GENUS PATELLINA. 229 



40 1 . Gcograpldcal Distribution. — The recent examples alike of the simple and of the baculate 

 types of Tinoporvs are found in greatest size and abundance in the Australian and Polynesian 

 seas, occurring chiefly in the shelly sands of rather shallow water ; and T. bamJntm does not 

 appear to range far beyond those regions. I am informed by Mr. Denis Macdonald (late of 

 H.M. surveying ship, " Herald"), that on some annular coral islets he has met with Orbito- 

 lites and Tinojwrus baailatus in most extraordinary quantity, not only on the windward side 

 of the external shore, but also in their internal lagoon, into which these bodies are washed 

 by the surf, and in which they gradually accumulate to such an amount as to have an im- 

 portant share in filling it up. The small spherical forms of T. vesicularis, on the other hand, 

 are for the most part inhabitants of deep waters, being brought up in dredgings from muddy 

 bottoms and shell-sands ; and they have also a wider geographical range, having been found 

 not only in the Australian and Polynesian seas, but in the East and West Indies, at Mazatlan 

 on the coast of California, in the neighbourhood of Teneriffe, in the Mediterranean, and even 

 on the British coasts as far north as Arran. 



402. Geograpliical Distribution. — The obliteration of the internal structure of the earlier 

 fossil specimens which we believe ourselves justified in referring to this type, prevents us from 

 stating with certainty in what strata its first remains occur. From the evidence of external 

 form and surface-markings, however, it is pretty clear that some of those small spheroidal 

 bodies in the Greensand, and a large number of those occurring in the various beds of the 

 Cretaceous series, which have been regarded as Spongeous, are truly referable to the simple 

 form of the genus Tinoporus. If so, they are not only by far the largest examples of this type, 

 but are also amongst the largest of the Foraminiferous group. The Cretaceous period would 

 seem to be that in which this type attained its maximum of development; for although 

 examples of it occur in the Nummulitic limestone, and in the later Tertiaries of Palermo, 

 Bordeaux, and San Domingo, these are not of larger dimensions than the recent specimens. 

 The " baculate" form of this type cannot be distinguished with certainty in fossil specimens 

 from Calcarina, by external characters alone ; so that it is as yet uncertain whether any of 

 the radiate and stellate bodies which occur in the Maestricht Chalk and in the Nummulitic 

 Tertiaries, are or are not the ancestors of the similar organisms at present so abundant on the 

 reefs and islands of the great Coral Sea. 



Genus XX.— Patellina (Plate XIII, figs. 16, 17). 



403. History. — Some of the large fossil forms which seem properly to belong to the genus 

 now to be described, have been referred to the genus Orbitolina (D'Orbigny), whilst another has 

 received from D'Orbigny the designation, Cyclolina, and another has been described by 

 Mr. Carter (xxiii «) under the name Comilites ; and its minute recent representatives also have 

 been referred by Messrs. Parker and Rupert Jones (lxxix) to the genus Orbitolina. For the 

 reason already stated (^ 390), however, I think it undesirable to adopt the generic term Orbi- 

 tolina for this type, any more than for the last; and as the definition given by D'Orbigny of 

 his genus Cychlina is so unsatisfactory as to leave the true character of its type in complete 



