Trof. P. Martin Duncan — On Galerites alhogaleni.s, Lamk. 13 



they appear to be closer, especially above (abactinally), and they 

 form a distinct row close to the edge of the poriferous zones. The 

 ambulacral plates are irregular and very unequal, and many of them 

 do not reach the centre of the ambulacrum ; but each has a pair of 

 pores which are simple and directly superposed on the upper 

 surface (abactinal), and being grouped in triplets lodged in oblique 

 furrows on the actinal surface. The apical system is compact, almost 

 square and granular. It is composed of four genital plates and a 

 small imperforate supplementary plate, and of five ocular plates all 

 perforated. The small posterior genital plate does not separate the 

 postei'ior ocular plates, which are very unequal in size and differ in 

 shape, the right posterior being in the median line. The anus 

 (periproct) is large, elliptical, infra-marginal, slightly pointed at its 

 upper end and with a long triangular area between it and the mouth. 

 Peristome central, rounded decagonal. The figures given on plate 

 47 of Cotteau and Triger's work noticed above are faulty as regards 

 the apical system. 



Loven employs the synonym Echinoconiis conicus, Breynius, for 

 Galerites alhogalerus, places the form amongst the toothed Echi- 

 noidea,^ and explains that there is no fifth generative plate. In his 

 plate XV. fig. 134, he indicates the large madreporic right anterior 

 genital plate stretching over the median line and uniting with the 

 much smaller left anterior and left posterior generative plates. He 

 shows that the right posterior ocular plate comes into the median 

 line, and has its anterior edge in contact with the madreporic plate, 

 and that the postero-lateral generative plates are separated by this 

 ocular plate alone. So that the posterior part of the madreporic 

 plate is in contact with the postero-lateral generative plate and the 

 right posterior ocular plate. 



The distance between the postero-lateral generative plates is not 

 great, and the edge of the ocular plate which is jammed in between 

 them is narrow from side to side. The madreporic does not pass 

 backwards beyond the postero-lateral generative plates. 



The position of the posterior ocular plates is remarkable ; the 

 right one being more anterior than the left, which is pushed behind 

 and to the left, and does not come in contact with the madreporic 

 plate. 



This able observer notices the deficiency of knowledge regarding 

 the interradial areas of the Echinoconida3, but notices the disposition 

 of the ambulacral pores near the peristome in triplets and gives an 

 admirable illustration of them in another species (op. cit. plate xiv. 

 fig. 129, page 20). 



" The Kevision of the Echini;' by A. Agassiz dates 1872—1874. It 

 does not describe the genus Galerites, but he states (p. 337) that he 

 "would limit the Galerites to the group provided with teeth. " I am 

 aware that the great development of Galerites in former geological 

 periods, and the relation of the anus and test (? mouth) may on 

 further acquaintance with living representatives entitle them to rank 



^ Loven, Etudes sur les Ecliinoidees, Stockholm, 1872. 



