REPORT ON THE ECHINOTDEA MORTENSEIST 259 



[Not Cidarites annulifera Lamarck, Hist. nat. des animaux sans vertebres, 



vol. 2, 1816. 

 Not Stephanocidaris bispinosa A. Agassiz, Illustr. Cat. Mus. Comp. Zool. 

 No. 7, part 1 (Mem. Mus. Comp. Zool., vol. 3), 1872, p. 160; pt. 3, 

 1873, p. 393.] 



Localities. — Station 5144; in the vicinity of Jolo (Sulu) ; Jolo Light 

 bearing S. 50° W., 3.4 miles distant (lat. 6° 05' 00" N., long. 121° 

 02' 15" E.); 35 meters; coral sand; February 15, 1908 (1 specimen, 

 Cat. No. E. 1325, U.S.N.M.). 



vStation 5148; in the vicinity of Siasi, Jolo (Sulu) Archipelago; 

 Sirun Island (N.) bearing S. 80° W., 3.8 miles distant (lat. 5° 35' 

 40" N., long. 120° 47' 30" E.) ; 31 meters; coral sand; February 16, 

 1908 (2 specimens, Cat. No. E. 1343, U.S.N.M.). 



Station 5149; in the vicinity of Siasi; Sirun Island (W.) bearing 

 N. 39° E., 2.4 miles distant (lat. 5° 33' 00" N., long. 120° 42' 10" E.) ; 

 18 meters; coral and shells; February 18, 1908 (1 specimen, Cat. No. 

 E. 1341, U.S.N.M.). 



Station 5164; Tawi Tawi group, Jolo Archipelago; Observation 

 Island bearing S. 82° W., 8 miles distant (lat. 5° 01' 40" N., long. 119° 

 52' 20" E.); 33 meters; green mud; February 24, 1908 (1 specimen, 

 Cat. Nos. E. 1269, E. 1287, U.S.N.M.) . 



Notes. — The specimens from stations 5148 and 5149 are large, and 

 that from station 5164 is young; the specimen from station 5144 is 

 referable to var. chinensis Doderlein. 



Remarks. — The large specimens from stations 5148 and 5149 are 

 very interesting in showing that this species reaches a much larger 

 size than was hitherto known, up to 78 mm. in horizontal diameter. 

 These specimens have evidently reached their full size and with their 

 primaries overgrown with barnacles and other organisms, give the 

 impression of being very old. It is noteworthy that both the apical 

 system and the peristome of these specimens are relatively much 

 smaller than in medium-sized examples. Thus the apical system is 

 37.1-37.7 per cent of the horizontal diameter, as against 43-50 per 

 cent in medium-sized specimens, and the peristome is 28.2-29.2 per 

 cent of the horizontal diameter, as against about 34-45 per cent in 

 medium-sized examples. Evidently this signifies that the apical 

 system and the peristome cease growing some time before the growth 

 of the test ceases. In accordance with this, the number of peristo- 

 mial plates is not greater in these old specimens than in those of 

 medium size. 



Some of the primaries in the old specimens are distinctly flattened 

 in the outer part (pi. 52, fig. 3), just as is the case in large specimens 

 of Prionocidaris oaculosa, var. annulifera. Further, the large speci- 

 mens have the interporiferous zone of the ambulacra thickly set with 



