142 MADREPORARIA. 



P. Bnrhtda ? (PI. II. fig. 9). The tendency to flakiiiess is not sufficient to obliterate 



the trabecuhir pattern. 

 1\ Florida 1. The tiakiness is e.xtreme, but the rings of round iioles sliow the inter- 



septal loculi, and other spaces, e.g. those between pali and central tubercle, 



indicate the normal Porites pattern disguised. 

 /'. IVesf, Indies x. i7(ri. V. fig. 6). The wall elements are melted down into smooth 



irregular masses, like flakes. 



D. The " astrjeoid" group. The names " astrwoides" and " astrseoid " occur very frequently 

 in this Volume, and it is necessary to be explicit as to the sense in which I intend them to be 

 understood, wherever they are used in these pages. The first term has been inherited, as the 

 name of an imaginary species (see the Historical Sketch, p 3). Our attempts to explore 

 this species have resulted in the recognition of the following facts : (1) that so far as growth- 

 form is concerned, we can no longer speak of an astrceoides group, meaning thereby some 

 special type of growth, for the term seems to cover any form not branching ; but (2) inasmuch 

 as the species " astrceoides " was intended for massive and exjilanate forms characterised by a 

 certain type of calicle, it is legitimate to apply the name " astraioid " to that type of calicle, since 

 it has a distinct character of its own. The astrieoid calicle then is one in which the pali 

 remain undeveloped in the base of a large deep open fossa, its visible wall is formed by the 

 wall ring, with an occasional appearance as well of the ring joining tlie septal granules, at least 

 in cases where the walls thicken. But the typical calicle of this group shows only the wall- 

 ring, the inner synapticular wall remaining deep down. 



P. Guadalupe 6 (PI. II. fig. 2). The septa are smooth, sharp, frequently irregularly 

 thickened by traces of septal trabeculre. Fig. 3 shows a portion of the same, 

 when the walls are proliferated into a flaky reticulum, cf. G. 



P. Antigua 4 (Fl. II. fig. 7). The septa are blunt and sometimes knobbed. 



* P. Barbuda 3 (I'l. III. fig. 1). The calicles vary in depth ; where shallow the 



skeleton appears somewhat solid though perforated by nearly symmetrical rings 

 of round pores, showing the typical structures. 



• J'. Anguilla 2 (i'l. III. fig. 3). The calicles vary in depth ; the skeletal elements 



are rough, and with great irregularity of internal arrangement. 



P. St. I'homas 5 (PI. III. figs. G and la). The septa are long, somewhat straggling, 

 and thin, but not specially sharp-pointed ; occasional pali and central tubercles 

 visible. In fig. 7a, the septa and skeletal elements generally are slightly 

 thicker. Fig. 76 is of the astrreoid Porites called " incerta " by Duchassaing 

 and Michelotti ; while the skeleton of the walls is thicker, the septa are shorter 

 and taper to sharper pomts. 



P. Belize 3 (PI. I. fig. 6). The septa are very short and very sharp, but the elements 

 are all continuous, that is show no breaking up, cf. P. West Indies x. "iiS. 



P. Belize. S (PI. I. fig. 7). Tile septa join with reticulum ; columeUar tangle high 

 up in the fossa. 



P. Florida G (PI. IV. fig. 1). The septa not sharp but knobbed ; columellar tangle 

 or plate not far down. 



* These forms, with the "columella laxa," woidd ajipiireiitly iiiivo l)L'eii called Co^wojH„i/es by 

 Duchassaing and Michelotti ; see above, p. 7. 



