OF WESTERN SIND. 41 



join. The distinction from Dictyopleurus d'Archiaci is, that in the variety there is a 

 vertical line of raised tissue in the interradium on either side, connecting the vertical 

 row of tubercles together. The test is very thick ; and the transverse depressions over 

 the sutures are deep and much broader than high. There are no pits in the test at 

 the sutural angles. 



3. DiCTTOPLEUEus d'Akchiaci, sp. nov. Plate X, Figs. 5-8. 



The test is small, conico-turban-shaped, swollen at the ambitus, and sloping 

 gradually to the apex with a gentle curve. The actinal part is rather flat but slightly 

 convex, and the actinostome is sunken and small. The apical system is deficient. 



The ambulacra are narrow, the poriferous zone slightly sunken ; and the pores are 

 in simple vertical series, and about three to each interradial plate ; they are on slight 

 ridges. The interporiferous zone has a ribbed ornamentation which crosses it, leaving 

 rather irregularly-shaped depressions on either side of the median line ; these are deep, 

 square, or irregularly oval and triangular spaces, and are largest above the ambitus. 

 There are also transverse linear depressions ; the number of plates is considerable, and the 

 ridges on them are of different lengths. A vertical row of small primaries is on either 

 side just within the poriferous zone ; and the tubercles are raised on the ridges, have a 

 tumid boss and a small mamelon ; they are faintly crenulated. A close ornamenta- 

 tion of large miliaries, some of which are very distinct, covers the ribs of the ornamenta- 

 tion. The interradial areas are marked with well-developed ornamented transverse 

 ridges leaving rectangular furrows between them, whose transverse continuity is 

 arrested by the primary tubercles. The ridges are broad and high ; moreover they 

 project well from the test; they are rectangular, have their actinal edges slightly wavy, 

 and are ornamented by three transverse rows of well-developed miliaries. Each one 

 is connected with the ambulacral poriferous plates by a narrow short ridge, and with 

 its fellow, on the opposite side of the median line, by a very short process from each 

 upper and actinal angle. There are two vertical rows of primary tubercles on the 

 interradial areas, and a primary is thus situated in the midst and towards the actinal 

 edge of the ornamented ridge. It is large for the dimensions of the plate, is sur- 

 rounded by a linear scrobicular circle, and has a tumid boss and a small mamelon. 

 Crenulation and perforation exist. The actinal edge of the tubercle impinges on the 

 plate below ; but no vertical ridge is observed in the perfect form. 

 Height of specimen \ inch, breadth -^g inch. 



Locality. Hills east of Lynyan, from brown limestones. Ranikot series. Survey- 

 number G fff. 



The specimen which has been taken as the type has been weathered, except close 

 to the supporting piece of rock, and the furrows over the lines of the sutures are very 

 distinctly shown. In the ambulacra, the larger plates which supported the primary 

 tubercles are projecting, and there is a vertical ridge between the raised ridges of the 

 interradial areas in relation to the primary tubercles. 



Another specimen, which has been well weathered, shows these points more 

 distinctly, and is delineated on Plate X, Figs. 7 & 8. 



