92 



found in the regular Kchiiii at once excludes bolh Ihe Spalangoids, the 

 Clypcaslroids and the Ciilarids, the Iwo iornier having quite another 

 type of ophicephalous pedicellarise, the latter being entirely devoid of that 

 type of pedicellaria\ Reviewing the regular Kchini. other than Cid- 

 arids, occurring in the West Indies, it seemed evident that Echinometra 

 luciinier was the only form that could come into consideration, taking 

 for granted that only littoral forms could come into regard when seeking 

 for the parental origin of these larva% which were found to occur in fairly 

 good numbers in the littoral waters. The premises were apparently quite 

 correct. Nevertheless the conclusion was wrong. It is not the larva of 

 FA-hinomelra lucunter: that larva, reared from the egg through metamor- 

 phosis, as described and figured in the present work (p. 71; PI. I, Figs. 

 1 — 2) has quite the typical shape of Echinoid larvae. — There was at that 

 time also some uncertainty regarding the larva of Diadema anlillunim, 

 it being only from inference concluded that the Diaderna-larxn would be 

 found to resemble Ihc luhinophileiis Mulleri, viz. that larva from the 

 Mediterranean which has been, though without sufficient evidence, 

 referred to Centioslephaniis loru/ispirnis, a near relative of Diadema. Al- 

 though the development of Diadema is still only incompletely known, the 

 shape of the young larva, reared by the present author (see above, j). 25 

 Pl.V, Fig. 5) gives sufficient evidence that it has nothing 

 with the Echinopluteus transversus to do, and Diadema is 

 then also really out of question as the parent of this larva. 

 There must therefore be something wrong in the premises, 

 either so that the type of ophiee])halous pedicellaria^ found 

 in the larva may be found also in other forms than the 

 regular Echini, save the Cidarids, or that the larvae may 

 Fig. 37. Ophice- belong to deep-sea fomis. Regarding the latter eventuality 

 phaious pedicel- I would say that — although it can scarcely l)e doubted 

 lana oi Echmo- ^^ ^^^^ deep-sea Echinoids have true pelagic 



pluteus transver- -' ' i o 



sits, species e. larvae — the fact that two species of this larval type were 

 "^"/i- found near the island of Taboga in the inner part of the 



Gulf of Panama, very far from the deep sea, decidedly speaks against the 

 suggestion that the larvae might belong to deep-sea forms. 



The ophicephalous pedicellariae (Fig. 37) are decidedly of the type 

 known to occur only in the regular Echinoids. Of these Arbaria, Diadema, 

 Tripneusles, Lijiechinus and Echinometra are all excluded, their larvae 

 being known more or less completely. The fact that there are two species 

 of larva? from the (iulf of Panama very closely related to two other species 

 from the Westindies would seem to preclude the idea of hiking forms like 

 Salenia, Coelopleurus, Podocidaris, or any of the Echinothurids or the 



