1880.] PROF. F. J. BELL ON THE TEM NOPLEURIDiE. 433 



(a) The specimens with a number of primary tubercles in a 

 transverse row (Plate XLI. figs. 1, 7). 



The test is pretty thick ; the poriferous zones are narrow ; the 

 acthiostome is of moderate size, and sunken ; the actinal cuts are 

 very shallow and wide. The test is grey or light brown ; the pori- 

 ferous zones and the median space of the iuterambulacral area may 

 be of a yellowish hue. At the ambitus there are, in the inter- 

 ambulacral area, six or seven tubercles on either side of the middle 

 line. In the ambulacral area there are three tubercles on each plate ; 

 all these tubercles are of very much the same size ; they decrease in 

 number as they pass to the actinal and abactinal poles : but they are 

 more closely packed on the actinal surface ; for there there is no bare 

 median space ; there, too, the plates are not quite so wide, and they 

 are not separated from one another by any sutural furrows. The upper 

 portion of the plate is occupied by a fairly regular row of miHaries, 

 The auricles are exceedingly strong and high, as are, too, the con- 

 necting ridges ; the foramen is not as high as the ridge, and is 

 triangular. I can give no information regarding the abactinal or 

 anal areas. 



Two specimens measured in diameter 67 millims. ; one was 30 

 and the other 33 millims. high ; the actinostome of either measured 

 18 millims. across ; the smallest of the three specimens was 58 

 millims. in diameter, 40 in height, and had the actinostome 17 

 millims. broad. 



None of the specimens has any known history or locality. 

 (ft) Specimens with one vertical row of primary tubercles above 

 the ambitus (Plate XLI. figs. 2, 3, 8). 



Test not quite so thick as in (a) ; the actinostome somewhat 

 smaller, and the cuts deeper ; it is not quite so sunken ; the pori- 

 ferous zone wider ; the pores frequently have on their outer edge 

 tubercles, and do not, therefore, occupy a completely marginal posi- 

 tion on the ambulacral plates. 



At the ambitus there is only one large primary tubercle on either 

 iuterambulacral plate ; this is rather nearer the outer than the 

 inner edge of the plate ; and on either side of it there are two or 

 three distinct secondaries. On the actinal surface there are four, 

 three, or two tubercles, large, and of much the same size, on every 

 iuterambulacral plate ; below the ambitus in the ambulacral area 

 there are two rows of primary tubercles ; and from the ambitus to 

 the actinostome two rows, gradually decreasing in size, are inter- 

 calated between these ; above the ambitus the outer rows, which are 

 continued to the abactinal pole, decrease at first rapidly in size. 

 The other rows are likewise continued some way up the side of the 

 test ; but the tubercles diminish so much in size that they are with 

 difficulty to be distiiiguished from the miliaries. 



The anus is large, the genital rings narrow, the madreporite not 

 much larger than the other genital plates ; the ocular plates are 

 excluded from the anal area. The auricles are very well developed, 

 but the connecting ridges are rather low ; the foramen is a little 

 larger than in the form just described, is triangular, and is just 



