W. D. Lang — On Stomatopora antiqua. 261 



mais les individus auxquels elles donnenfc naissance s'ecartent 

 notablement I'un de I'autre. Eatre une bifurcation et celle qui la 

 suit, on compte ordinairement deux ou trois peristomes en serie. La 

 partie rampante des testules est mediocrement allongee, legerement 

 <!onique a I'origine, puis cylindroide et faiblement aplatie ; elle 

 presente des plis fins et d'autres plus prononces ; les pores sont 

 petits et assez ecartes. La grande largeur des testules depasse un 

 peu ^ de millemetre. 



" (Je fossile rappelle tout a fait par son aspect general la *S^. dichotoma ; 

 mais les irregularites que nous venons d'indiquer dans le mode de 

 multiplication, ainsi que la forme legerement conique des testules, 

 Ten distinguent suffisamment. Ces testules sont d'un autre cote 

 beaucoup moins longues et moins lisses que dans la S. Waltoni. 



"Tous les exemplaires que j'ai observes etaient fixes sur Gryphees 

 arquees, et ont ete decouverts par M. Terquem dans le lias inferieur 

 de Valiere (Moselle)." 



It will be seen that Haime expressly indicates " les irregularites 

 dans le mode de multiplication" — the pre-Jurassic trait of this 

 species; also that branching after Type II is exhibited, the 

 "deux testules jumelles .... restent presque completement 

 accolees I'une a I'autre." But the most important fact is not given, 

 namely, the point in the life-history of the colony when Type II 

 makes its appearance. 



The folding table (Table I) ^ of observations on nineteen zoaria 

 will give some idea of the limits of variation in this species. The 

 numbers in the first column are those of the dichotomies at which the 

 observation is taken, starting at the proximal end. The columns are 

 headed by the letters B.M. D., followed by two numbers. The letters 

 and the first number stand for the British Museum register number 

 of the specimen, the second number for that of the zoarium on that 

 specimen. In the first eight examples the first dichotomy was seen, 

 so the numbers of the dichotomies are known. In the last eleven, 

 divided from the first eight by a double vertical line, the proximal 

 €nd of the zoarium was wanting, and so the first dichotomy shown 

 was observed as x, the second as a; -|- 1, etc. But by comparison with 

 the first eight, the value of x was surmised. For an explanation of 

 the whole scheme I can only refer to my former paper.- The 

 abbreviations used in the table are as follows : — 



I, II. = branching after Tj'pe I, Type II. 



i. = branching after the Intermediate type. 

 s. = slightly. 

 V. = very. 

 180°, 90°, etc. = branches diverging at an angle of 180°, 90°, etc. 

 cyl. = cylindrical, 

 pyr. = pyriform. 

 sm. = smooth, 

 r. = ribbed. 



In Haime's figure the zooecia are as a whole shorter than in the 

 Tomes specimens, but there is very little difference ; and, as has 

 already been shown, partly owing to the irregular branching, the 

 length varies considerably. 



1 Folding Table I to be inserted to face this page. - W. D. Lang: loc. cit. 



