1. An account has been given of the techniques used by the present authors and by Premysl Bohuslav, in dealing with invertebrate tissue culture. 2. In aseptic tissue cultures of the wall of the mantle-cavity of Helix, the amoebocytes wander out and become much flattened. The pseudopodial membranes of Goodrich are well developed, but intercellular connecting fibrillar pseudopodia are rarer, and the outgrowing cells do not organize a connective tissue network to such a degree as in septic mounts. 3. In older ex-plants, the Golgi apparatus of the amoebocytes breaks up into granules which become scattered throughout the cell, as claimed by Ludford for rabbit embryo cells in tissue culture, and later by Saguchi for both chick and rabbit. 4. Having regard to the work of Ludford, Saguchi and the present authors on the modification of the Golgi apparatus of tissue-cultured cells, statements concerning the Golgi apparatus in general cytology, which have been made on evidence obtained by studying tissue-cultured cells, are of doubtful value. 5. In Helix tissue cultures, as in the flat worms studied by Mrs. Murray, there is good evidence that cells divide by amitosis. 6. Compared with vertebrate tissue cultures such as those of the chick heart, the outgrowing cells of Helix mantle-cavity ex-plants do not make flat sheets of cells, but tend to form networks, surrounding spaces of a fairly definite size and appearance. 7. The ingestion of bacteria by Helix amoeboctyes does not occur in the first instance, the cells attacking pigment granules, and only later ingesting bacteria after the latter have become very numerous.