Homes or Tuhis furmul hij Auncliils. 1) 



'riii.s spccios has a series of pii^meut-specks (rudiineiitary 

 eyes) luuk-r the oral frill, ami even a motion of the hand will 

 cause retraction. 



While the forei^oing form prcstMits threat skill ami inge- 

 nuity in the architecture of its tube, the result falls short in 

 beauty of two species procured by the ' Challenger.' In the 

 first, TerebeJla {Lanice) seiicorm'sy from the mouth of the Rio 

 de la Plata, the aperture of the tube presents a ventral 

 tongue-shaped fiap, the dorsal ])illar supporting the base of a 

 tan — sjilit into a dozen primary filaments which, after a short 

 course, usually become bifurcate. Tlie lobe and tiie fan are 

 composed of tlie ordinary tough secretion, in which grains of 

 quarfzose-sand are neatly imbedded ; and as these are neces- 

 sarily almost linear in arrangement in the filaments, a sorne- 

 whal moniliform a[)])earance is produced. The attenuate 

 thread of the secretion forming the tip of each is strengthened 

 by spicules of sponges and bristles of annelids. The extreme 

 tip is occupied by a single long-winged bristle, which tapers 

 to a point; while another, lower down and parallel with it, 

 gives the region due strength and stiffness ; and in tlie 

 accomj)anying figure of the tube of a Norwegian Terehdlla, 

 kindly sent by Canon Norman, equal ingenuity is exhibited 

 (fig. 3, p. 10). It would be difiieult to find in the whole 

 invertebrate series an example of greater dexterity or of more 

 methodical adaptation. 



In the other, Terehella [Lanice) flahellam^ from Prince 

 Edward Island and the Australian region, the remarkable 

 fan-like expansion is mainly composed of the tough secretion, 

 stiflened by sponge-spicules and other linear structures, or by 

 grains of sand, all neatly and ingeniously arranged. 



The tubes formed by other members of the same family 

 vary mnch in character, many being composed of mud and 

 sanil, as Ampkitrite and Lanassa ; some chiefly of mud, as 

 Ni'colea, Le(ena, Pista, Trichoh ranch us, and Terehellides ; 

 while Thehpus and Grymaia have tubes containing a large 

 amount of secretion coated externally by shell-fragments, 

 zoophytes (calcareous and horny) , spines of echinoderms, and 

 other structures. One of the most interesting, however, is a 

 species [Eathelepus setuhalensis) procured by the ^Challenger' 

 off Setubal, in which the translucent cliitinous tube is in- 

 vested by a remarkable chevau.c-de-frise of Hexactinellid 

 sponge-spicules, which form an impenetrable glassy invest- 

 ment. A certain amount of selective power must have been 

 exercised by this species, since it lived in greyish mud with 

 numerous Globigerinte and other Foraminifers, some of wliicli 

 occurred in its alimentary canal. A species of Pista [P. mira- 

 hilis), again, has firm, round, tapering tubes armed all over 

 with long spines. The majority of tlie tubes seem to have 



