WOODWAllD — SOME ACCOUNT OF BARRKTTTA. 



375 



in wliicli the plate is wanlitig, and the cardinal apparatus lies close to 

 the side of the shell instead of being at right angles to it.* AV^e 

 have already described and figured these ])eculiarities on former oc- 

 casions, and it will be sufficient now to propose the name JJorhignia 

 for II. hi oculatios and other hippurites (iigs. 6, 7), w'hich'^ha\'e no 

 ligamental inflection, and a second subgeneric title, Barre.ltia, for 

 the Jamaica fossil, which presents the further peculiarity of an indefi- 

 nite number of pallial duplicatures extending all round the margin of 

 the lower valve. 



It still remains to speak of the shelly process from the upper 

 valve («'), seen in both our sections, descending into a ]nt between 

 the posterior tooth {t!) and the principal duplicature {m). ]n the 

 paper previously referred to we luiA'e described this process as the 

 sup})ort of the posterior shell-muscle, having found characteristic 

 indications of the muscular scar within the cavity which receives it. 

 Since then, Professor Bayle, of the Ecole des Mines at Paris, lias pub- 

 lished a description, with excellent figures, of some very complete 

 examples of llipjmriies radiosus. These specimens do not show any 

 peculiarity unknown before, but they are far more perfect than the 

 best we had ever seen, and exhibit in complete relief the extra- 

 ordinary cardinal apparatus of the upper valve, of which our previous 

 knowledge was chieliy obtained from sections. Owing to the condition 

 of his specimens, ]M. Bayle has had the good fortune to procure, in a few 

 weelis, better illustrations than we could obtain with much labour, 

 continued at intervals for several years. Nevertheless, the very state 

 of our materials has compelled a closer and longer examination, which 

 we trust has not been thrown away ! M. Bayle has quoted our views 

 very fairly, and we hope he will yet see reason to adopt them. His 

 memoir was accompanied by a critical notice froiu M. Deshayes con- 

 taining the following passages : — 



" Le travail de M. AVoodward est le plus complet qui ait ete public 

 sur I'ensemble des lludistes. Cependant il reste bien des parties qui 

 auraient demande une discussion plus approfondie, des caracteres qui, 

 au ])oint de vue zoologique, auraient pu etre plus largement exposes 

 et discutes." 



" Avec le travail de M. Woodward, on pouvait encore concevoir 

 des doutes sur quelques parties, et notamment sur le nombre et la 

 position des muscles. Ce natnraliste suppose I'existence d'uii 

 muscle adducteur des valves de chaque cote de la charniere, exacte- 

 ment comme dans les Splierulites ; ce second muscle se serait at- 

 tache dans la prolbndeur de I'une des cavites cardinales de la valve 

 inferieure et au sommet de I'une des apophyses de la valve superieure ; 

 maia les pieces preparees par M. Bayle ne laissent plus de doute ii ce 

 sujet ; les deux impressions musculaires sent portees d'un nu^Muo 

 cote, par suite d'un renversement de I'animal, com])arable a ce (pii 

 existe chez les lIi|)popes et les Tridacnes, ainsi que M. Bayle lui-mrme 

 I'a parfaitement compris ; tout ra[)pareil musculaire, se trouvant 



* 'Manual of the MoUiisca,' pt. ii. p. 2?'.) (KS51), and Quarterly Journal of ibc Gcol. 

 Soc, vol. \i. p. 40, 1855. (Road May 21, 185-1.) 



