456 ADDITIONAL NOTES 



Heterocidaris Wickense, Wrigld, nov. sp. Supplement, PI. XLIIT, fig. 5 a, b, c. 



The only portions of this urchin I have seen were some fragments I found in the 

 collection of my friend, Mr. Leckenby, of Scarborough, and which were collected from a 

 sandy bed of Inferior Oolite at Blue Wick, near Robin Hood's Bay, on the Yorkshire 

 coast. The fragment figured consists of four plates (fig. 5 a), representing one half of 

 an inter-ambulacral area. There are three rows of large, equal-sized tubercles on 

 each plate, which are perforated ; the bosses are prominent, and their summits deeply 

 crenulated (fig. 5 c) ; the narrow areolae are surrounded by a circle of small granules ; 

 other granules are likewise sparsely scattered over the intermediate surface of the plates. 

 This is the urchin which Professor Phillips refers to in his work on ' The Geology of 

 Yorkshire/ of which he figures a single tubercle (pi. xi, fig. 2), and catalogues, at page 

 155, as a Cidaris from the Dogger of Blue Wick. 



The only Heterocidaris known to M. Cotteau was obtained by M. Triger from the 

 Inferior Oolite of Chevain (Sarthe). This magnificent specimen [Heterocidaris Tric/eri, 

 Cot.) has been figured in the ' Bulletin de la Societe Geologique de Prance,' 2nie serie, 

 t. xvii, p. 378, pi. iv, and likewise in the 'Echinides du departement de la Sarthe,' 

 pi, Ivi. M. Babeau has collected a fragment of another test from the Inferior Oolite of 

 the environs of the Langres (Haute-Marne), from a rock which contained Cidaris s^inosa 

 and C. Courtandina. 



Pseudodiadema lobatum, Wright, nov. sp. PL XLI, fig. 3 a, b, Supplement. 



Test depressed ; ambulacral areas narrow ; inter- ambulacra wide, with two prominent 

 rows of primary tubercles ; spines long, smooth, and pin-shaped ; neck, ring, and head 

 covered with fine, longitudinal lines ; stem smooth and uniform in thickness, tapering only 

 near the point. 



Dimensions. — Indeterminate. 



Description. — This small urchin was found at Pinhay Bay, near Lyme Regis, in a 

 thin band of marl appertaining to the zone of Ammonites planorhis. All the specimens 

 I have hitherto seen are so imperfect that they are insufficient for drawing up 

 a complete diagnosis of the species. 



The ambulacral areas are narrow, but as all the specimens I have seen are unfortunately 

 fractured through this region, the number and size of the tubercles thereon cannot be 

 examined. 



The inter-ambulacral areas are wide and well-developed, possessing two rows of 

 large, primary, perforated tubercles, raised on prominent bosses, with deeply crenulated 

 summits J they are surrounded by wide areolas, bounded by a defined margin, and 

 encircled with microscopic tubercles, which impart an ornamented character to the test. 



