108 PEOr. p. M. dttncan's reyision of the 



the sutures often or not with regular deep portions, and the pits 

 deep at the angles, or sutures deep and plain. Tubercles plain 

 or indistinctly crenulated. Knobs and sockets of the dowelling 

 few in comparison with Temnopleurus. 



Fossil. Tertiary : Java. 



Mecent. Japan ; Arafura Sea. 



The genus OpecTiinus, Desor, 1858, Synopsis, p. 107, has several 

 shallow pits in each transverse coronal suture, and its author 

 considers that there are recent and fossil species ; amongst the 

 first he instances none, but probably meant to refer to Pleur- 

 echinus ; in enumerating and describing the fossil forms he mentions 

 the so-called Temnopleuri of the Nummulitic of Sind. It has been 

 shown (Duncan & Sladen, Pal. Ind. ser. xiv., Foss. Ech. of Sind, 

 1882, pt. ii. p. 36, and same series Ech. Kachh & Katty war, 1883, 

 p. 54) that the forms described by d'Archiac and Haime were 

 not from the Nummulitic, but from the higher Tertiaries, and 

 that they could not be separated from Temnechinus, Eorbes. But 

 it is quite evident that several of the TemnecMni, when rolled 

 and weathered, show several shallow pits along the transverse 

 sutures. All the specimens seen by d'Archiac and Haime were 

 in a most wretched condition, and are still in the museum of tlie 

 Greological Society of London. 



We do not consider that Opechinus is a good genus. 



Genus Tejotechinus, Forles, 1852, Pal. Soc, Monogr. Brit. Tert. 

 Ech. p. 5. Desor, 1858, Sptoj^sis, p. 105. A. Agassiz, 1872- 

 74, Bevision, p. 285; 1883, ^ BlaJce' Bchin. p. 37. Duncan 

 Sf Sladen, 1883, Pal. Ind. ser. ziv., EcJi. of KachJv Sfc. p. 57. 



Syn. OpecMiius, Desor. 



Small or moderate-sized tests, subglobular, depressed abac- 

 tinally. Epistroma moderate. 



Apical system prominent, sutures between the plates more or 

 less grooved; a large periproctal plate and a few small anal 

 ones *. 



Ambulacra with a slightly undulatiag series of pairs of pores ; 

 pairs in triplets, the middle pair in a demi-plate, the adoral com- 

 ponent a large primary, the aboral component a smaller primary; 

 two vertical rows of small plain primaries in the interporiferous 

 area. Interradia with primaries resembling those of the ambu- 

 lacra but larger ; some secondaries. Transverse sutures of 



* This refers to T. maculatus, A. Ag., the recent species. 



