B. END VIEW OF THE STATION WITH SPAWNING POND IN FOREGROUND. MARINE BIOLOGICAL STATION AT PORT ERIN.

against the wall of the building and there is no gallery for access to them from the rear. They are reached only through doors above the plate-glass fronts opening directly from the aquarium room, an arrangement which seriously interferes with lighting and the care of the tanks. A door to the left leads into the laboratory wing (28 by 32 feet), which contains a main laboratory (15 by 30 feet), from which open a storeroom (7 by 12 feet), a dark room (4 by 12 feet), a library (10 by 12 feet), a workroom (6 by 12 feet), and a passage (3 by 12 feet) to the rear of the building. The main laboratory contains six cubicals (each 5 by 10 feet), separated by partitions 7 feet in height, each fitted with a shelf table fronting the single window, sink with salt and fresh-water supply, and abundant shelving. The room is heated by an open grate at the end.

The west wing (37 by 40 feet) contains the hatchery (27 by 30 feet), with eight Dannevig fish-hatching tanks (Pl. XXXV, B) along the wall, operated by a Scott-Johnstone tip bucket. (For a complete description of these see Herdman, 1909, and figs. 21-27.) A concrete storage tank or floor aquarium 9 feet 8 inches long, 5 feet 6 inches

FIG. 21.-Elevation of filter, Scott-Johnstone tipping-box, hatching tanks, and oscillating apparatus.

wide, and 3 feet deep, and walls 17 inches thick is placed in one corner. A passage leads to the storeroom (5 by 6 feet), engine room (9 by 27 feet), and to the rear yard, and a door to the west leads directly to the hatchery pond.

The upper floor of the building is reached by a spiral iron staircase, which ascends from the northeast corner of the aquarium hall to the spacious gallery lighted from above and by north and east windows. The balustrade supports a series of desk cases for the exhibition of museum specimens, while around the walls are cupboards and cases for herbarium and museum collections. Against the balustrade stands a fine bust of Edward Forbes, the pioneer explorer of the Irish Sea. The large room in the east wing (30 by 32 feet) is fitted up as a lecture room and elementary laboratory, and the corresponding room in the west wing serves as a storeroom for nets and tackle.

Within the walled area to the west of the building a spawning pond (50 by 90 feet) (Pl. XXXV, B) with a depth of 2 to 9 feet has been excavated in the solid rock. Its capacity is 150,000 gallons. It is

45504°-Bull. 4-10-13

divided into two parts by a cross wall with a regulated sluiceway, and is used for the confinement of the spawning plaice.

The water supply of the station is drawn from the harbor through a 4-inch east-iron pipe, 270 feet in length, carried to a clean rock on the beach below half-tide mark, where it ends in a perforated wooden rose box. The pump is of three-plunger vertical type capable of delivering 4,000 gallons per hour and is run by a 3-horsepower Crossley gas engine. The water is pumped into two irregular reservoirs with masonry walls faced with concrete. The upper cistern, with its floor 33 feet above the sea and 12 feet above the laboratory

FIG. 22.-Ground plan of hatchery and tank. Same scale as fig. 21.

floor, has a capacity of 11,000 gallons, and the lower (with its floor 5 feet below that of the upper cistern) of 16,000 gallons. Three-inch galvanized-iron pipes conduct the water to and from the cisterns, and galvanized piping is used throughout the distributing system. This was thoroughly galvanized after fitting and has stood since construction without visible trouble from rust. The valves and the cocks are of brass, but as few as possible are used in the system. The terminals are cocks of brass connected with Sprengel tubes of rubber hose and glass (fig. 21) and are used to deliver a mixture of water and

air through glass tubes to a depth 1 foot above the bottom of the aquarium. Overhead jets are for the smaller used open aquaria.

The aquaria at Port Erin are among the most thriving in European stations. The purity of the water and the care taken with the piping and the stocking of the aquaria are such that animals live for years in the aquaria without disaster. The fish are fed daily on raw mussels, herring (chopped fine), and the anemones weekly upon crabs or

fish. The display of anemones in the open wooden aquaria is noteworthy for its variety and beauty. The walls of the cement aquaria are covered by normal growths in situ of hydroids, bryozoans, worm tubes, and sponges, incrusting forms of the latter forming beautiful circular colonies nearly 2 feet in diameter. Even a few small seaweeds have grown in the tanks, but the metal used in the valves is probably

FEET

FIG. 24.-Hatching tank (DHT, fig. 21), seen from above.

inimical to their continued growth. Considerable trouble has been caused by the growth of organisms in the pipes also.

The equipment of the Port Erin station is simple and inexpensive,

in so far as the chemicals and glassware are concerned. There are eleven microscopes, one large Ross, and ten Beck student stands, three dissecting microscopes, incubator, and rocking and sliding microtomes.

The marine equipment is most excellent and is kept in prime order. The station has the use to some extent of a private steam yacht, The Ladybird. She is a schooner-rigged steamer of 36 tons yacht measurement, 69 feet in length, 11 feet 8 inches beam, 6 feet draft, with engine of 55 horsepower and a speed of 9 knots per hour. She carries a crew of three men and is fitted with a steam capstan and about 100 fathoms of dredging cable. Row and sail boats for harbor