TERTIAET MICROZOIC FORMATIOITS OF TEHSTIDAD. 535 



five, very rarely six, and there is no obvious external difference in 

 structure between the rays and the centre of the disc. The internal 

 structure as shown by sections is similar to that of other species of 

 Tinoporus, but recalls that of Orbitoides also. 



Nodosaria raphanistrum. — The specimens from the Orbitoides- 

 bed and the Ally Creek shell-bed are well-grown, large, strong, and 

 closely-ribbed. They are seldom procured entire owing to the 

 nature of the matrix. The examples from the Globic/erina-heds are 

 rare and much smaller and weaker. 



Orbulina. — I have opened several specimens and have in nearly 

 all cases found them to contain the internal polythalamous skeleton. 



Webbina. — The specimens of Webbina clavata are usually found 

 adherent to Ammodiscus incertus and other foraminifera. 



Spiroplecta americana. — The few examples of this species which 

 have been found are black, except on the prominent parts which 

 are white, as if the specimens had been plunged into ink and quickly 

 withdrawn. This coloration is no doubt due to infiltration by 

 iron. 



Many of the foraminifera are tinged with colour. Some, no 

 doubt, retain a trace of their original hue. Such, for example, as 

 Bigenerina, which is usually brown, but sometimes (especially 

 B. capreolus) grey. 



Globigerina is usually of a brilliant white, and so are the Nodo- 

 sarice, both being rarely brown or black. Many of the arenaceous 

 forms are often of some shade of brown. Black glistening speci- 

 mens are occasionally seen. 



The Pointapier species are for the most part minute, the Globi- 

 gerince being almost the only forms of full size, and these are 

 usually white, the other foraminifera being mostly tinged with a 

 deep red colour or filled with matter of that hue. Some, however, 

 are bright and polished and retain their original structure very per- 

 fectly. The minute Bolivince, which are numerous, appear to show a 

 spiral commencement like Sjpiroplecta. When mounted in Canada 

 balsam it is difficult to distinguish these from the minute Textularice 

 of the Chalk or of the Naparima rocks. 



§ 6. General Conclusions. 



The Eocene moUuscan faunas of Trinidad show no near alliances 

 with any other known faunas. In this they differ from the well- 

 known and easily recognized Miocene fauna found in Haiti, 

 Jamaica, Cuba, Cumana, Trinidad (Caroni Series), and other locali- 

 ties. Nevertheless a few of the forms have been found elsewhere. 

 The Echinolampas ovumserpentis, Terebratula carneoides, and JRanina 

 porifera of the Naparima Beds recur in the Eocene of St. Bartholo- 

 mew's (north-eastern West Indies), and I have already noted that 

 the same beds have a Nucula and a Leda in common with Barbados. 

 It is only with doubt that the name of Natica p>hasianeUoides, a 

 Miocene fossil of Cuba and Jamaica, can be assigned to the imper- 



