460 New Species of Cladophyllia, Prionastraea, and Stylina. 



3. Stylina Collinsi, sp. n. 

 (From the Mexican Neocoraian.) 



Diagnosis. — Corallum massive ; irregularlj nodular ; broad 

 based ; taller than thick. 



Ccenenchyma variable in width from a mere film to a band 

 as wide as the corallites. The surface is either marked hy 

 the confluent costee or it is smooth or granular between raised 

 calicular margins. 



Septa thin, in 2 or 3 cycles. The symmetry is octameral. 



Columella stout, usually appearing as a well-raised knob. 



Dimensions. — 



Corallum 50 mm. thick by 60 mm. high by 90 mm. long. 



Diameter of corallites 1*5-2 mm. 



Average distance of calicinal centres . . 3-3'5 ,, 



Distribution. — Neocomian. From limestone half a mile 

 from the quicksilver mine at La Trinidad, 4 miles from the 

 town of Guadalcazar, State of San Luis Potosi, Mexico, 

 alt. 6500 feet. 



Collected by Mr. H. F. Collins, who has kindly presented 

 half of the specimen to the British Museum (Nat. Hist.). 



Fig. 3. 



f\\)f^%k.J^.:% 



Part of surface of the specimen with six caUces. x 6 diam. 



Affinities. — This coral is a member of the octameral group 

 of Stylina. Its nearest ally is Stylina pachystylina, Koby *, 

 from the Swiss Urgovian. In all probability the two corals 

 are geographical varieties, but with the available material it 

 is unsafe to identify them as the same species. The Mexican 



* Koby, Mon. Polyp. cr6t. Suisse, pt. i. 1896, p. 20, pi. v. fig. 6. 



