182 R. GOTO ; 



much llattencd and almost spatulato in the inner, but much 

 longer and slender in the outer part (PI. IV, Tig. 75). The whole 

 series may contain from 5 to 10 spines in all, of which the 

 outermost 3-5 are long and slender. These spines, but especially 

 the marginal longer ones, are attached close to the distal border of 

 the inferomarginals, and are generally closely appressed to the next 

 distal plate, so that the spiny character of the inferomarginals is 

 not so apparent as in some other species, when the animal is viewed 

 as a whole. This series of spines is more distinct than in Astrop. 

 scoparius and Astrop. polyaccmtlius, owing to the fact that they are 

 more regularly arranged and better differentiated from the general 

 armature of the inferomarginals. The general surface of the latter is 

 covered with comparatvely large and flat scales. There is a series 

 of small cylindrical spinelets along the margins of each plate. 



Adamhulacrah. — In the greater part of the arms there are 

 three adambulacrals to every two inferomarginals. The first ad- 

 ambulacrals are very narrow and the surface of each plate is for 

 the greater part divided into two ridges separated from each 

 other by a narrow longitudinal groove (PJ. IV, fig. 74). The 

 spines, which are of equal length and short, are arranged regular- 

 ly in two rows corresponding to the two ridges, and only in the 

 outermost portion, where the crest is single, is there a slight 

 tendency to an irregular arrangement. There are from a dozen 

 to about twenty-five spines in each series, according to the size 

 of the specimen (PI. IV, fig. 73). 



From about the fourth adambulacrals on there are, on each 

 plate, three thick, somewhat flattened, prismatic truncated spines 

 of nearly equal length on the inner border, then follow, separated by 

 a rather conspicuous space, two or three spines arranged almost in 



