V. On the structure of the gills of the Lamellibranchia

Abstract

The comparative study of the gill structure of the Lamellibranchia may be said to date from 1875. Williams, it is true, had in 1854 published two papers on the subject, but owing to the fact that the morphological relations of the gill lamellæ to the gill axis and to other parts of the body were not then understood, and owing to the somewhat wild and fantastic mode of argument affected by this author, they cannot claim to be seriously regarded as the first important contribution to the literature of the subject. The few remarks on the different types of Lamellibranch gills made by Leuckart in 1848 (p. 113), Hancock in 1853 (p. 290), and Duvernoy in 1854 (p. 37) are of interest only from an historical point of view, and do not come within the range of the modern treatment of the subject; and the excellent figures and remarks on gill structure made by Deshayes in 1844-1848 cannot claim to be considered in the present connection, being purely descriptive and not comparative. It was Posner who first attempted a systematic investigation of the subject, and in his memoir of 1875 he discussed, not very astutely, the minute structure of the gills of Anodonta and eleven other genera of bivalve Mollusca. Some fifteen months later Peck, who in 1875, independently of Posner’s work, had commenced a similar investigation, published his important observations on the gills of Area, Mytilus, Dreissensia and Anodonta . It was this paper which first placed the comparative study of the gills upon a sound basis. The investigation was conducted in the laboratory of Professor Ray Lankester and under his direction, and the working hypothesis around which the paper was written, and which has stood the test of time ever since, was, as the author explains, supplied by Professor Lankester. An adequate terminology was propounded for the grosser and finer parts of the gill, and this terminology remains in general use at the present day.