Boring in shells and calcite crystals was investigated, sing a new type of reconstitution culture. No free acid was detected, and no detectable q~lantity of calcium \\,as p~~t in solution by the sponge. However, acid action is indicated by restriction of boring to c a l c i~~~n carbonatc. Conchiolin is penetrated with difficulty. Cells in contact with the substratunl form a reticululn of fine pseu?opodia and lilamellts; a correspondi~ig pattern of lines is etched into the calclte. 'I'he areas so markcd out are the same size and shape as the fragments discharged by the sponge. These fragments arc identical \vliether from shells or calcitc crystals; their faces are curved but their edges sharp. Apparently the cytoplasmic filaments insinuate the~nselves into calcite by secreting minute alnounts of acid, and undercut fragrnellts which are carried through the sponge parenchyma to excurrent canals.Cliona is a cosmopolitail genus of nlarine siliceous spoilges (F. Clionidae, 0. Haclromerina, C1. Demospongiae), remarltable for the habit of living in tu!lnels and galleries bored in limestone, coral, ancl the shells of n~olluscs. The damage inflicted by Cliona on various mollusc fisheries and on limestone brealrwaters invests the genus with some economic importance, and spongeriddled shells ancl stones are familiar objects to the naturalist on the seashore. The manner in which the galleries are excavated has therefore attracted the researches of several biologists, and the speculations of many more. This paper will recount some of the results of an investigation into the biology of boring sponpes, sponsored by the Fisheries Research Board of Canada because of the deleterious eRects of the sponges on the oyster and scallop fisheries of eastern Canada. The work was carried out a t the Board's Biological Sub-station, situated on Malpeque Bay on the north shore of Prince Edwarcl Island, near Ellerslie. Studies were largely confined to Cliona celata, the prevalent species in that area. Historical NoteGrant (3), who first described Cliona celata, believed that his new "zoophyte" dwelt in burrows made by worms. Bowerbank (1) shared this opinion. Hancoclr (4,s) refuted Bowerbanlr's arguments, and made it clear that Cliona bored its o~v n holes; he suggested that this was done by grinding with the spicules. However, Nassanov (9,lO) showed that Cliona larvae began to bore before they possessed spicules.Nassanov had described the fragments of shell discharged by boring sponges. These, and fragments of conchiolin from bored oyster shells, were figured by Topsent (12), who pointed out that since coilchiolin is bored in the 'Manuscript

Larvae of Cliona celata and Microciona prolifera swim constantly upward, or at the surface, until 20 to 30 hr old, then always swim vertically downward. This behavior is not oriented by chemical of thermal gradients and is independent of light.

No abstract

Use of the scientific method to achieve valid generalizations in biology rests on classifications. If a proposition is empirically known to be true of several organisms, it is normally postulated, as a hypothesis to be tested, that it is true of all members of the smallest taxon to which all the known instances belong. If possible, further instances testing the hypothesis, are sought among the organisms most distantly related to those already known while still within the taxon about which the generalization has been postulated.

A standard nomenclature for chimpanzee chromosomes is proposed, based on banding patterns and measurements. Comparison of chromosome lengths suggests that the total amount of chromosome material is approximately the same in the human and chimpanzee. Correlation of banding patterns and measurements confirm that the chromosomes of the two species differ by rearrangement of heterochromatic material, several pericentric inversions, and at least one translocation.