BAMFORD— PELAGIC ACTINIARIAN LARViE 405 



The ectoderm is thin and compact, so thin indeed that the nematocysts with close 

 spiral threads, which alone ai-e present, are placed obliquely ; mucous gland cells ai-e 

 abundant. The stomodseal ectoderm is thick with numerous granular glands but no 

 nematocysts, and the filaments are similar but with long narrow nematocysts. The 

 structureless lamella is thicker than the ectoderm and also than the endoderm, which 

 is peculiarly thin. 



Loc. Three miles N.W. of Desroches Atoll, 100 fathoms. 



Larva with Twenty Mesenteries. (PL 24, fig. 23.) 



13. A single translucent, almost spherical larva, 1"5 mm. long by r2 mm. in 

 diameter, with a deep depression on one side to which sponge spicules adhere, has 

 12 complete and 8 rudimentary mesenteries. The stomodseum is very short. Longi- 

 tudinal muscles are present on some of the complete mesenteries. Filaments occur on all 

 except the couple next to one of the directive pairs ; they are shortest on the directives 

 opposite to the pair mentioned above, but all stop some distance above the 

 aboral end. 



The ectoderm is a comparatively thick layer of vacuolated tissue with scattered 

 nematocysts of a long and narrow form with somewhat irregularly and loosely coiled 

 threads ; a second large kind of nematocyst is found and granular glands are present. 

 The ectoderm of the stomoda3um is dense with the first kind of nematocysts and granular 

 glands ; it is continuous on the sides of the mesenteries and forms the filaments which 

 have spirally-threaded nematocysts. 



Loc. Lat. 3° 31' S., long. 72° 27' E., north of the Chagos Archipelago, 100 fathoms. 



