of the Jurnsair liri/ozori. 227 



/). Stovmtopora intermedin (Miinst.). 

 Aulopora intermedia, Miinster, 1831, in Goldfuss, Petref. Oorin. HI. i. 



p. 218, pi. IXV. fi;r. 1. 



Sfnmato/>ora intermedia, Broiin, 1849, Ind. Pal. p. 1202. 

 Alecto inti-rini-dia, d'Orbigiiy, ISoO, Prod. Pal. t. ii. p. 2'>. 



Diagnosis. — Zoarium formin<5 a crowded network. 

 ZiKi'cia cylindrical, very short. 

 Peristomes raised and much thickened. 

 Distribution. — Coralliaii, France and Germany. 



Synopsis of Species. 



I. Zocecia regularly tubular. 



Peristomes well raised ; zooecia short dichotoma. 



Peri.^toines slightly raised ; zooecia long Waltoni. 



Peri.*tomes thickened intermedia. 



II. Zocecia pyriforui dichotomoiden. 



III. Zooecia hippothoiform Smithi. 



111. Relations of the Jurassic Species. 



The four main characters used in the diagnosis of these 

 species are as follows : — The elevation of the peristome {p) ; 

 the shape of the zooecia (c) ; the size, and especially the 

 length, of the zocecia (/) ; and, last and least, the arrange- 

 ment of tiie zoarium (r). In order to sliow the relations of 

 these Jurassic species to those of later periods formula are 

 very convenient. Each of the characters may be represented 

 by a letter, and numbers adopted for the principal variations. 



Thus, let ]t stand for peristome ; if it is flush it may be 

 indicated by 0, if well raised by 2, and if slightly so by 1. 



In the subjoined forraulse the signs denote as follows : — 



