LonidlilJANCU.S. 



661 



PHYSOCLYSTI LOPHOBEANCHIT' 



J'/n/sinh/sts iiilh lidlril IniiiiiliHil hliiiiiHf. 



This siiiLiic cliarMctcr is ciiuiiLih to divide IVniii the 

 rest nf the I'hysoclysts a series extremely reiiwirkMlilc 

 in iiiMiiN ri's]]ei-ts, wliich contains two families, ,ui<l of 

 which niir i'i|)ctishcs .-iiid tiie Sen-horses i it' wnrnier re- 

 gions nri' wcil-kiinwn txpes. 



The gills uf the Teleosts genei'.-dly cdusist, as is 

 well kiiiiwii, (if a great niindier uf liranehial lamiiuu — 

 (in tlie first liran^dual arch df a Cod .'1 dm. long, for 

 examjile, we can cdinir aliout 100 pairs — w liicli aw. 

 ai-range(l in a doulile mw (tii the outside (the eonvex 

 side) (if each lilvineliial ai'dl, like the teetil of a comb 

 liiii in pairs, each lamina altei'nating with (obliquely 

 opposite) the other lamina of the pair, thongii thev are 

 united Id ea(di other for a greater or less distance from 

 the iiase. Ivich of these lanunu' (tig. 1 fi(i) is furnished 

 (in each side (above and below) \\ith numerous, (raiis- 

 verseh-set lanudhe — in tlie Cod we can count as many 

 as 1,000, but in other Teleosts the\' are much fewer, in 

 the (hulgeon (dohlo fliirhitU'iA) for example, only oO or 

 60 — \\hich are honeycombed by the capillary network of 

 the respiratorx' vessels with a vie^v to the oxygenation of 

 the lilodd and its transmission from the braneliial ai'teries 

 to the iiranciiial \ citis. In the Lophobranchs the num- 

 ber of the bi'aucliial laminae is considerably reduced, in a 

 Pipefish, for example, being only 5 — 8 pairs on each 

 arch, the minimum number on the foremost and hindmost 

 of the four branchial arches, the maximum on the two 

 middle arches. Ibit to conipen.sate for this tlie com- 

 parati\el\- few liranehial lamella' are considerably en- 

 larged, being visible even to the naked eye, or at least 

 with the hel]) of a weak magnify ing-giass. They are 

 largest at the middle (jf each lamina, their size decreas- 

 ing regularly towards the base and the tip thereof; and 

 the lamina itself is curved, not unlike a peacock's feather. 

 "By means df this arrangement," says I'e'I'zh's, "the 

 branchial lamina' (tig. 1 67 ) ac(piire an appearance some- 

 thing like that of bunches of peacocks' feathers, set 

 alternateh' and touching each other with the convex 

 part of their curves. When we see the twd rows of 

 these bunches from without (tig. 168), the figure also 

 reminds us somewhat of the foliation of Suhinid." 



Fif?- Hit;. A pair of liriiiii-lii.il laiiiinM. altaclied to a sc-c-tidn of ii 



braiicliial arcli in tlie Cud. A, llir laiiicllic. Magnified and sclienia- 



ti/.cil. After 't'li. Wii.l.iAMS. 



Fig. 167. A pair of Ijrancliial laniin;u attaclied to a section of a 

 braneliial areli in 6'i/ii;/iwl/ii(s. Magnified. After .\. Retzius. 



Fig. 108. A braneliial arcli with its alternating lamina; and llieir 

 lanicdl.T in ^Si/ngiiatliiis. Magnified. After A. Retziis. 



" I/ordre des l.opliolirfinclies, Cuv., Regno Aniiii., ed. I, toin. II, p. 155. 



