vaughan: madreporaria. 63 



Desmophyllum galapagense, sp. nor. 



Plate 1, figs. 1-lb. 



Corallum curved, attached by an expanded base ; transverse outline of calice, 

 elliptical. 



Measurements : height, -15 ram. ; diameter immediately above basal expansion, 

 2.5 mm. ; greater diameter of calice, 6.75 mm., lesser, 6 mm. 



The corallum wall is very thin, its outside is polished and glossy, but shows 

 minute transverse lines of growth that are parallel to dentations on its upper edge 

 which correspond in position with the septa. 



Septa thin, in four complete cycles, primaries and secondaries of equal size, with 

 exsert margins, about 1.5 mm., tertiaries shorter, quaternaries still smaller and may 

 be rudimentary. The septal faces granulated, granulations small, showing arrange- 

 ment parallel to the septal margin and also in linear series. 



Calicular fossa very deep and narrow. No columella. 



Locality : — Station 4642, southeast face of Galapagos Islands, 5 miles from 

 southeast end of Hood Island ; depth, 300 fms. ; bottom, broken shells and 

 Globigerina; temperature of the bottom, 48.6° F. The specimen grew 

 attached to Madrepora galapagensis, sp. nov. 



Remarks: — Desmophyllum galapagense is close to D. alabastrum Alcock, but 

 the latter species has the third and fourth cycles of septa buried "in the 

 depths of the cup where at first they escape notice." It is very close to 

 D. eburneum Moseley, and may ultimately be combined with that species, it 

 differs from the latter, however, by the entire absence of costae, and none of 

 the primary septa bend outward beyond the margin of the calice. 



Madrepora galapagensis, sp. nov. 



Plate 1, fig. 2 ; plate 2, figs. 1-lb. 



Corallum in its basal portion thick and compact ; branches anastomosing. The 

 colonies evidently attain considerable size. The terminal branchlets are stout, 

 rather short, with thick bases. One branchlet measures 20 mm. in length, 7 mm. 

 in diameter at the base, terminal calice 4.5 mm. in diameter. Some branchlets are 

 shorter, others are longer, and the terminal calice may not have so great a diam- 

 eter, but the branchlets are constantly relatively thick. 



The calices on the branches are usually dichotomous in arrangement, occasionally 

 there is opposite gemmation in a plane at right angles to the plane passing through 

 the middle of the dichotomous calices. On the older portions of the corallum the 

 coenenchyma is very highly developed and there is no definite calicular arrange- 

 ment. 



The fully developed terminal calices are about 4.5 mm. tall, and about 4 mm. 

 in diameter measured between the thecal summits ; 4.5 mm. is probably the max- 

 imum calicular diameter on a branchlet. On the basal portion of the corallum the 

 calices are as much as 10 mm. apart, and range in diameter from 2.5 to 3.5 mm. in 

 diameter. They are deep, even exceeding 3 mm. The elevation of the calicular 



