BRAcmopoDi. 495 



and are situated in the Ter. Jlavescena, at the back part of the 

 viaceral cavity, on the dorsal aspect of the intestine, one on each 

 side of it3 upper or anterior half. If the dorsal ralTe and corre- 

 sponding lobe of the mantle be removed, and the " mnsculi retractorfcs 

 superiores" be gently divaricated, or the mesial fasciculi carefully 

 removed, the delicate membrane of the venoaa sinuses, continued 

 from the margin of the basal aperture of each auricle, is immediately 

 exposed, and is so transparent as to permit the plicated stmctore of 

 those cavities to be clearly seen.* If the viscera be exposed by a 

 ade view, as in fig. 186, the heart (r, #) of the side exposed will be 

 seen behind the beginning of the intestine. 



The ventricle in each heart is a smooth, feebly-muscular cavity, 

 from which are continued what have appeared to me to be arteries t ; 

 the largest ramified on the two halves of the mantle lobes nearest 

 the ventricle, the smaller one proceeding to the Tiscera and Hmaeieg. 



The auricular c-avity consists at the half next the Tentri^ rfa 

 plicated muscular coat, in addition to the membranous <ne; but 

 at the other half, next the venous sinuses, of Tenons iwe«brane 

 only : the latter might be termed the auricular sinus, the former 

 the auricle proper. The proper auricle presents the form of an 



" simple, tfam-coated. pyriform sacs." " Es 

 formige Sicke." Vogt sabsequently (" Zoologisc^ ^foi^" 1851, toL L |k 285) 

 recogiui«d the aarkalar AxmtXex of the part, in JLimgula, irhieh is so deambei. 

 in Terebratula (CCCEL 1S45. p. -292}. 



Mr. Hoxley, ^ho erroneoaslv, as he afterwards aAmawlfsigeA, ascribed this 

 discoverr to Vogt, specL&es it as ~the trae em^lez aUtfie of Ae hesit.'* 



(cccii p. 111.) 



• CCCIII. pL iii- 1, 1. 



t The best demonstAdon I have been able to make of Ae Tieealar system is 

 that sbovn in the injected prepaiatkios 993 A and B (X. voL iL p. 74\ aad ^—c 

 portiealarly described in CCCL (18-33), p. 1^4. '^In oo£ of the speeoMM (of 

 OriictJd) I sacceeded La injecting the vessels of one lobe of Ae wirtlr froai tms 

 of the ventricles -, in this injecte<i prepaiatiow ihac erido^lj af p tared a saall 

 nninjected line (ic' fig. 13), as in the Tere&rahd^y wnomjanjmg eadk of Ae larger 

 branchial veins, mmun^ akmg Ae centre of every tronk ; sad i 

 clade to be branchial arteries : if they -were retractile ■mcIcj of ±; =:zr 

 might be expected to have a straighrer coarse."' 



If it be trae that Mr. Hanoi'ck has " arrived at the 

 arteries exist" (CCCIX. p. 112 i in the sense that tbe 

 described have no existence, I feel no doabc that 

 excellent observer -wiR conrinee him of the aecvracy of my ir i 



figures (CCCL pL 22, fig. 11, pL 23, fig. 1 1.) The irta y efa r^ 

 of the parts is another matto-. Togt adopts my origiBal idea. ^<. ::^_ .^ :-c 

 honrfo^oos part (CCCVIIL tab. iL fig. 14. i) as a 'UatgefiKSL* b all my me- 

 moirs I have caQed attamon to the relatioa of the genefstive parts to the pallial 

 vessels, and I have figured the ovaria as being developed from the so-calle'i 

 arteries, in CCCIIL pL 2, fig. 2, 11. 



