tendency is towards a square shape ; in the deeper sinking, in a 

 longitudinal depression, of the coronal extremities of the nasal 

 bones in the Tiger than in the Lion; in the bounding of this de- 

 pression above in most oi \.he. Tigers crania by a small but distinct 

 semilunar ridge, which is not found in those of the Lion; and in the 

 larger comparative size, chiefly in their transverse diameter, of the 

 infraorbitalyoram/Ha in the Lion. Thesejbramina, it is curious to 

 observe, are double either on one or both sides in the only four 

 crania examined of Lions which were known to be Asiatic, while in 

 all the others thejbramen was single on each side. 



Specimens were exhibited of Placunanomice from the collection 

 of Mr. Cuming, and the following Notes by Mr. Broderip respecting 

 them were read. 



Genus Placunanomia. 



Since my publication of this genus in the ' Proceedings of the 

 Committee of Science and Correspondence,' (Part II. p. 28.) Mr. 

 Cuming has found among his stores the following three species in 

 addition to Plac. Cumiugii, which I have already recorded, 



Placunanomia rudis. Plac. testa sordide alba, crassd, concen- 

 trice irregularitcr corrugatd, intiis nitide politd : alt. I|, long. If, 

 lat. I poll. 

 Hab. in India Occidentali. 

 Obs. OstrecB edulis speciem referens. 



Mr. Cuming detected this Placunanomia attached to a Spondylus 

 croceus, — W. J, B. 

 /3 A? Placunanomia foliata. Plac. testd snbdiaphand, subcirculari, 

 rtidi, subfoliatd, sordide alba, intus splendente ; valvce superioris 

 medio purpureo-fusco : alt. H, long. H, lat. -f\ poll. 

 Hab. in sinu Guayaquil Columbiae Occidentalis. (Isle of Mu- 

 erte.) 



Dredged up attached to a dead Pinna from a bottom of sandy 

 mud, at the depth of eleven fathoms. 



The surface of the inside of the lower valve is uneven but lustrous, 

 and of a hue somewhat approaching to golden. The inside centre 

 of the upper valve is of a rich purple brown. The outer surface of 

 the lower valve, which has been attached throughout its whole ex- 

 tent, bears a somewhat crystalline appearance ; and this observa- 

 tion may be applied to the adhering surface of Plac. rudis. In the 

 last-mentioned species this portion is comparatively small, and the 

 eye will immediately detect it from the contrast which it affords 

 with the dull exterior of the part which was free. — W. J. B. 

 Placunanomia echinata. Plac. testd subtumidd, valvd supe- 

 riore seriatim echinatd, limbo purpurascente: alt. li, long. If, 

 lat. 3 poll. 

 Hab. ad Insulam Nevis. 



Dredged up attached to shells, by Mr. Powers, from sandy mud 

 at a depth of six fathoms. 



