The aquaria in the laboratories are only glass containers placed as desired, in aquarium racks (Pl. XLIV, A) not unlike those of the Rovigno station. Shallow galvanized iron pans coated with a mixture of coal tar and ship's pitch and dried in heat are used as shelves. An upper shelf (30 by 80 cm.) is placed at a height of 1.5 m. and a lower one (50 by 80 cm.) at a height of 80 cm. The shelves are carried on a simple rack of slat-work and are supplied with salt water and compressed air. The overflow from the aquaria is caught in the pans and carried off by a waste pipe.

The aquaria in the basement are of reenforced concrete, of simple construction, built in situ. There are two large aquaria (fig. 40),

FIG. 44.-Third floor, zoological station at Trieste. Courtesy of Professor Cori.

containing about 0.4 cu. m. A cement table (85 by 165 cm. and 10 cm. thick) rests upon two cement pillars (20 by 75 and 100 cm. high). The cement frame, 78 cm. wide, 156 cm. long, and 60 cm. high, is glazed on four sides with openings on the ends 48 by 58 cm. and on the sides 48 by 124 cm. The walls are 12 cm. in thickness throughout and contain reenforcing metal only in the long horizontal stretches. The lower lintel is 4 cm. wide, the upper 8 cm., the vertical ones on the sides 16 cm., and those on the ends 10 cm. The plate glass, 15 mm. thick, is set in an aquarium cement, made as follows: Dry whiting with boiled linseed oil or linseed varnish is beaten into a thin

putty with a wooden hammer and then thickened to the proper consistency with red lead. No water is used, as in putty, and the materials are very thoroughly mixed by long-continued use of the hammer.

There is also a set of fifteen small connected cement aquaria (fig. 41,a,, figs. 45, 46, and 47, Pl. XLVI, B) of similar construction, each 96 cm. long, 68 cm. wide, and 60 cm. deep with side walls 10 cm. thick and partition walls 12 cm. They are glazed on two sides, the openings being 72 by 60 cm. and the glass 10 mm. in thickness. They stand on a cement table 1.1 m. high with cement supports (C) 1 by 0.68 by 0.10 m. and top (B) 75 cm. wide and 10 cm. thick, with trough of wood or cement along one side (fig. 46).

The water supply is delivered by an overhead jet entering a vertical canal, 4.5 cm. in diameter, in the end (A) and partition (E) wall which opens laterally at the bottom into the aquarium. A channel in the cement wall (0, fig. 47) adjacent to this receives the glass terminal of the compressed air pipe for aeration. The descending water in the outlet carries with it considerable air, supplying sufficient aeration in most cases. The outlet, as shown in the accompanying sketch (L', L'", L'", fig. 46), is a canal 22 cm. in diameter in the wall of the aquarium rising (L') from near the bottom to a cross pipe or channel near the top, thence downward (L') in the wall to the discharge (P). The water is thus maintained at a constant level, is drawn off from the bottom, and the vertical pipes can be easily cleaned when clogged through the orifices at M. The water enters the siphon through a series of small inlets in the cross pipe L'. In the series of small aquaria the outflow pipes are placed in the partition walls between adjacent aquaria. By closing the descender-pipe the water from the riser-pipe may be passed into the next aquarium at Q. It is possible thus to have individual or serial circulation in the tanks. The partition walls are a few centimeters lower than the others (see G, G', and E, fig. 45), so that in case of stoppage of outflow pipes of any tank the water merely overflows into the neighboring tanks, over the overflow ledge H (fig. 46). This type of aquarium very simply and effectively solves the difficulties of circulation, stoppage, and overflow.

There are also four large floor tanks (fig. 41, A1) of cement used as aquaria for large animals. The largest one, 1.2 by 1.5 m. and 1 meter in depth, has walls 12 cm. in thickness. Wooden tanks (A) 1.45 by 1.6 m. and 0.4 m. deep, with walls 3 cm. thick pitched inside and out, serve a similar purpose. Numerous small aquaria (A2) upon the window ledges and an out-of-door basin (2.5 by 2.5 and 0.35 m. deep) with glass cover beneath a glass canopy complete the extensive aquarium equipment of this station.

The station has an ample equipment of chemicals and glassware, microtomes, paraffin baths, etc., for biological work, a limited amount

FIG. 45.---Cement aquaria in Trieste station; vertical longitudinal section through end and first intermediate tank.

of physiological and chemical apparatus for work along special lines, an excellent biological library of over 4,000 volumes containing sets

and current numbers of about 25 leading periodicals and over 2,000 bound monographs and reprints, the more important general works and the reports of the Challenger, Valdivia, Plankton, and other expeditions. A collection of dried specimens of the common types of mollusks, echinoderms, hydroids, corals, and seaweeds adorns the corridors and stair landings, and in the collection room is found a large and fairly complete representation of the Adriatic fauna, including an extensive collection exhibiting the seasonal changes in the plankton of the Adriatic.

E

J

B

P

The marine equipment for field work in biological and oceanographical lines is exceptionally complete and carefully selected. The station possesses, in addition to rowboats and a sailboat, a motor boat, the Argo, 9 m. in length, with a draft of 0.7 m. The Argo is an open boat with steel hull, and a 12horsepower 3-cylinder Wolverine benzine motor, with reversible propeller, with fuel tanks in prow and stern, and a 2 m. overdeck at the stern for receiving and sorting the collection. A small mast forward serves for signaling purposes and a light metal framework carries a canvas top for protection against the sun, and canvas sides to shut out heavy seas when for circulation from first tank into second by stopping L'". needed. A small jolly

C

FIG. 46.-Cross section with projection of partition wall. Arrows indicate the direction of flow of water; A, end of tank; B, top of cement table; C, table support; D, floor; E, intermediate partition; F, salt water cocks; G, water level; G', level of plate glass sides and cement end of series; H, overflow ledge from

one aquarium to next; I, slot in cement plate glass; J, plate

pipe; L", riser section of outlet pipe; L''', descender section of outlet pipe; M, openings into outlet pipe for cleaning; N, inlet

glass sides; K, aquarium cement; L', horizontal section of outlet

pipe; 0, terminal glass tube of aerating apparatus in channel in cement; P, discharge into marginal trough of table; Q, by-pass

After sketches furnished by Professor Cori.

boat is carried on the after deck, and the reels for sounding and plankton work forward of the engine. Pump and tanks with seawater circulation provide for transportation of living animals.

The inadequacy of this small boat for the exploration of the Gulf of Trieste and its unsuitableness for work or travel in heavy weather led to the building of a larger boat after several years of careful planning. (See Cori, 1906.) This new boat, the Adria (Pl. XLV, B), is specially adapted to the work of biological exploration and is admirably equipped with all the mechanical devices needed for the work. All

45504°-Bull. 4-1)- -18

things considered, it is one of the best boats of its kind at any station in Europe, viz, a small boat to work from a central base of operations with a minimum cost for labor and fuel for short cruises, and yet affording sufficient power for rapid travel and the operation of the necessary machinery of exploration, and the room requisite for scientific operations and the scientific personnel.

The Adria is a wooden steamer with coppered hull, with length over all 20.5 m., beam amidships 12 m., depth of 2.4 m., draft of 1.5 m., and tonnage of 44 tons. She is built on the lines of the Norwegian fishing steamers, with low upper works and single mast forward, fishing deck forward, laboratory and cabins amidships, engine room and steering gear aft. She has a 75-horsepower Wolverine motor for benzine, petroleum, or alcohol, makes 9 knots per hour, carries 900 k. of benzine, and has a steaming radius of 450 miles, or fifty hours. She carries a crew of three and has berths for six scientists.

Electric

power from a 2-horsepower accessory gas engine and dynamo serves for the winch, used for dredging, etc., for the air compressor, pumps for sea-water circulation, and for electric lights. The cost of the boat was approximately 60,000 kronen or $12,000. A full description of the boat and its mechanical and scientific equipment will be found in a paper by Professor Cori (1909) in the fifth "Jahresbericht" of the Adria Verein.

The instrumental equipment for marine exploration includes, in addition to the customary instruments for navigation, an optical compass, a Potts mirror-goniometer for quick location of the position of the boat upon the chart, and the hydrographic equipment contains the Ekman current meter and water bottle, Richter thermometers, Assmann aspiration thermometers, and Fuess's slow-acting "Trager" thermometers for use on station buoys and in the study of shore muds and bottom deposits, areometers, and Sechhi disks for recording the transparency of the water. The biological equipment includes, in