286 ECHINOSPATAGUS 



The base is flat and partially covered, and the position of neither the mouth-opening 

 nor the vent is shown. 



Affinities and Differences. — It certainly resembles some specimens of Toxaster 

 complanatus, but differs from all in the form of the test, being as broad as it is long ; its 

 greatest transverse diameter is about the middle of the test. From this point the 

 anterior portion of the ambitus maintains its rounded outline, whilst the posterior 

 portion rapidly contracts to form the narrow truncated posterior border. 



The pairs of petaloidal ambulacra are lodged in depressions of the test, whilst they 

 are quite on the general surface without depressions in T. complanatus. The conical 

 elevated portion of the upper part of the posterior border is likewise very different from 

 the broadly truncated posterior border in T. complanatus. For these reasons I have 

 grouped it with the Fchinospatagi, and dedicated the species to Professor E. Renevier, of 

 Lausanne, who collected the specimen at Shanklin, Isle of Wight, and gave it to our 

 mutual friend Monsieur De Loriol, to whose cabinet it belongs. 



Locality and Stratigraphical Position. — Found in the inferior beds of Lower Green- 

 sand at Shanklin, Isle of Wight, in the hard grey sandy rock with numerous oolitic 

 grains of silicate of iron, and which contains fine specimens of Gryphcea sinuata and 

 Ostrea carinata, with the Echinides Clypeopygus Fittoni, Wr., and Enallaster Fittoni, 

 Forb. It is, therefore, derived from one of the richest Urchin-beds of the Neocomian 

 series in the Isle of Wight. 



Echinospatagus Quenstedtii, Wright, nov. sp. PL LXXV, fig. 2. 



Diagnosis. — Test cordate. Upper surface convex, very much declined, length and 

 breadth nearly equal. Ambulacral pairs unequal, lodged in shallow depressions. 

 Anterior pair lanceolate, not flexed ; form an angle of 40°. Posterior pair short ; form 

 an angle of 45°. The poriferous zones of both pairs equal. Ambulacrum long, anteal 

 sulcus shallow, poriferous zones not longer than the anterior pair, only grooving the 

 anterior border very little. Ambulacral summit excentral, situate at the junction of the 

 posterior with the middle third. Posterior border truncated concavely. Flanks sloped 

 inwards. Base small, flat ; mouth-opening transversely oblong near the ambitus. Vent 

 high up in the border ; periprocte oblong ; upper point extending to the beak-like process 

 of the test. 



Dimensions. — Length 2 inches and 1 tenth ; breadth 2 inches and 2 tenths ; height 

 at vertex 1 inch and 2 tenths. 



Description. — This Urchin was collected from the fine sandy calcareo-micaceous beds 

 of Lower Chalk or Upper Greensand in Wiltshire ; it is always more or less completely- 

 denuded of the plates of its test, and is found in the form of moulds. The fineness of 



