A. E. Verrill—The Bermuda Islands; Coral Reefs. 223 
Young specimens of this and the other species of Mussa are 
simple, circular, cup-shaped corals, usually up to half an inch or more 
in diameter (fig. 77), and have been described by many writers* as 
distinct species of another genus (Lithophyllia or Scolymia). But 
all stages of transition between these simple forms and the complex 
cealicles of the adults can easily be found at Bermuda + 
It is very variable in general form and in the size and form of 
the calicles and the intervening ridges, which may be simple or 
double, and in the form and breadth of the septa. The denticles of 
the larger septa are nearly always numerous and slender, often look- 
ing like sharp lacerations of the thin septa, but they vary consider- 
ably in form and number. 
Duchassaing and Michelotti made several species out of ordinary 
variations of this one, and Quelch followed them in this respect, but 
as their species could not be identified by their brief and imperfect 
descriptions, his names were often erroneously applied. To Dr. 
Vaughan I am greatly indebted for an excellent series of photo- 
graphs made for him from their original types, which are still pre- 
served in the Museum of Turin.f 
Their Symphyllia conferta and S. anemone agree very closely 
with Dana’s type of fragilis. Their type of thomastana is nearly a 
typical fragilis, but many of the calicles had been badly injured 
before death. The types of 8S. cylindrica and S. guadalupensis are, 
without doubt, abnormal or diseased specimens of the same species or 
of MW. dipsacea. In these the septa and their denticles have become 
unnaturally thickened by pathological deposits of calcium carbonate 
in nearly all the calicles. But some of the-younger marginal cali- 
cles, which remain partially or wholly normal, show the ordinary 
characters of dipsacea rather than of fragilis. 
Their S. verrucosa is the same as their guadalupensis. In the type 
* Quelch, Voy. Challenger, xvi, has recorded Lithophyllia cubensis and L. 
lacera from Bermuda; both are young of Mussa. 
+ See these Trans., xi, plates xvi-xix, 1901. 
+ Dr. T. Wayland Vaughan, when in Turin in 1897, was kindly permitted by 
Prof. Camerano to study the types of the species of Symphyllie described by 
Duchassaing and Michelotti. Count M. G. Peracca, who has charge of the 
Herpetological Collections at the Turin Museum of Natural History, very cour- 
teously made a series of photographic negatives, illustrating each one of the 
species whose type had been preserved. The United States Geological Survey 
had a number of duplicate prints made and these were distributed by Dr. 
Vaughan to various museums. Dr. Vaughan has given me permission to use 
them in making the revisions of the species described in this paper. 
