ECHINOIDEA. 33 



expands at the lower end. The posterior zone becomes very quickly broad, but gets 

 narrower towards the end ; the pores are of very unequal size and show a remark- 

 able arrangement, inasmuch as the outer pores are placed obliquely with regard to 

 the inner ones; the narrow furrow by which they are joined forms therefore an 

 obtuse angle with its apex turned upwards. Their basal portion is very distinctly 

 marked, at the two anterior corners of the mouth, by a series of rather strong 

 tubercles surrounded by deep scrobicules which are perforated on the top. 



The postero-lateral ambulacra exhibit the same arrangement of the poriferous 

 zones, but they are much shorter ; their basal course is marked by two broad and 

 apparently smooth bands on the lower surface, which show a few isolated pores ; 

 near the mouth the pores are arranged in a similar way to those of the antero-lateral 

 ambulacra. 



The peristome is very close to the anterior border, but unquestionably larger 

 than that of H, pyrenaicus. 



Situation of anal opening unknown. 



Tubercles the same as in the previous two species, showing the same arrange- 

 ments, — viz.t the larger ones chiefly on the lower surface in two areas divided by 

 two, apparently smooth, bands, and two series of the same kind, on either side of the 

 aateal sulcus ; but whether the tubercles are really smaller than in the two preced- 

 ing species or not, I am unable to say. 



Locality and stratigrapMcal position. — Very rare in the Dunghan stage of Mr. 

 Oldham, Dds Valley. 



Memarka. — I identified this species with reluctance with Hubert's Semi' 

 pneustes leymeriei, but after a careful examination I came to the conclusion, that 

 it would be impossible to look upon the Baluchistan specimen as a different 

 species, although it is apparently much smaller than Hebert's specimen. On the 

 other hand, if we consider the shape of the test, particularly the profile of the 

 upper surface, the likeness is striking ; among all the known species of Eemi- 

 pneustes, it is only H. leymeriei that has the apex situated behind the centre. 



Besides the general shape there is the less marked anteal sulcus, but parti- 

 cularly the curious arrangement of the pores in the posterior zones of the lateral 

 ambulacra. Hebert states that only the pores of the posterior ambulacra diverge, 

 a feature, however, which is not well seen in his figure ; the specimen which I 

 examined shows that the anterior ambulacra also exhibit this feature, and, strange 

 to say, the right antero-lateral ambulacrum in a ;iiuch more marked way than the 

 left one. As the specimen shows distinct sighs of weathering, I am not quite certain 

 whether this feature is not perhaps a secondary one, being the result of a partial 

 superficial destruction of the plates of the poriferous zones. 



E. leymeriei for another reason is one of the most remarkable species of this 

 ffenus for although all the other forms show a considerable difference between 

 length and breadth, the measurements of both are nearly the same with this species ; 

 the ratio — is '95 to "98 in the specimens from the Pyrenees and '98 in the 

 Baluchistan specimen. 



