OF THE MAKRAN SERIES. 375 



Genus TEMNOPLEURUS, Agassiz, 1841. 



The distinctions between this genus and TemnecMnus, Forbes, have been considered 

 on a former page in criticizing the zoological position of the forms which were included 

 in Temnopleurus by d'Archiac and Haime (Part ii, page 36). There is no doubt that 

 a fossil Temnopleurus occurs in the Indian Tertiaries, for there are numerous parts of 

 tests of a species of the genus in the Makran deposits. Unfortunately the apical 

 system is wanting in all ; but the peristome and the ornamentation, which give good 

 specific distinctions, are present. The species is not without its affinities with Salmads. 



1. Temnopleurus simplex, Duncan & Sladen. Plate LVI, Figs. 5-7. 



The test is broader than high, broadest at the ambitus, which is situated close to 

 the resting base, depressed and conical abactinally, tumid at the margin. Actinally 

 rather tumid, and sloping upwards around the very small and slightly cut peristome. 

 Ambulacra narrow. The pairs of pores are in simple series, there are three pairs to 

 each plate, and they are separated by well-developed convex-topped costse which 

 terminate either in small tubercles or in granules. The pores are on the actinal 

 surface of the costal ridges. The arrangement of the three pairs of pores to each 

 plate is slightly pronounced, and there is barely a trace of a curving. The ambulacral 

 plates are broader than high, and each has a primary tubercle which is crenulate and 

 imperforate, and is surrounded by a circle of granules, there being also a small 

 secondary at the aboral angle near the pores. The pits at the angles of the plates are 

 small and the furrows over the transverse sutures are small, or they may be absent in 

 young forms. 



The interradial plates have only one tubercle on each, but there is sometimes a 

 secondary at the inner angle as. well as at the poriferous side, and a ring of granules 

 surrounds the primary and separates it from the secondaries. The shape and size of 

 the interradial and ambulacral tubercles is much the same. 



There are numerous small granules and very small secondaries at the median line, 

 and the surface is depressed there near the apex. Median furrow distinct, but the 

 pits and furrows in relation to the transverse sutures are slight. "With growth, the 

 larger specimens have a barer median area and more distinct pits. 



Dimensions. Breadth 25, 19, and 18 millim. ; 13 and 10 millim. high. Peristome 

 only 5'5 millim. broad. 



Locality. Ras Malan, Makran coast. Survey-number G^A-- 



Illustrations of the Species in Plate LVI. 



Fig. 5. The test : natural size. 



6. Part of the test near the peristome : magnified. 



7. Ambulacral plate : magnified. 



