IOS ECHINOIDEA. I. 



with trois paires de pores obliques . Now if the two authors had done so consciously, they would 

 certainly have made a remark to the effect that the type specimen had not the six pairs of pores, but 

 only three. Such a remark, as far as I can see, they have not made, and so there can scarcely be 

 any doubt that this species has quite wrongly got the name of microtuberculatus. As a synonym of 

 it Agassiz & Desor (loc. cit.) mention Ech. pulchellus Ag. and decoratus Ag., and the former of these 

 names should then be employed for this species. The description of Ech. pulchellus 1 ) may agree rather 

 well with it, even if it cannot be said to be a very appropriate one; it might also agree with young 

 specimens of Strongyloc. lividus. Therefore I think it better to wait for a renewed examination of the 

 type specimens, before the commonly used name of microtuberculatus is rejected. 



Ech. angulosus is distinguished from the two other species by the two ocular plates reaching 

 to the periproct, and by the plates of the buccal membrane being fine and quite imbedded in the skin; 

 only a few are thick and carry pedicellarke. The globiferous pedicellarise have only two, more rarely 

 three teeth on either side; the tridentate ones are more strongly sinuate in the outer part where the 

 valves join (PI. XVII. Fig. 6); the larger ones have a rather strong net of meshes, the edge is thick, 

 in the lower part with very distinct transverse series of small teeth. The ophicephalous pedicellarise 

 have generally only a simple keel in the middle of the blade, without any net of meshes 

 (PI. XVII. Fig. 3). 



These three species must absolutely form a separate genus. Most recent authors use the name 

 of Psammechinus Ag. for them, but wrongly. In Catalogue raisonne p. 64 under the fourth type 

 Sous-genre Psammechinus Ag.> are named first the species variegatus Lamk. and scniitubcrculatus 

 Val. and as no. 3 subangulosus Lamk. There can be no doubt, then, that the two first-named may 

 claim the name of Psammechinus, as it appears that they cannot be classed with the genus Toxo- 

 pneustes, to which they are referred in Rev. of Ech. , but must form a separate genus (see below). 

 For the species miliaria, microtuberculatus, and angulosus a new genus must then be established; I 

 propose the name of Parechinus. 



Psammechinus verruculatus Ltk. Agassiz (Rev. of Ech. p. 122) mentions this species as syno- 

 nymous with Parech. angulosus; de Loriol (245. p. 21) objects to this and maintains that they are two 

 well distinguished species. I must not only grant that de Loriol is right in his statement, but shall 

 have to go much farther and assert that it cannot be referred to the same genus, nay, not even to 

 the same family as Parech. angulosus. Prof, de Loriol has kindly sent me a specimen of his 

 Echinus verruculatus Ltk. from Mauritius, and so I have been able to compare it with the type 

 specimens of L ii t k e n , which are found in the museum of Copenhagen. All the type specimens are 

 naked tests, so that it is impossible to tell quite certainly, whether the species of de Loriol is really 

 identical with these specimens; all the most important characters are wanting on the naked tests — 

 nay, it is, moreover, probable that the type specimens really belong to two different species. It is, 

 however, certain, that the description given by de Loriol of the coloration of his specimens 2 ), agrees 

 exactly with two of the type specimens, and I think it very likely that they are really identical. Full 



M Introduction to Valentin's Anatomie du genre Echinus, p. VI. 



2 ) In the specimen sent me by de Loriol, there is no trace of coloration on the test; only the spines have the 

 colour described by de Loriol. 



