60 T. M. DTJN'CAN' ON THE ECHINODERMATA OE THE 



poriform body, and then passes across the line of the posterior lateral 

 ambulacra, turning forwards in the inter ambulacral space and being 

 visible thence to about mid way bet ween the apical system and the am- 

 bitus in front (PL IV. fig. 8). The fasciole then crosses the ridges 

 on either side of the odd ambulacrum and completes the circuit. 

 The band of small granules constituting the fasciole is narrow, but 

 very distinct ; but the anterior transverse portion is not very marked. 

 The cavity for the odd ambulacrum is moderately deep, and has on 

 either side towards the apical system a ridge which is ornamented 

 with numerous small tubercles encircled by miliaries. The abor- 

 tion of the anterior poriferous zones of the antero-lateral ambulacra 

 is evidently in relation to the presence of the internal fasciole. Our 

 knowledge of the subanal spectacle-shaped fasciole (PI. IY. fig. 6), 

 first noticed by Laube, and subsequently by Mr. Etheridge, may be 

 thus added to : — It commences in a mass of miliaries on the sub- 

 anal plates, and then passes outwards and curves downwards. The 

 union is made with that of the other side by a narrow transverse 

 line of granules, which, as a fasciole, passes across the intervening 

 space. The curved upper part of the fasciole on either side is, in 

 some specimens, prolonged inwards so as to incompletely include a 

 space which is ornamented with small tubercles, the scrobicules of 

 which are separated by ridges. These tubercles have the mamelon 

 very distinct ; and in their neighbourhood are smaller ones in more 

 or less definite rows, and some in a part of a circle bounding the 

 fasciole internally. 



The outer curve of this fasciole (on either side) is within the 

 range of the posterior lateral ambulacrum, the plates of which, as 

 they are continued to the ambitus, pass down beneath the ornamen- 

 tation of the outer part of the fasciole and the outer part of the 

 included space. It results that there are five or six pores in these 

 plates which appear within the fasciole (Plate IV. fig. 6), in a 

 semicircle just on its inner edge. They are distinct in worn speci- 

 mens, and can usually be distinguished in others close to the tubercles. 

 The periproct may be round, ovoid, or elongated transversely ; and 

 the subanal space may be high or low in the same variety of the 

 species ; but in all, the ornamentation of the subanal space is very 

 distinct, and consists of miliaries and a few very small tubercles. 



The peristome has the posterior lip edged with a ridge of plain 

 ornament ; and behind this are rows of small miliaries succeeded by 

 larger ones whose numbers become less and less. The posterior lip 

 is bent downwards ; and the anterior and lateral parts of the peri- 

 stome pass upwards into the funnel-shaped cavity, which is semi- 

 lunar transversely. 



The floscelle is tolerably well developed ; and the pores are dis- 

 tinct and belong to all the ambulacra, the anterior odd ambulacrum 

 being nearly destitute of them ; but it presents two pores on 

 either side and the relics of the sphaeridial space. A very beautiful 

 ornamentation is seen around the floscelle, in front especially ; and 

 it includes that of the larger first polygonal peristomial plate (inter- 

 radial). This is slightly convex and has pretty miliaries on it. 

 Distinct but small tubercles with flat scrobicules are in and around 



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