ECHINOIDEA. II. 6l 



forniing the anterior etlge (posterior series of the antero-lateral interambulacra) are rather closely 

 covered bv primary tubercles, not arranged in distinct series. (Coiiip. Loven. Pourtalesia. PL I. 3). Tlie 

 miliary tubercles are generally ver\- numerons, especialh' on the anterior end of the test. — One speci- 

 nien is interesting in showing in considerable nnniber the empt\- piaces of primary tubercles; the 

 piaces are distincth- seen, but covered with pigmented skin, and it looks as if miliary spines have 

 appeared in sonie of theni. As mentioned above (sub Urccliiinis narcsiaiius, p. 41) Agassiz thinks 

 such cases a proof of the spines liaving been rcsorbed — I think it more probable that it is the result 

 of some damage iindergone by the speciraen. 



The primary spines are of a rather uniform length, the longest of them (the posterior ones of 

 those on the anterior series of piates of the antero-lateral ambulacra, in accordance with the size of 

 the tubercles) scarcely reaching one third of the length of the te.st. They are slightly curved, generally 

 smooth, ending in a simple point. Those of the sternuni are somewhat flattened, widened at the point. 

 The spines on the invaginated portion are short and very robust (Loven. Pourtalesia. PL V. 36); those 

 near the edge are longer and more slender, gracefully curved. The miliar\- spines are widened at the 

 point and curved, as figured by Wyv. Thomson (Pl.LXX. 8); the clavuke of the fasciole essentially 

 as the miliary spines, the widened point only a little shorter and thicker. 



vSpicules are almost totalh' wanting; sometimes, however, a very few irregular, branched rods 

 occur at the outer end of the tube-feet. The tip of the tube-feet, on the contrary, is enclosed b>- a 

 rather thick cap (or broad ring) of calcareons network (PL VII. Fig. 21); this holds good, however, only 

 for those of the antero-lateral ambulacra, which are, upon the whole, rather well developed. In those 

 of the odd anterior ambulacrum such a calcareons cap is generall}- not fonnd; sometimes a few irreg- 

 ular spicules occur there, but mostly they are quite destitute of spiculcs. 



Of pedicellariæ two kinds, viz. ophicephalous and tridentate, were described and figured by 

 Wyv. Thomson, and two kinds, viz. ophicephalous and rostrate ( laternenfdrmige tridentate) by D6- 

 derlein (Echinoiden d. deutschen Tiefsee-Exped. p. 269). I have fonnd these three forms; globiferous 

 pedicellariæ do not seem to occur. The rostrate pedicellariæ (PL XI. Fig.s. 9— 10, 30) are rather conspicuous 

 and numerons; the head up to ca. 0-5™'", more or less dark pigmented. They are generaUy threevalved, 

 but two- and fourvalved specimens occur. (For the description of the valves, comp. Doderlein, loc. 

 cit.) The elegantly shaped ophicephalous pedicellariæ are likewLse well described by Doderlein, 

 whilst Wyv. Thomson has given a pair of rather good figures of them; I give here only figures 

 of i.solated valves in front and .side view (PL XI. Figs. 4, 7). — It may be noticed that the narrow part 

 of the valves of these pedicellariæ contains a small irregular cavity, which opens into the deepening 

 in the widened outer part. This is, otherwise, especialh' distinct on the ophicephalous pedicellaria of 

 Pourt. paradoxa figured PL XI. Figs. 3, 6. I have not fonnd the ophicephalous pedicellariæ on all the 

 specimen.s. — The tridentate pedicellariæ, the form figured by Wyv. Thomson Pl.LXX. F'ig. 10, are 

 very .small, with a short but distinct neck. The valves (PL XI. Fig. 8) are simply leafshaped, the edge 

 of the outer part rather coarsely serrate. (That this form must be regarded as a tridentate, not a tri- 

 phyllous pedicellaria becomes evident from what is found in Pourt. hispida (comp. below p. 78); also 

 in Plexecliinits hirsiUiis a quite similar tridentate pedicellaria occurs together with typical triphyllous 

 pedicellariæ; comj^. above p. 56.) 



