ANATOMY OF AMPHIOXTJS. 625 



glandular structure, may be regarded as performing the functions of a 

 hepatic organ. 



(1675.) The whole track of the intestinal tube, as well as the (so-called) 

 hepatic viscus, is covered internally with vibratile cilia. The ciliary 

 action, however, is more especially conspicuous in that part of the intes- 

 tine which lies beyond the green- coloured portion ; and it is here that 

 excrementitious matter begins to be formed, which may be observed 

 turning round and round with velocity in consequence of the surrounding 

 ciliary movement. 



(1676.) At the posterior part of the respiratory chamber, and close 

 to the abdominal pore, the microscope displays some small detached 

 glandular bodies, which Miiller thinks may be the kidneys ; he, however, 

 remarks that he could never discover them by dissection. 



(1677.) The ovaria consist of lax cellular tissue, surrounded with a 

 delicate but strong membrane, which is closed on all sides. They are 

 adherent by one side to the walls of the abdominal or, rather, thoraco- 

 ventral cavity ; elsewhere they are covered by the peritoneum. Costa, 

 who first recognized these organs, observed that in the males the testes 

 occupied the same situation as the ovaria. There are neither oviducts 

 nor vasa deferentia ; so that the products of the generative organs must 

 necessarily pass through the abdominal cavity and escape through the 

 abdominal pore, as is the case among the cyclostomous cartilaginous 

 fishes. 



(1678.) The description given by Miiller of the circulation of the 

 blood in the Amphioxus is extremely interesting. The circulatory appa- 

 ratus, while presenting a considerable resemblance to the normal arrange- 

 ment met with in other fishes, exhibits an equally strong analogy with 

 that of some of the Annelida in its division and distribution. 



(1679.) Miiller enumerates *, as belonging to the circulatory appa- 

 ratus of Amphioxus, the following parts: 1. the arterial heart (das 

 Arterienherz) ; 2. the bulbs of the branchial arteries (die Bulbillen der 

 Kiemenarterien) ; 3. the aortic arch, which discharges the functions of 

 a systemic heart (der herzartige Aortenbogeri) ; 4. the heart of the vena 

 porta3 (das Pfortaderherz)', 5. the heart of the vena cava (das Hohlvenen- 

 herz), the duties assignable to each being as follows : The arterial 

 heart (fig. 309, II) is a thick vessel of uniform calibre throughout, 

 situated in the median line, and running immediately beneath the 

 branchial chamber, between the arches forming the framework of that 

 cavity ; posteriorly this vessel is continuous with the heart of the vena 

 cava (n). Before the moment of contraction, the arterial heart is seen 

 to be filled with perfectly colourless blood ; but when fully contracted, 

 it is completely emptied (the interval between its contractions is about 

 a minute). From its sides are given off the bulbs of the branchial arteries 

 * "Ueber den Bau und die Lebenserscheinungen des Amphioxus lanceolatus" 

 Berlin Trans. 1842, 



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