626 MR J. W. GREGORY ON THE MALTESE FOSSIL ECHINOfDEA. 



Sarsella anteroalta, n. sp. PL II. figs. 7 and 8. 



Diagnosis. — Form elliptical, but with the anterior margin flattened, and but slightly 

 furrowed by the anterior ambulacrum. The test is depressed, with a thin margin 

 posteriorly ; at the anterior end it is tumid, and the whole of the anterior ambulacrum is 

 upon a broad raised area. The highest point is in front of the apical system. The 

 posterior interradius is somewhat carinate. 



Ambulacra : The anterior is in a broad shallow groove upon the top of a raised area. 

 In addition to the adjoining interradii, parts of the anterolateral ambulacra take part in 

 the formation of this raised area. The paired ambulacra are in broad shallow depressions ; 

 in the front pair the anterior poriferous zone is very short, as the pores are not continued 

 up the steep, almost vertical wall of the raised area. The posterior pair also terminate 

 abruptly against the fasciole. 



Apical system : Four large genital pores ; ethmolysian ; the madreporite is continued 

 far behind the posterior pores. 



Fascioles : The internal fasciole is broad and distinct ; it crosses the anterior ambu- 

 lacrum at about a third of the length of this from the anterior margin ; it is continued 

 back on the upper part of the sides of the raised area, and extends for some distance 

 behind the apical system, the two halves meeting at an acute angle on the posterior 

 interradius. The details of the subanal are not discernible. 



Anus on the thin posterior margin. 



Epistroma : A few large tubercles, with deep scrobicules, occur in the antero-lateral 

 interradii, and in the extreme anterior corner of the posterior pair. 



Dimensions — 



Length, ...... 



Width, ...... 



Height, ...... 



Distance of apical system from anterior margin, 

 Antero-lateral ambulacra : number of pores in anterior zone, 



„ „ „ posterior „ 



Postero-lateral „ „ „ anterior „ 



ii „ >, », posterior „ 



Type.— Brit. Mus., E. 3420, 3421. 



Distribution. — Malta — Globigerina Limestone ; bed b at Dueira. 



Remarks. — This species may be readily distinguished from any other Sarsella by the 

 depressed condition of the ambulacra, a character especially marked in the youngest 

 specimens. If the division into Spatangidse and Brissidae be accepted, including in the 

 former those with flush and in the latter those with depressed petals, then a new genus 

 must be created for this species. But in all other respects it is a true Sarsella, and it is 

 here allowed to remain in this genus ; the reasons for this have been already stated on 



B. M., 



E. 3420. 



E. 3421. 



26 



mm. 



30 mm. 



24 



»> 



28 „ 



6 



»> 



8 ,, 



11 



n 



13 „ 



5 





7 



9 





11 



9 





10 



10 





11 



\ 



