ECHINOIDEA. II. 



the pyramid (5) of the odd posterior interambulacrum being considerably larger than the others. (Comp. 

 Loven. Echinologica. p. 69). 



The spines are a little longer than in pusillus, the largest being ca. i ram , and more slender. 

 They are provided with only a few serrations and end in rather a slender point. (PI. XII. Fig. 15.) The 

 miliary spines are only about one third as long as the primary ones. They are a little slenderer than 

 those of pusillus, often slightly serrate near the upper end. The endcrown is a little larger than in 

 pusilhis; the longitudinal ribs are more widened at their upper end, almost joining with their edges, 

 and the radial plates are larger and broader, generally with 4 5 serrations, sometimes in a double 

 series. (PI. XII. Figs. 10, 16). - - The pedicellarise also differ rather considerably from those of pusillus. 

 The ophicephalous pedicellariat differ from those of pusillus in having fewer serrations along the edge 

 of the blade, otherwise the shape and structure is the same as in that species. (PI. XII. Figs. 8, n 13). 

 The tridentate pedicellariae (PI. XII. Figs. 25, 28) are gradually narrowed towards the articular surface, 

 whereas in pusilhis they narrow abruptly at the lower end of the blade. The triphyllous pedicellarise 

 (PL XII, Fig. 21) have a much broader blade than in pusillus, and the edge is much more closely ser- 

 rate; they are very small, the head only ca. O'O4 mm . - The buccal tube-feet are not distinctly larger 

 than the other actinal tube-feet. Spicules are wanting as in pusillus. 



To this species so well distinguished by its large ocular pores, little developed petals, few 

 actinal pores, as well as by its spines and pedicellariae, belong all the specimens of ; Echinocyamus 

 pusillus* from the Blake and Albatross which I have seen (viz. from Blake St. 5 and 239, 

 Albatross St. 2352, 2666 and 2668), as well as the specimens from the Challenger St 122 (examined 

 in the British Museum); a pair of specimens dredged by myself in 500 fathoms off Frederiksted, St. 

 Cruz, also belong to this species. Probably all the specimens of Echinocyamus recorded from the West 

 Indies and Florida (and Brazil) under the name of pusillus will turn out to belong to this species 

 (and perhaps partly to the following species). In any case the existence of Ech. pusillus in these 

 regions must remain doubtful, until by renewed careful examination it is proved beyond doubt to 

 exist there besides Echinocyamus grandiporus. I have further seen rather numerous specimens of this 

 species from the Azores from depths of ca. 100 700 fathoms (1365 m.) and from the Josephine Bank 

 (no 430 fathoms). 



The occurrence of this species on both sides of the Atlantic is in good harmony with the dis- 

 tribution of other Echinoids, e. g. Genocidaris maculata, Cidaris affinis a. o. and likewise it would 

 not be contrary to these facts of geographical distribution, if Ech. pusillus should turn out to occur 

 in the West Indian Seas; it must only be emphasized that it cannot be considered as an established 

 fact, before the specimens of grandiporus (and possibly also of macrostomus] are distinguished from the 

 true pusillus by renewed examination. 



Echinocyamus macrostomus n. sp. The shape of the test (PI. XII. Figs. 17, 24) is very like 

 that of grandiporus, a little more elongated, but not so much that it can be relied upon as a specific 

 character. The peristome is generally very large; there is, however, some variation in this respect, 

 but I have always found it considerably larger than in specimens of grandiporus of a corresponding 

 size. The edge of the peristome is not incurved; the buccal membrane is devoid of spicules as in the 

 other species. The anal opening is generally larger and nearer the edge of the test than in grandi- 



