6 FOSSIL CIRRIPEDIA. 



uot heard of any Cirripecle liaving been as yet discovered in the Upper Oolite, or in the 

 Wealden formation. During the deposition of the great Cretaceous System, the Lepadidae 

 arrived at their cuhiiinant point ; there were then three genera, and at least thirty-two 

 species, some occurring in every stage of this system. Besides the thirty-two certainly 

 known cretaceous forms, and several other doubtful ones, I beheve that very many more 

 will yet be discovered ; I infer this from the fact, that in almost every collection lent to 

 me for examination, although very small, I have found some new species. I have three 

 or four species from the Gault ; from five to eight in the Lower Chalk, and from nine to 

 twelve species in the Upper Chalk (not including the Faxoe, Scanian, and Maestricht 

 stage) ; and of these nine to twelve species, five have been found by one collector, Mr. Fitch, 

 in one locality, namely near Norwich. In Scania M. Angelin has found no less than nine 

 or ten species, all belonging to the upper or Maestricht stage of the Chalk. These fossils, 

 judging from the habits of recent species of the same genera, were probably attached to 

 fixed, or nearly fixed, objects at the bottom of the sea. Now at the present day, of attached 

 Pedunculata (reckoning even Crustacea andEchhiida? as fixed objects), the whole Mediter- 

 ranean and New Zealand can boast each only of three species, in both cases including 

 Alepas, which is destitute of calcified valves and therefore not likely to be fossilized ; 

 Australia has three species ; Madeira has four species, including one with very small and 

 imperfectly calcified valves ; the great Phillipine Archipelago, however, has afforded, owing 

 to the labours of Mr. Cuming, as many as five species, though including one with horny 

 valves, and a Lithotrya which lives embedded on the beach. Therefore since we already 

 have nine or ten fossil species from one locality, and from the same stage of the chalk, 

 we may admit that the pedunculated Cirripedes arrived during the upper part of the 

 Cretaceous system at their culminant point. 



Although, for this family, the number of species were considerable during the Cretaceous 

 period, the individuals were mostly rare. I infer this from the small number of specimens 

 in all collections ; for instance, Mr, Fitch, who has assiduously collected for twenty years 

 in the chalk near Norwich, possesses in his entire collection only nine keel-valves of Scal- 

 pellmn maximum, and six of S.fossula; he has two Scuta (and with regard to these valves, 

 it must be remembered, that each individual had two) of Pollicipes striatus, two of 

 P.fallax, and four of P. Angelini. This occasional want of a relation, within the same 

 region, between the number of the species in any given genus, and of the individuals 

 appertaining to such species, is a singular fact, and has been strongly insisted on by Dr. 

 Hooker, in regard to the Coniferous trees of the southern hemisphere : one would 

 naturally have expected, that where circumstances favoured the existence of numerous 

 species of a genus, they Avould likewise have favoured the multiplication of the indi- 

 viduals in all or most of such species ; but this, as we here see, has not always been 

 the case. 



In the Eocene, Miocene, and Pliocene Tertiary deposits, I know only of two species of 

 Scalpcllum, and two of Pollicipes, with indications of two or three other species, all distinct 



