undescrihed Oi(j<ut in Liinulus. 2o7 



form, and, twenty hour.s after the portion of the parenchynui 

 submitted to mieroscopie examination, vibrated to and fro. 

 I am remindeil in the vil)ratin:^ movements of these bodies 

 of Siebold's deseription ('Anatomy of the Inverteljrates 'j of 

 similar bodies in the renal organs of tlie Lamelliljranehs, 

 i. e. the gland of Bojanus. He says ip a footnote, p. 214 

 (Burnett's translation) : — " If the walls of these organs are 

 prepared in any way for microscopic examination, a part of 

 their parencliyma separates into a vesieulo-granuhir mass, the 

 particles of which have a very lively dancing motion. Tlie 

 motions are due to portions of ciliated epithelium adhering to 

 the cells and granules." 



In other portions of the outer reddish part of the gland, 

 where the pigment (?) masses are wanting, the mass is made 

 up of fine granular cells, not nucleated. Other cells have a 

 large nucleus filled with granules and containing nucleoli. 



In the yellowish or, as we may for convenience call it, the 

 medullary portion are scattered about very sparingly what are 

 probably the round secreting cells. The nucleus is very large 

 and amber-coloured, with a clear nucleolus ; others have no 

 nucleolus ; and the small ones are colourless. 



I am at a loss to think what this gland, with its active 

 secreting cells filled Avith a yellowish fluid, can be, unless it 

 is renal in its nature. This view is borne out by the fact 

 of its relation with the hepatic and great collective vein. If 

 future examination shows some outlet into the venous circu- 

 lation, then its renal nature would seem most probable. No 

 other organ that can be renal in its nature exists in Linudus. 

 In its general position and relations it is probably homologous 

 with the green gland of the Decapod Crustacea and its homo- 

 logue in the lower orders of Crustacea, which is suj)posed also 

 to be renal in its nature. It may also possibly represent the 

 organ of Bojanus in the Mollusca, which is said to be renal 

 in its function. It perhaps represents the glandular portion 

 of the segmental organs in worms. That so large and im- 

 portant a gland is an embryonic gland, in adult life aborted 

 and disused, is not probable ; nor is there any good reason for 

 regarding it as analogous to the suprarenal capsule of the 

 vertebrates, analogues of which are said by Leydig to exist in 

 Puhidina and Pontohdella. 



Reasoning from their histological structure and by exclu- 

 sion, it seems not improbable that these glands are renal in 

 their nature, and homologous with the green glands of the 

 normal Crustacea. They seem also homologous with the 

 organs described by M. A. Giard in the Rhizocephala, and 



