42 SVKN LOVEN, K('lll.\(il,(i(il(' A. 



]ii'osont"s, ;is alicady (»hscrNcd Ity (i iKsr.KiiciiT,' an area \\('ll 

 (leliiKHl by its want of i^-loss, //'//. I lo, H;.\ 1 !:'>, 110, 117, l:>i), 

 l:JI, J24, X and a<;Toein_<;' in form and cxtiMision witii tlie o])po- 

 site area ot" tlic slidc. Tlic intcrxal hciwccn lioth ai-cas is lilicd 

 \\'\\\\ a Hhi'ons iissuc, /'/. .\. ////. /;.-'.> +, by nicans of wliicb thc 

 tooth is btdd tii;'litly lixcd. The (bill area. of fhc tootli lo wbich 

 Ihis tissue is attached, is ron^lKMicd and a(la])ted tliereunto I>y 

 nieaus of a sliai-])ly (bdincd snpci^licial layci-, ////. 12(i, 127, 1:JS, 

 ofdrnscly ])a(d<('(b paralUd, slii>'htly tlcxnous oalcilicd tilaiucnts 

 conncclt-d I rans\-ei'st'ly or bifnrcatod luM-c and tbcrc, so as t(» 

 fonn b-ngtbcncd and narrow incslics. 'rbey are su])])orted, as 

 scMMi in a lon_<;it udinal section, ////. I.'J7, by slioi'f transluceut 

 ]»illars, w bicb, in a transvorse soction, ////. 128. from i ho striiigs 

 l)piii^' enl oir. appcai" as bea(b'd knobs, projiM-ting- from tlie 

 iiuii'ji;iiis of iht' hnncls. 



Sucb is IIh' arraiigomcni of thosp. parts in (^i(hiris, //'//. 

 110 — ii.V, Asthenosonia, ////. 1/(1—118, Ecliinofiirix, Astropyga, 

 Diadonui, //'//. llU, (VMitrostophanus, and others tlie teeth of 

 whicli are sim])l\' concavc on their inner side. It obtains also 

 amoni;' tlio g-enera ba\in_i;' fbc tcctb ])rovid(Mi with a cariiui on 

 thc insi(k', in Ihe Kchinns osculontns L., ////. 12(f — l:J!f, and K. 

 miliaris liKSKK, tlie Spluvrechinus <;-rannbiris Lamck., the Tri- 

 ])nenstes esculentus JjKskk, the Bolt>tia i)ileolus Lamck., the Pseu- 

 doboletia indiaiia Micii., tlie Echinttcidaris nii^Ta Mok., the Kclii- 

 nometra laionntcr ii., Ihc Heteroeeutrns mamillatns L. Bnt 

 in se\tMal othcr forms, as the Kchinns ang-ulosus Lkskk, tlie 

 Strongyloceiitriis lividus TvAMck., //'//. 1,')0, the Str. fraiiciscanns 

 Al. A(J., and Str. driibaoheiisis O, F. M., tlie IVmnopleiirus 

 Hardwicki (^l!A^, the Salmaeis snlcata A»i., the canal is \er\- 

 mmdi reduced or has entirely disaj)peared. tlie pyramid pre- 

 sentiiig a rounded mesial surfae»' conforiiiing to the back of 

 the tooth. 



In both great di\ isions of the Regnlaria the dental appa- 

 ratus, JV. 17, luvs t\)r its external motor muscles, present everv- 

 were, the iiiter-p3'raiiiidal luuseles, the iive pairs of m. pro- 

 traetores Stkwart, vi. pro , (ni. eouniiiiiutores Valkntin), the 

 iive of ni. retraetores Stkw., »i. re, (m. dilatatores Val.) and 

 the ti\t> of ni. radiales Stkw. (ligamenta obli(|na externa Val.). 



' 1. c. p. 8(;. 



