Page:Proceedings of the Royal Society of London Vol 4.djvu/484

Rh extensive, and the spleen is of larger dimensions and greater elas- ticity.

The splenic corpuscles are thickly scattered throughout the cellu- lar parenchyma of this organ ; and from each corpuscle there arises a minute lymphatic vessel ; the interlacing of adjacent lymphatics giving rise to a fine and extensive net-work. The trunks of these vessels enter into the Malpighian glands, and again ramifying, form a lymphatic plexus in the interior of these bodies. The fluid con- tents of these vessels, which had been before pellucid, is now found to contain white organic globules, similar in every respect to those observed in the fluid of lymphatic glands in other parts of the body. The author considers the secretion of this fluid, which appears to be identical with the contents of the lymphatic glands, as being the peculiar function of the splenic parenchyma.

A few illustrative drawings and diagrams accompany this paper.

2. " On the Structure and Developementof the Nervous and Cir- culatory Systems, and on the existence of a complete Circulation of the Blood in Vessels in the Myriapoda and the Macrourous Arach- riida." By George Newport, Esq. Communicated by P. M. Roget, M.D., Sec. R.S.

This paper is the first of a series which the author proposes to submit to the Royal Society on the comparative anatomy and the developement of the nervous and circulatory systems in articulated animals. Its purpose is, in the first place, to investigate the minute anatomy of the nervous system in the Myriapoda and the Macrou- rous Arachnida, and more especially with reference to the structure of the nervous cord and its ganglia ; and thence to deduce certain conclusions with respect to the physiology of that system and the reflex movements in vertebrated animals ; secondly, to demonstrate the existence of a complete system of circulatory vessels in the Myriapoda and Arachnida ; and thirdly, to point out the identity of the laws which regulate the developement of the nervous and circu- latory systems throughout the whole of the Articulata, and the de- pendence of these systems on the changes which take place in the muscular and tegumentary structures of the body, as, in a former paper, he showed was the case with regard to the changes occurring in the nervous system of true insects.

The first part of the paper relates to the nervous system. A de- scription is given of this system in the Chilognatha, which the au- thor was led, by his former investigations, to regard as the lowest order of the Myriapoda, and approximating most nearly to the Annelida. He traces the different forms exhibited by the nervous system in the principal genera of that order, the most perfect of which are connected on the one hand with the Crustacea, and on the other with true insects. Passing from these to the Geophili, the lowest family of the Chilopoda, which still present the vermiform type, the nervous system is traced to the tailed Arachnida, the Scorpions, through Scolopendra, Lithobius and Scutigera ; the last of which tribes connects the Myriapoda on the one hand with the