Miscellaneous. 497 



On two new Echinidesyrom Eastern Asia, 

 By Dr. E. von Martens. 



Amongst the Echinodermata collected during the Prussian Expe- 

 dition to the East the two following species possess a peculiar interest, 

 because they belong to genera of which numerous species are known 

 from former geological periods, whilst they are represented at present 

 only by single divergent species, or by none at all, according as the 

 boundaries of the genera are enlarged or narrowed. 



1. Scutellajaponica,n.sip. 

 Motsingai(i,e. "Kitchen-shell") of the Japanese Encyclopaedia. 



Rounded pentagonal, above slightly convex, beneath flat. Ambu- 

 lacral plates similar, nearly (but not completely) closed at the end, 

 occupying two-thirds of the distance from the centre to the margin ; 

 the pores of the same pair are wider apart in the middle of the plate 

 than at its central or peripheral extremity ; the furrows uniting the 

 pores of each pair are everywhere distinctly marked. From the end 

 of each ambulacral plate two diverging rows of three or four distant 

 single pores run towards the margin. The margin is rounded ; the 

 anal orifice is situated in the margin, directed a very little upwards. 

 The furrows of the lower surface divide within the first third of the 

 distance from the mouth to the margin into two branches, which 

 diverge at an angle of about 30°, and each of which again forks 

 twice or three times quite close to the margin. Four genital pores, 

 at equal distances from the centre, like the commencement of the 

 ambulacral plates. Upper surface densely granulated ; lower surface 

 set with rather larger tubercles, each of which is surrounded by an 

 impressed space. Colour dark violet above and below. Spines 

 short, cylindrical, of a silky lustre ; the lower ones longest (up to 

 2 mill.). In the interior, near the margin, from five to seven uniting 

 walls between the upper and lower walls. 



Diameter Q7y height 8 millimetres. 



Hab. Japan, in the Mississippi Bay within the Gulf of Jedo, 

 upon a shallow sandy bottom near the shore. Many specimens were 

 found. 



The figure cited in the Japanese Encyclopaedia represents the 

 ambulacral plates and the ventral furrows in a recognizable manner, 

 so that there is no doubt as to what it is meant for, although an 

 important character, namely, the position of the anal orifice, is not 

 represented. 



The present species constitutes an intermediate form between the 

 genera Scutellay Scaphechinus, and Echinarachnius ; it might be 

 regarded as forming a separate genus with as much right as the two 

 latter; but just this combination of characters counsels us rather to 

 diminish than to increase the number of genera. Scutella japonica 

 agrees in the position of the anal orifice with Echinarachnius (and 

 Scaphechinus) as opposed to Scutella, in the ramification of the 

 ventral furrows with Scutella and Scaphechinus as opposed to Echi- 

 narachnius, and, lastly, in the circumstance that the ambulacral 

 plates are situated in the same plane with the interambulacral spaces. 



