255 



Fig. 5. Young larva of Tripneustes gratilla (Linn.), 3 days old. Dorsal view. The skeleton 

 has been dissolved. ^^7i- 



6. Same as Fig. 5; side view, ^^"/i- s. c. suboral cavity. 



7. Larva probably belonging to Toxopneustes roseus (Ag.). Not yet fully formed. 

 Slightly distorte* Ventral view. i'°/i. 



8. Young larva of Toxopneustes pileolus (Lamk.), 9 days old. Ventral view. i*°/i- 



Plate IX. 



Fig. 1. Young larva of Strongylocentrotus franciscanus (A. Ag.), 4 days old. Dorsal view. 



2. Larva of same species, 8 days old; ventral view. ^^°/i- 



3. — — — 10 days old; side view. ^^Vi- 



4. Fully developed larva of Strongylocentrotus franciscanus, taken pelagically. Drawn 

 from a preserved specimen. The course of the ciliated band along the sides not 

 quite distinct in the specimen. ^^%. 



5. Larva of Strongylocentrotus pulcherrimus (A. Ag.), 4 weeks old. Ventral view. ^""/i. 



Figures 1 — 3 and 5 drawn from life. 



Plate X. 



Fig. 1. Young larva of Evechinus chloroticus (Val.), 14 days old. Ventral view. ^^"/j. 



2. More advanced larva of same species, 3 weeks old. Dorsal view, ""/i- 



3. Fully developed larva of same species; nearly 5 weeks old. Ventral view. '"/i. 

 4 — 5. Two abnormal young larvse of Evechinus chloroticus. '"/i- 



6. Nearly fully developed larva of Temnopleurus toreumaticus (Klein); ventral view. 

 9 days old. Drawn from life, ^""/i- 



7. Fully developed larva of Arachnoides placenta (L.), 7 days old. Ventral view, ^'"/i- 



Plate XI. 



Fig. 1. Young larva of Heliocidaris tuberculata (Lamk.), 6 days old. Dorsal view. ^^^/j. 



2. Fully formed larva of same species, 5 weeks old. Ventral view. In the posterior 

 end a pedicellaria has appeared; a muscle is seen connecting the lower ends of the 

 postoral rods. Drawn from life, ^^"/i- 



3. Larva of Temnopleurid, species c. Slightly restored. The true shape of the epaulets 

 not to be ascertained, ^^"/x- 



4. Larva of Echinobrissus {Oligopodia) recens (M. Edw.), 4 days old; ventral view, ^"^/i- 



5. Larva of same species, 10 days old; ventral view. ^°Vi- 



Plate XII. 



Fig. 1. Larva of Echinometra lucunter (Linn.), 7 days old; dorsal view. The body skeleton 

 has begun to be absorbed. Drawn from life. Showing the nervous system (the 

 oblique line on the anal area, at the base of the postoral arms), ""/i- 



2. Larva of Echinometra oblonga (Blv.), 12 days old; side view. Body skeleton partly 

 dissolved, ^"o/^. 



3. Larva of same species, same age; ventral view. The skeleton has been omitted 

 in the figure, being partly dissolved so that a correct drawing of it could not be 

 made. (Comp. fig. 2). ^""/i. 



4. Larva of Colobocentrotus atratus (Linn.), 12 days old; side view. ^""/i. 



5. Larva of same species, same age; ventral view. Skeleton dissolved. Drawing from 

 a preserved specimen, combined with a sketch from life. ^""/i. 



6. Young larva of Temnopleurus toreumaticus, 22 hours old; ventral view. The ciliated 

 band rather too distinct in the figure. ^^Vi- 



Plate XIII. 



Fig. 1. Echinopluteus transversus, species c. Ventral view. ^'■/j. 



2. — — — a. — — Slightly corrected, the postoral 



band having been shown in what is evidently its normal place, not in the place 

 where it is seen in the specimen, below the end of the ventral transverse rods. i*Vi. 



