112 



ECHINOIDEA. I. 



otherwise quite brown), there is another faet that raa}', perhaps, be of some significance. In T.pilcoliis 

 the secondary tubercles in the arabulacral areas — on the piates wanting the primary tubercle — are 

 as large as the primary ones, so that it can only be seen from their position, whether they are prim- 

 ary or secondary ones; in rosnis the primary tnbercles are distinctly larger than the secondary ones 

 on the piates where the primary tnbercle is wanting. If this feature proves to be constant, there can 

 scarcely be any doubt that they are two well distinguished species. In spicules and pedicellariæ any 

 difference of importance is scarceh' to be foiind. 



Toxopneustes elegans Doderl. agrees exacth' with T. pileolns (I have not, however, seen the tri- 

 dentate and triphyllous pedicellariæ); as far as I can see it is only distinguished from T. pileolns by 

 its peculiarly coloured spines — they have a sharply limited dark band near the point — and by the 

 colour of the test, it being in T. rlegai/s yellowish without any indication of coloration, only the median 

 suture of the ambulacral and interambulacral areas is dark violet on the apical side. (Doder- 

 lein 114. p. 99.) 



Toxopneustes varicgatiis (Lamk.). To the e.xisting descriptions I shall add the foUowing 

 remarks. A primary tubercle is found on all the ambulacral piates. The globiferous pedicellariæ 

 (PI. XXI. Figs. 38, 40) with tubular blade, without lateral teeth, not very much lengthened. Glands 

 may be found on the stalk, but are most frequently wanting. The tridentate pedicellariæ (PI. XXI. 

 Fig. 10) are large, the head up to i"5""", and long-necked. There is only little mesh-work in the blade, 

 the edge is straight, rather thick, with numerous, irregularly placed small teeth; the valves are only 

 a little apart below. The triphyllous and ophicephalous pedicellariæ of the common form. The 

 spiciiles (PI. XX. Fig. 15) are dumb-bell-shaped, exceedingly numerous in the skin of the globiferous 

 pedicellariæ (as in all these species); here all transitional forms may be found from small, oval bodies 

 to typical, bihamate spicules (PI. XXI. Fig. 31), but the really dumb-bell-shaped ones are by far themost 

 numerous. In the tube feet only bihamate spicules are found in small number. 



Toxopneustes semitiiberculatus (Val.), no doubt, is most nearly allied to T. variegatus\ especially 

 must be emphasized that it likewise has a primary tubercle on all the ambulacral piates. Spicules and 

 pedicellariæ as in T. variegatus^ only the globiferous pedicellariæ show a conspicuous peculiarit\- the 

 lime in the valves being of a deep violet colour, with the exception of a small, oblong, clear spot in 

 the basal j^art on either side of the apophysis. Glands are found on the stalk. — Otherwise , as is 

 well known, it is distinguished from variegatns by the less marked plate-covering on the buccal 

 membrane. 



Tripneustcs csculentus (Leske). A primår)- tubercle is only found on every third or fourth 

 ambulacral plate. The buccal membrane contains numerous small fenestrated piates inside of the 

 buccal piates, outside of these fewer, small, round, thick piates with pedicellariæ are found. The pedi- 

 cellariæ are mimerous, much pigmented, and form a quite black ground between the spines. The 

 globiferous pedicellariæ are small, the valves as in the other allied forms (PL XXI. Fig. 39). Glands 

 are found on the stalk. In the tridentate pedicellariæ (PI. XXI. Fig. 16) the blade is filled by a highly 

 developed net of meshes; the point rather abrupth- widened with the edge exceedingly finely serrate, 

 in the lower part of the blade the edge is more or less coarsely dentate. The valves are rather wide 

 apart, only joining at the point. Together with these a smaller form of tridentate pedicellariæ 



