no 



ECHINOIDEA. I. 



peculiarities; triphyllous pedicellarise I have not seen. In the globiferous pedicellarise numerous 

 spicules are found, somewhat thickened in the ends (PI. XXI. Fig. 24. a), although not markedly dumb- 

 bell-shaped; also a few common bihamate spicules are found among them. In the tube feet the biha- 

 mate spicules are predominant, but the other form is also found. -- De Loriol, no doubt, is right 

 that this is a distinct species; but it is no Echinus. Its nearest relations are Echinus* verruculatus 

 and especially darnleyensis. 



Echinus darnleyensis Woods. Of this species I have had occasion to examine a specimen from 

 Thursday Island, Torres Strait, 4 fathoms (the Alert-Expedition) in British Museum. (I cannot 

 answer for the correctness of the determination; that it corresponds with the description is no guar- 

 antee for its being the same species, as the description gives only the usual things: spines, tubercles 

 etc., but mentions neither spicules nor pedicellarise.) A primary tubercle is found on every ambulacral 

 plate; according to Woods (442. p. 165) the ocular plates are quite shut off from the periproct - but 

 according to an information from Prof. Bell they are not shut off from the periproct in these speci- 

 mens (I have forgotten to ascertain it myself). The buccal membrane is quite naked with the excep- 

 tion of the buccal plates which are placed in pairs opposite to each other, and carry a few pedicellariae. 

 With ten rounded small openings surrounded by Pedicellariae , it is said in the description by Woods; 

 this, I think, must be the holes in the buccal plates for the buccal tube feet --a rather common 

 feature to note in a description of species! Innermost in the edge of the mouth numerous needle- 

 shaped, more or less irregular spicules are found resembling those of EcA.- Robillardi; they are 

 arranged parallel to the edge of the mouth; a few are a little fenestrated. Outside of these some 

 bihamate spicules are found, but far from so great a number as in Robillardi. Near the gills numerous 

 bihamate spicules are found in the buccal membrane. The gills themselves contain the common irre- 

 gular fenestrated plates. According to Woods the auriculae are only slight thin processes, which do 

 not meet; Prof. Bell informs me that they are here of the common form. (In verruculatus and Robil- 

 lardi they are also of the common form.) The globiferous pedicellarise as in Spharechinus , only is 

 the blade uncommonly short (PL XXI. Fig. 36). In the tridentate pedicellarise (PI. XXI. Fig. 7) the blade 

 is broad, open, with only a slight net of meshes in the bottom. The edge is finely, simply serrate in 

 the outer part where the valves join; in the lower part a few larger indentations are found. The 

 valves are rather wide apart. Ophicephalous and triphyllous pedicellarise of the common form. The 

 spicules (PI. XXI. Fig. 23) of the globiferous pedicellarise arcuate, but not pointed at the ends ; in the 

 tube feet only a few bihamate spicules are found. -- Woods thinks that it is this species Agassiz 

 has wrongly referred to Ech. magcllanicus; that it has nothing to do with magellanicus is certain, 

 although the differences pointed out by Woods: in the actinostome being larger; in the abactinal 

 system, where the genital plates have only two tubercles, and in the color of spines and test are 

 quite irrelevant. The principal difference is to be found in the globiferous pedicellarise and the spi- 

 cules; they show that this species is uo Echinus or Sterechinus at all, but like Ech. Robillardi and 

 verruculatus is closely allied to Toxopneustes and Tripneustes. 



To the genus Toxopneustes Ag. are referred the species: maculatus (Lamk.), pileolus (Lamk.), 

 elegans Doderl., variegatus (Lamk.), and semituberculatus (Val.); to the genus Tripneustes Ag. (in Rev. 

 of Ech. this genus is called Hipponoe] are referred the species: esculentus (Leske), dcprcssus Ag., and 



