R. M' Andrew in the Gulf of Suez. 119 



Astropecten polyacanthus^ Miiller & Troschel, Syst. Aster, p. 69, 

 t. 5. f. 3; Dujard. & Hiipd, Echin. p. 417. 



Hob. Gulf of Suez (M^Andrew). B.M. 



Astropecten Hempi'ichii, Miiller & Trosch. Syst. Aster, p. 71 ; 

 Dujard. & Hup^, Echin. p. 419. 



Hah. Red Sea (Burton) ; Gulf of Suez (]\r Andrew). B.M. 



Genus Luidia, Forbes. 

 Hemicnemus, Miiller & Troschel. 



Luidia Savignvi, Gray, Ann. & Mag. N. H. 1840, vi. p. 183 \ 

 Miiller & Troschel, Syst. Ast. p. 77, 1842; Savigny, 

 Echin. Egypte, t. 3. f. 1 ; Hup^, p. 432. 



Asterias Savic/nii, Aud. Expl. 



Hab. Red Sea; Gulf of Suez (M' Andrew). B.M. 



Fani. CidaridsB, Gray. 

 Cidarides, Dujard. & Hup4, p. 468. 



Cidaris bacidosa, Lamk. A. s. V. ; Aud. Ill ; Savigny, Echin. 

 Egypte, t. 7. f. 1 ; Michelin, Mag. Zool. 1845, p. 18, t. 4. 

 f. 1-8 ; Dujard. & Hupt^, p. 471 ; Martens, Wiegm. Arch. 

 1866, p. 141. 

 Hab. Red Sea; Gulf of Suez (M' Andrew). B.M. 



The spines vary in form according to the age of the speci- 

 mens. In the young the spines are elongate, slender, fusi- 

 form, with the distal end attenuated to a more or less acute 

 tip, and the spines are twice or sometimes even more than 

 twice the length of the diameter of its body. 



In the older specimens the spines are nearly cylindrical, 

 scarcely attenuated at the end, which is often truncated ; they 

 are rarely longer than the diameter of the body : the spines 

 near the vent have the apex deeply and irregularly grooved ; 

 those nearer the mouth have the end truncated and more or 

 less dilated, with a more or less flat or concave end, which is 

 sometimes furnished on the margin with irregular lobes. 



The spines on the upper surface of the body are often en- 

 tirely covered with tufts of Jania or a thin crust of Lepralia ; 

 and some of them have one or more small parasitic Oysters 

 with a crenated and plicated margin affixed to them : such 

 parasitic growths were not present on the spines of any of the 

 other Echini in the collection. The spines on the underside, 

 especially those nearer the mouth, are clear, and show the 



