OF WESTERN SIND. 67 



The shallow groove of the periproct has a very small ornamentation, which merges 

 into that of the sharp truncation. 



Length of specimens l^g and li% inch, breadth 1-^ and ^ inch, height ^q and 

 •^ inch. 



Locality. In the Ranikot series, north by east of Petiani, west of Kotri. Survey- 

 numbers G ?-ff and G ff f.. 



Illustrations of the Species in Plate XV. 



Fig. 7. A specimen of the test, from above. 



8, The transverse section. 



9. The floscelle and ornamentation : magnified. 

 10. The ornamentation of part of an ambulacrum. 



Genus RHYNCHOPYGUS, D'Orhigny, 1855. 



Test of small or moderate size, depressed, elongate, convex above, concave beneath. 

 Apical system subcentral or eccentric in front. 

 - Ambulacra subpetaloid, almost straight. 



Periproct supramarginal, transverse, surmounted by a more or less developed, 

 subrostrate roof. Peristome pentagonal, subcentral, or only slightly excentric, with 

 well-developed floscelle, the bourrelets being large and the phyllodes highly developed 

 and ornamented. Tubercles much larger on the actinal surface than on the 

 abactinal.^ 



There is much to be said in favour of the classification of Alexander Agassiz, 

 which places this group as a subgenus of the genus Cassidulus. "We retain it as a 

 genus provisionally ; for our ideas of classification develop themselves as this great series 

 of Echinoderms is gradually examined and described. 



1. Rhynchoptgus Caldeei, d'ArcUac & Eaime, sp. Plate XV, Figs. 1-4. 



Eurhodia Calderi, d'Archiac &[ Haime, Descrip. Anim. foss. dv, groupe Numm. de VInde, p. 352, pi. xxx. 

 fig. 19. 



A single example of a Cassidulid, which we refer to dArchiac and Haime's 

 species, is included in the collection of the Echinoidea of the Ranikot series. The 

 specimen is large but badly preserved, and, from not being found in place, doubt exists 

 as to the correctness of its being included in this series. It may have come in from a 

 higher horizon — probably the Khirthar. We have compared this fossil with a series 

 from that group, and find that the accordance both of the form of the test and also of 

 the matrix is exact. Still, as the doubt exists, we mention the species here, and give a 

 description of the imperfect specimen by which it is represented. A more complete 

 detail of structure will be given when we treat of the fossils of the Khirthar group, 

 which is probably the true horizon of the form. 



The test is elongate, ovoid in marginal outline, moderately high, and roof-shaped 

 above, rather sharply rounded in front, broader and rounded behind, except on either 



