. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 88 Mr. E. Ray Lankester's Zoological Observations The heart as knowji and described is an oval pellucid body, with a dense mass at each pole. During life it beats with marvellous rapidity, quite unlike the action of a heart, and suggesting (what I believe it is) a form of protoplasmic movement allied to the ciliary. The mass at each pole of the oval heart is seen in spe- cimens about two thirds grown, when dilute acid is added, to be a nucleated cell. From each of these extend
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 88 Mr. E. Ray Lankester's Zoological Observations The heart as knowji and described is an oval pellucid body, with a dense mass at each pole. During life it beats with marvellous rapidity, quite unlike the action of a heart, and suggesting (what I believe it is) a form of protoplasmic movement allied to the ciliary. The mass at each pole of the oval heart is seen in spe- cimens about two thirds grown, when dilute acid is added, to be a nucleated cell. From each of these extends, not a contractile membrane (as Avould appear from the figures of Gegenbaur, Foil, and others), but from twelve to twenty fine processes or filaments joining one cell to the other, leaving open spaces between them. The rapid contractions of these processes of the cells, which are not unlike (except in being fixed at both ends) those pro- cesses known as cilia, agitate the blood in which the heart is suspended; but there is no trace of blood-vessels connected with the heart. In specimens of Apjyendicularia furcata of full size the heart was seen to be a little more complex in structure; for at the base of each fibre or process of the two original large conical cells (which still retain their form and their large nuclei) is developed a small swelling with a nu- cleus (fig. 2). Moreover each of the fibres is now seen (when treated with picric acid) to possess a transverse striation, like that of the muscular fibres of the great tail or flabellum. I have specimens of A^ypendiadaria furcata^ treated with picric acid and mounted in glycerine, which exhibit admirably at the present moment this very remarkable structure of the heart. Histology of Sipunculus nudus. Every naturalist who visits Naples studies this very in- teresting and abundant worm more or less, and comes to a conclusion respecting its generative organs differing from those of his predecessors. [ can only briefly stat
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