concluded that it was a surface contaminant of the animal (Provasoli, Yamasu & Manton, 1968).

Populations of C. roscoffensis from Aberthaw, South Wales (Mettam, 1979), and eighteen sites on Guernsey have been studied. In most patches of the Aberthaw colony, and in two of the Guernsey sites, two algal symbionts have been found. One of the Guernsey, and one of the Aberthaw symbionts appear identical to Platymonas convolutae.

They can be distinguished at the ultrastructural level by the presence of canaliculi which penetrate the pyrenoid, and are lined with the double-layered plastid envelope. In both cases the second flagellate shows the nucleus-pyrenoid complex typical of the genus Prasinocladus, where the nucleus penetrates the pyrenoid, and a pair of thylakoid membranes separate the pyrenoid from the starch shell (Parke & Manton, 1965). Neither symbiont has been identified specifically.

It is also possible to distinguish the two symbionts in the living animals, since the cup-shaped pyrenoid of the Prasinocladus type is easily distinguished from the spherical condition in Platymonas using the light microscope. A mixed population of symbionts has never been found in an individual worm. For each patch of animals in a colony it was possible to establish the percentage of animals containing each symbiont. This ratio varies from patch to patch in the colony, but has remained remarkably constant within each patch over the six months it has been studied. The Prasinocladus type always predominates at Aberthaw, the Platymonas type being absent in places.

During a recent preliminary survey of the Clyde deeps using a 0–5 m D-net (mesh ca. 1 mm, 26 mesh per inch), three little known species of Amphipoda were collected. Amphilochoides boecki Sars (Amphilochidae) was taken over a consolidated sand Dentalium ground inside Sgat Mhor, Ascog Bay, Lower L. Fyne on 3 July 1980 from a depth of 36 m. This species has been recognized as distinct from A. serratipes (Norman) by Lincoln (1979) who noted that no British material of A. boecki had been confirmed to date. This therefore represents the first British record of the species. Eriopisa elongata (Bruzelius) (Melitidae) was taken from 150 m between Cumbrae and Arran in the Clyde in 1885 by Canon A. M. Norman. Earlier (1866) dredgings with Gwyn Jeffreys in the Sound of Skye had first brought this species to light in British waters (Norman, 1889). I am not aware of any published record of E. elongata in the Clyde area since that time and it is not known from anywhere else in Britain (Lincoln, 1979). The species (two individuals) was taken in 118 m over a soft mud bottom off Holy Isle (Arran) on 3 July 1980. Dyopedos monacanthus (Metzger) (Podoceridae) has been taken once previously in the Clyde, from the stomach of a haddock in 1897 (Scott, 1901 as Dulichia monacantha Metzger), a record not included in Lincoln's (1979) latest review. Two individuals were captured on 2 July 1980, over soft mud, from 183 m off Tarbert, Lower L. Fyne.