180 



LOWER /.V 1 -JCn TEBIIA TES. 



Another very worm-liku sjieeies, coiniiKni in Lahradoi-, is ('hirodotu leave. It is 



\vhitish-o;rMy, with wheel-like ])l:ite!<, like the last s|K'eics, slidwinu; as white spots. 



The two last nientioni'(l spi'eies lieloni;- to the family Svx m'tid.e, in which the 



sexes are nniteil in tlu' same iniliviilual, tiu' tentacles an- tinu'er-like, or lolmlated, 



nn<l the form eloni;ateil ami worm-like. 



In Si/iiaji(i( the inteuunient contains numerous jiei-forateil, tlai. calearcdus |ilates, 



t(i whicii arc attached ])rotrnding anchor- 

 like liodks. Mi/riotroch'us has a single 

 I'cilian \esiclc, lint Si/iiaptu has several. 

 Si/iKijifii (/inirdii is a common species upon 

 the Atlantii- sea-coast, living in sand at Ioav 

 tide level. Its exceedingly attenuated body 

 lireaks uji into several ]iieci's when tlic ani- 

 mal is itislurlie(l. Si/iii(j)tii siiiiilh is said 

 to li\i' in lirackisli water. Sijiidptiijn riri- 

 piira is one of those s|)ecie^ in which the 

 young de\'clii|i directly, and are ju'otected 

 in a marsupium. 



Oliijotroilnm rilrnn^ is a spt'cies living 

 at <leptlis of fri>ni fifty to two hundred 

 fathoms on the coast nf Norway, less \erjni- 

 forni tliau tSi/noiita, since its length is only 

 about four times its thickness, and sluggish 

 in its motions on account of the slight eon- 

 tracliiity and stiffness nf its body, which 

 is ti'ansparent and colcu'less. TJie tentacles 

 are twelve in nundici', and ai'e less devel- 

 oped than even in (lilrndttUi . The cal- 

 cart'ous plates, wlTn'li are whceldike, are 



\eij ttA\, and (lccj)lj sinik in the skin. 'J'he laleareous ring round the gullet shines 



snow-A\hltt thiough the body-wall, which also allows the intestines, generati^'c organs, 



etc., to be clearly seen. 



The next sub-order (I'neumojihor.ij has a respirattiry tree arising from the cloaca. 



Caudina is so called from the long, tail-like prolongation in which the body ends. 



The skin i.s rough externally, from the calcareous ])ieces imbedded in it. C arenata, 



the only species, has fifteen fo>n--pronged tentacles, and is a sonu'wliat common object 



in Massachusetts l]ay. 



J/o/jHidid tujy/ida, is a dee]i-\vater form that has been taken in over a hundred fathoms 



in the Gulf of Maine, and is known to range southward to Floi'ida. It is a tailed sjieeies 



with fifteen tentacles and an anterior extremity shaped like the neck of a bottle. 



Most of the Ajioda are natives of the cold seas of the Arctic regions, but some 



genera, as Synapta and Chirodota, are almost cosmojjolitan. 



^ipiapta inhanti with anchor.^ and plalc.« 



Okdei: III. — PEDATA. 



The Pedata, as their name im]ilies, are .-ilways furnished with a greater or less 

 number of ambulacral feet; a respiratory tree is always jiresent, and the sexes are 

 distinct. 



