16/J SILURIAN RADIATA. 



Cystiphyllum brevilamellatum (M'Coy). 



Sp. Char. Corallum elongate, sub cylindrical, preserving for se- 

 veral inches a diameter of little more than an inch, slightly 

 tortuous, and with obscure, irregular swellings of intermittent 

 growth ; outer wall extremely thin, strongly ribbed with alter- 

 nately larger and smaller vertical lamellar sulci, about four 

 large and three smaller in the space of 3 lines, at the diameter 

 of 1 inch (or eighty- four all round) ; terminal cup with a cir- 

 cular depressed centre, equaling rather less than half the dia- 

 meter, surrounded by an inclined outer area composed of 

 twenty-four radiating lamellae (corresponding to the stronger 

 external sulci) extending from the walls about one-fifth of the 

 diameter, connected by close numerous transverse vesicular 

 plates, having at the margin an equal number of extremely 

 short lamellse (corresponding with the smaller external ridges) ; 

 internal area broad, formed of large vesicular plates irregularly 

 arranged : vertical section composed of arched, irregular, vesi- 

 cular plates, curving gradually from the walls under the cen- 

 tre, small and numerous at the sides, considerably larger in 

 the middle. 



It is possible that Mr. Lonsdale^s second figure of Cystiphyllum 

 Siluriense, t. 16 bis, f. 2, may be a young group of this species, 

 as this figure by its narrow form, radiated cups, &c. seems totally 

 distinct from his fig. 1, which is the true type of his species ; — 

 a new specific name would be required for it in any case. 



Wenlock limestone of Wenlock. 



{Col. University of Cambridge.) 



Caninia lata (M'Coy). 



Sp. Char. Young corallum very widely conic, attaining the adult 

 diameter of 3 inches at a height of about 2 inches, after which 

 it remains cylindrical for a height of several inches, marked 

 with irregular concentric obtuse undulations and small fim- 

 briated lines of growth ; in the young the radiating lamellse 

 are alternately longer and shorter, but before reaching the 

 adult diameter, they are all thin and nearly equal, four or five 

 in a space of 3 lines at a diameter of 2 inches 9 lines (or 110 

 to 116 all round), connected by numerous transverse curved 

 vesicular plates ; inner area formed of broad horizontal simple 

 diaphragms, which at a diameter of an inch extend almost 

 across the corallum to the exclusion of the outer vesicular and 

 radiated layer ; at a diameter of 2^ to 3 inches they maintain 

 a diameter of about an inch, the outer lamellated and vesicular 

 zone having proportionately increased ; each of the diaphragms 

 is strongly bent downwards at one point of the circumference. 



