Narrative of Bahama Expedition. 169 



bearing a half globe of pedicellaria'. on their upper surfaces. 

 At the bases of these last are ver\' large sessile pedicellaria'. 

 These specimens were about four inches in diameter, and 

 came from a depth of seventy to eighty fathoms. 



A species belonging to the PentagonastJ':rid.-e agrees in 

 almost every detail with the unusually complete description 

 given by Sladen for the genus Lcptoo'oiiastcr, although it also 

 agrees superficially with the figure given of Aiit/icuoidcs 

 p/crcci ( Perrier) secured In" the Blake. Our specimen has 

 no pedicellaria' on the dorsal surface; the disk is large; the 

 arms taper gradually to a slender point; the upper surface 

 is covered with polygonal plates, between which numerous 

 papula? appear; there is a well marked ridge on the supero- 

 marginal plates; the infero-marginal plates are armed on their 

 external edges with a row of spines; the actinal surface is 

 covered with granulated plates; the interambulacral plates are 

 armed with fan-shaped groups of spines, immediately outside 

 of which is another series of larger and stouter spines, and 

 outside of these a row of very large, procumbent pedicellaria?; 

 diameter about five inches; depth eighty fathoms. 



One of the most noticeable things about the Opiiiurid.^: 

 was their tendency to appear in great quantities of individuals 

 belonging to a single species, as if they lived in definite spots 

 of the sea bottom which were densely crowded with certain 

 species to the exclusion of others. Professor x\lexander Agas- 

 siz has noted this peculiarity of the fauna of the Pourtales 

 Plateau, and his observation was amply confirmed by our ex- 

 perience, more particularly in connection v\'ith the serpent- 

 stars. The number of species was not very great, but the 

 individuals were in surprising cpiantities. The most extensive 

 colony of any one species of Ophiuran that the writer has ever 

 seen was not here, however, but in the Bay of Fundy, where 

 in dredging the channel between two islands, the dredge came 

 up time after time tilled to the top with OphiopJwlis. hcllis 

 Lym. and a species of coralline. 



Among the Opiiiurid.e or serpent-stars, probabh- the most 

 abundant species was a small white Ophioi^lyfha. with the disk 



