104 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



the corallites have distinct, raised rims. The septal and costal characters are the 

 same as in A. speciosa, and the corallum is very light. 



One of the Wilkes Exploring Expedition specimens, to which no name was 

 attached by Dana, is precisely intermediate between A. speciosa and A. puteohna. 

 It is represented by plate 36, figures 2 and la. 



Regarding Astreea pandanus of Dana, plate 36, figures 4, \a, plate 37, figure 1, 

 are three views of the type (No. 36, U. S. National Museum), and sufficiently illus- 

 trate the growth-form and general character of the calices. I he tollowing is a 

 description of it: 



Greater diameter of the calices ranges from 6.5 to 10 mm.; the lesser diameter from 

 6 to 8 mm. Margins elevated. Costa? prominent, thin, with dentate edges. 



Septa thin; usually 12 to 14, sometimes 16, reach the columella; in the interseptal 

 loculi between the longer septa there is commonly one shorter septum, sometimes there are 

 2 or 3 intermediate shorter septa and occasionally there is none. Margins with rather long 

 dentations over the arch, both inside and outside the wall, and within the calice to the 

 boundary of the columellar fossa, where the inner edges of the principal septa have a more 

 or less developed paliform tooth and then drop perpendicularly to the periphery of the 

 columella. Teeth faint on the vertical part of the margin. 



Columella weakly developed. Exotheca and endotheca greatly developed, very 

 vesicular. 



Besides Dana's type there are in the U. S. National Museum 17 specimens 

 collected by J. B. Steere in the southern Philippines, some of which almost duplicate 

 the type. Among the striking characters are the light corallum and the relatively 

 small number of septa which reach the columella. The principal difference between 

 A. pandanus and A. speciosa consists in the larger number of septa which reach the 

 columella in the latter. Matthai appears to have included both under one species, 

 to which he applies the untenable name clouei, 1 but he is correct in considering them 

 as belonging to one species. 



Astreea fragilis Dana is another variant of the same species. It is represented 

 by plate 37, figure 2. The calices in this are more crowded and average smaller 

 than in A. pandanus, but some are 10 mm. long; width from 4 to 8 mm. 



The U. S. National Museum contains a splendid suite of this species. Besides 

 the 22 specimens discussed in the preceding remarks, there are 16 more from the 

 Philippine Islands, 1 from Djibouti (French Somaliland), 1 from Fanning Island, 

 collected by Mr. Carl Elschner, and 2 which will now be considered. 



Dr. Mayer collected on Murray Island a single specimen (plate 37, fig. 3), which 

 has calices up to 11.5 mm. in diameter, 11 mm. usual, and 7 to 8 mm. deep. Fis- 

 sion is more frequently unequal than equal. The skeletal structures are somewhat 

 thicker than is usual in specimens from other localities, as would be expected in a 

 shallow, near-shore specimen, and the columella is slightly larger than the usual 

 average. 



Station, Murray Island. — Southeast reef, line I, 600 feet from shore; depth 

 of water, 15 inches; bottom, sandy. 



Dr. Wood Jones has brought from Cocos-Keeling Islands a specimen (see 

 plate 37, figs. 4, \a) on which he remarks: 



"This is a fragment of a boulder mass of 'floating coral.' The mass from which it 

 was taken was a large one, at least 3 feet in diameter, which was washed up on the sea- 

 ward shore of Pulu Tikus. No living coral like it was found in the atoll. Other smaller 

 masses of floating coral were found around the atoll, generally tossed high on the beaches 

 by the waves, all much sea-worn and rounded outwardly." 



'Op. cit., p. 89. 



