376 PROF. S. H. REYNOLDS AND DR. A. VATOHAN ON [Aug. IO, 1 1 , 



Occurrence. — At Burrington, and at other points of the South- 

 AYestern Province that have been carefully revised, Caninia patula, 

 in the mutation (?) that has no minor septa, is diagnostic of y. 



In Belgium the typical Caninia patula ranges to my personal 

 knowledge through C v but I have seen it nowhere else. (The 

 precise horizon of Dr. Salee's figured specimens is not stated.) 



It is possible that C. bristolensis Yaughan (= C. cylindrica, 

 mut. S x Yaughan) may be a member of the gens C. aff. patula as 

 suggested by Dr. Salee (op. cit. p. 33) ; C. bristolensis has, however, 

 the following very marked characters that ally it with 0. cylin- 

 drica mut. C , and distinguish it from C. patula : — 



(1) The septa are strongly developed only wit hi n the inner wall, and are 



all much thickened in the adult stage. 



(2) The prolongations of the septa through the vesicular area are very 



irregular in their course and very faintly developed, suggesting late 

 acquisition of the structure. 



(3) These prolongations are, in places, discontinuous ; and in such regions 



large vesicles are developed, resembling those of C. cylindrica. 



(4) The minor septa project inwards beyond the vesicular ring as short 



teeth thickened by stereoplasm, exactly as in C. cylindrica. 



(5) The vesicular ring is composed of an inner zone of fine, closely- packed 

 vesicles, and a broader outer zone of coarse irregular structure. 



In confirmation of his suggestion Dr. Salee remarks (p. 46, op. 

 cit.) that he has never observed, in any coral, the acquisition of 

 small vesicles following a stage characterized by large ones. This 

 contention is, however, definitely disproved in the case of Caninia 

 cylindrica mut. C , where the transition is clearly demonstrable (see 

 below, under C. cylindrica). 



Caninia cylindrica (Scouler) Salee. (PL XXXI, fig. 1.) 



A. Salee, 'Le Genre Caninia' Brussels 1910, pp. 27-39 & pis. ii-iv. 



Dr. Salee has given so excellent an account of this species, and 

 has illustrated it by such majestic figures, that I have contented 

 myself with a single figure snowing the highest stage of develop- 

 ment reached in C at Burrington — the only level, at that place, at 

 which the species is known with certainty. 



The earlier stages are exactly as figured by Dr. Salee in pi. iii of 

 his monograph, namely : — 



(1) A ' cornucopia ' stage — strong bilateral symmetry, no vesicles, short 



minor septa, pennant-like majors. 



(2) A ' cornu-bovis ' or amplexoid stage — short thickened majors and short 



minors, broad central tabular area, peripheral vesicles irregularly 

 developed at thickened rings and absent at constrictions. 



(3) 'cylindrica, mut. y ' stage— septa, both major and minor, prolonged 



outwards for a short distance from the inner wall so as to produce a 

 narrow 'external' area, beyond which they extend discontinuously as 

 projections from the large peripheral vesicles (see PI. XXXI, fig. 1). ; 



In C and later forms in other parts of the South- Western 

 Province, mutation proceeds simultaneously along two lines : — 



(a) The septal prolongations extend from inner to outer walls, traversing 



the whole vesicular area. 



(b) The fossula becomes diminishingly conspicuous, with the result that 



a Campopbylloid stage is acquired. 



