290 Royal Society : — 



seum, and demonstrates the former existence in that continent of a 

 land-hzard considerably surpassing in bulk the largest species now 

 known. The characters are chiefly derived from vertebrse, partially 

 fossilized, equalling in size those of the largest existing Crocodiles ; 

 they are of the ' proccelian ' type, but present lacertian modifica- 

 tions, and closely agree with those in the great existing * Lace-lizard ' 

 of Australia {Hydrosaurus giganteus. Gray), of which individuals 

 upwards of six feet long have been taken. A generic or sub- 

 generic distinction is indicated by the comparatively contracted area 

 of the neural canal, and by the inferior development of the neural 

 spine, of the fossil vertebrae, which have belonged to an indivi- 

 dual not less than twenty feet in length, calculated from the vertebrae 

 and proportions of the body of the existing Hydrosauri. For this, 

 probably extinct lizard, the name of Megalania prisca is proposed. 



The results of an extended series of comparisons of its vertebrae 

 with those of recent and extinct Sauria are also given. 



"Researches on the Foraminifera. — Part III. On the Genera 

 Penerojjlis, Operculina, and Amjyhisfeginu.'" By W. B. Carpenter, 

 M.D., F.R.S. &c. * . 



In his preceding memoirs, the author has shown that two very 

 dissimilar types of structui'e present themselves among Foraminifera, 

 one characterized by its simplicity, the other by its complexity. In 

 the former, of which Orhitolites, Orbiculina, and Alveolina are typi- 

 cal examples, the calcareous skeleton does not present any definite 

 indications of organization, but seems to have been formed by the 

 simple calcification of a portion of the homogeneous sarcode-body 

 of the animal ; that sarcode-body is but very imperfectly di^dded 

 into segments, the communications between the cavities occupied 

 by these segments being very free and irregular ; the form of the 

 segments themselves, and the mode of their connexion, are alike in- 

 constant ; and even the plan of growth, on which the character of 

 the organism as a whole dej)ends, though preserving a general uni- 

 formity, is by no means invariably maintained. In the latter, to 

 which Cycloclypeus and Jleterostegina belong, the calcareous skele- 

 ton is Jbund to })resent a very definite and elaborate organization. 

 The several segments of the body are so completely separated from 

 each other, that they remain connected only by delicate threads of 

 sarcode. Each segment thus isolated has its own proper calcareous 

 envelope, which seems to be moulded (as it were) ujjon it ; and this 

 envelope or shell is perforated with minute parallel tubuli closely 

 resembling those of dentine, except in the absence of bifurcation ; 

 the partition-walls between adjacent segments are consequently 

 double, and arc strengthened by an intermediate calcareous deposit, 

 which is traversed by a system of inosculating passages that seems 

 properly to belong to it. The form of the segments, their mode of 

 communication, and consequently the general plan of growth, have 

 a very considerable degree of constancy ; and altogether the ten- 

 dency is strongly manifested in this type to the greater individuali- 



