ASTEROIDEA OE H.M.S. ' CHALLENGER ' EXPEDITION. 247 



two irregular series of smaller and subconically shaped spinelets, 

 about three standing at irregular distances next to the inner 

 spinelets, and about five in the outer series. Owing to the irre- 

 gularity of Dumber and position and their tendency to group, 

 these outer spinelets do not form the definite continuous lineal 

 series presented by the inner or furrow-series of ambulacral 

 spinelets. 



Mouth-plates large, and the combined pairs form conspicuous 

 tubercular prominences. The median suture is imperfectly closed 

 and expands at the aboral extremity of the plates, exposing the 

 odontophore. Along the free horizontal margin of the plate 

 range a series of 6 or 7 mouth-spines similar to the ambulacral 

 spines, the innermost being slightly largest. The surface of the 

 plate bears a number of spiniform granules, which are most 

 robust and elongate on the adoral half of the plate. Beyond 

 this these appendages do not appear to present any special 

 arrangement or to form definite series ; and they impart a very 

 echinulate aspect to the mouth-angles. 



The ventral interbrachial areas are large and covered with 

 membrane and minute, subspiniform, conical granules ; these 

 are small, very numerous and rather closely placed, and dis- 

 tributed over the whole area, here and there with a faint ap- 

 pearance of grouping, which seems to suggest the indication of 

 the separate ventral plates. Of the actual outline, arrangement 

 or character of these plates no observations can be made, owing 

 to the uniform and thick covering of membrane with which they 

 are overlaid. 



Colour, in alcohol, yellowish white, the paxillar area having a 

 rather browner shade. 



Station 89. Lat. 22° 18' N., long. 22° 2' W. Depth 2400 fms.; 

 bottom temperature 1°'8 C. ; Globigerina-oozQ. 



Family Asteopecthstid^. 



ASTEOPECTEN, LmcJc. 



Synopsis of Species herein enumerated. 



A. With two series of definite spines on the supero-mar- 

 ginal plates, 

 t Three marginal spines, Ambulacral spines, three 

 in the inner series, and three also in second series, 

 the aboral largest brasiliensis. 



