96 REPORT — 1856. 



The next point that claims attention, is that relating to the pyriform vesicles 

 described by Mr. Huxley, of which there are five in Waldheimia Justralist. In the 

 other species that I have examined they do not appear to be so numerous ; one, 

 however, is aUvaj's present. This is attached to the dorsal surface of the stomach 

 on the median line ; and I have satisfactorily ascertained that the " ridges " on the 

 alimentary tube mentioned by Mr. Hux'ey as connected with it are really vessels; 

 likewise that these vessels pass along the gastro-parietal and ilia-parietal bands of 

 that gentleman, and thus reaching the ovarian sinuses run along their inner wall 

 and become attached to the border of the membranous ridge which suspends the 

 ovaries. They then course along the entire length of these organs, however ramified, 

 forming the axis around which the ova are developed. Two other vessels are in 

 connexion with this system ; one, passing backwards from the tube that runs along 

 the ilia-parietal bands, goes apparently to the pedicle ; the other, which is larger than 

 the rest, extends along the middle line of the stomach at Ihe base of the membrane 

 which divides the liver, and which has been denominated mesentery, and enters the 

 vesicle in front. The other four vesicles are considerably smaller than that attached 

 to the stomach, the walls of which are muscular, and are appended to the ovarian 

 vessels as they enter these organs. 



From the above facts it may be safely concluded that in this apparatus we see the 

 true vascular system of these animals ; and yet it must be allowed to be rather of 

 a peculiar character. The vesicle suspended from the stomach is undoubtedly the 

 heart, and the vessels passing from it backwards are as assuredly arteries. The 

 vessel which passes along the stomach and approaches the vesicle in front, is appa- 

 rently the channel by which the blood is returned from the aerating surface ; but I 

 have hitherto failed to ascertain by what path the blood reaches this channel. It 

 would not, however, be difficult to conjecture, were it not better to wait the result 

 of further investigation. The central organ of propulsion is here of a very simple 

 form,— a mere vesicle scarcely higher in organic mechanism than the pulsating 

 vessel of the Ascidian ; there is no auricle, no pericardium. Its powers must neces- 

 sarily be feeble; hence probablythe additional vesicles appended to the ovarian arteries, 

 which are apparently accessory pulsating organs. 



With respect to the muscular system, I now find that the accessory cardinals are 

 not always distinct from the cardinal muscles ; but that the two occasionally coalesce, 

 forming only one muscle. This is the case in Waldheimia cranium. It is also worthy 

 of remark, that the dorsal pedicle muscles are not invariably attached to the hinge 

 plate. In W. cranium and Ternbratulina caput -serpentis they have their origin in 

 the valve itself between the adductors, extending nearly as far forward as they do. 



I have nothing very positive to communicate on the reproductive system ; it does 

 not, however, appear conclusive that the Brachiopods are dioecious ; but, on the 

 contrary, I find that the so-called ovaries or testes in Waldheimia Australis are really 

 composed of two parts, — one yellow and minutely granular, the other red and 

 formed of large vesicles. In some specimens the former portion was developed into 

 eggs ; but I have not yet observed spermatozoa in the red part, which is probably 

 the male secreting organ. This would appear to be likely from what I have observed 

 in Lingula. In this genus the ovary is developed within the visceral chamber, of a 

 yellow colour ; and on the inner surface of the dorsal and ventral walls of this 

 chamber there ramifies a red dentritic organ which is made up for the most part of 

 large vesicles like those of the red portion of the genitalia of Waklh^imia ; and in 

 this organ I have found what I believe to be spermatophora filled with spermatozoa. 

 Thus it would appear that Lingula is androjjynous ; and if so, it is probable that 

 the other Brachiopods may likewise have the sexes combined in the same individual. 



I shall refrain on the present occasion from entering upon the nervous system, 

 which is beautifully developed, only remarking that it requires further elucidation ; 

 and in conclusion may express a hope that I shall be able, before terminating the 

 investigation on which I am now engaged, to clear up what still remains obscure in 

 the anatomy and physiology of these interesting animals, and that at no distant 

 period I shall be in a position to publish a detailed and illustrated account of these 

 matters. With a view to this I have already made numerous drawings. 



