September 7, 1S83.] 



SCmNCE. 



307 



spending to each leg. The cords are united in front, 

 above llie oesopliagus. to form tlie cephalic ganglia, 

 and are also united behind over the anus. The 

 arrangement of the commissure and nerves of the ven- 

 tral cords is minutely described. The supra-oesoplia- 

 geal ganglia give origin to the immense antennary 

 nerves, and a few small epidermal nerves; laterally, 

 one-third of the way back, the optic nerves, and two 

 pairs of smaller nerves near the optic; still farther 

 hack, a large median nerve from the dorsal surface ; 



Fio. 2. Oonerftl iinntomy : the digcxtr 

 eicini'd ; the niivouB tiyHluin if ropr^ 

 antrnna; op, orul paptlla; br, brain; n 



pharynx; om, oeBupltagui*; com. connni_ 



li-ct; mo4. «o5. «o jr.sL'xmfnlalorganH; ay, 



9 o, geuilal opening; an, anus; u c, anal cumraisBurc 



cell. The surface of the cuticle is dotted over with 



minute spinous tubercles. Scattered over the bkin 



are organs of spi'clal 



sense, which I think 



resemble the olfactory 



organs of insects; but 



Ualfour regards (hem 



as tactile. Each Is a 



broad, conical, cutic- 



ular spine supported 



by large specialized 



sensory cells. 



The tracheae arise 

 from openings be- 

 tween the ridges of 

 the skin. Each aper- 

 ture leatls into a pit 

 formed by the invagi- 

 naled .••kin; and from 

 the bottom thereof 

 springs a bunch of 

 fine tiacheal tubes, 

 which display large 

 adherent nuclei on 

 their nails, and trans- 

 verse lines indicating 

 the presence of a spi- 

 ral fibre. The open- 

 ings form two rows 

 (subdorsal) on the 

 back, and two rows 

 on either side of the 



median ventral line; they are also fouiul on the feet, 

 around the bases of the feet, and on the lie.ad. 



The mu.Nf?(?.f of the jaws are alone striated: all 

 others are unstriated. The muscles of the body form 

 an external double layer of circular fibres, an inner 

 layer of longitudinal muscles forming live bands (one 



^la. 3. Anterior portion of 

 o>'«lem : ant, antenna) ne 

 eye ; 0, ventral aplK'ndai^c 

 tirwl commipBtire; J n. n 

 the jaw; «y, sympathetic 

 7>c, posterior lolie of brati 

 ner\'e« of the oral papilla 

 ganglion of oral nervee ; 

 eral nel-\'e(* of ventral chonlf ; Ji n 

 pedal nervert; /g 2, enlargemeni 

 correRponiiing tu pedal uerveM 

 CO, commi^ure. 



lal. 



tract Ik nuppofted to bo 



refenled in black : imt, 



»u/. salivary gland ; /i/i, 



/'■l,F:i,flT, 



e«8ory gland ; 



from the ventral siirface, the sympathetic nerves, 

 which follow the grooves of the pharynx, and unite 

 upon the dorsal wall of the oesophagus. The gan- 

 glion-cells are confined, for the most part, to the sur- 

 face in the supra-oesophageal ganglia, aiul to the 

 ventral Layer in the longitudinal cords. On the under 

 side of each lobe of the brain is a conical protuberance 

 of ganglion-cells, which Griibe regards as an organ of 

 hearing; but Halfour iiiieslions that interpretation. 



The »t(/i resembles that of other insects. The cuti- 

 cle is thin, and forms a separate conical cap over each 



'^%S 



Kii; 4. Hectlon of tracheal orilici: : o, cllcinal orilice; />, pit ; Ir, 

 tracheae; n, tracheal nuclei. 



lading median and ventral), and vertical septa of trans- 

 verse fibres (one septum on each .side of the alimt-ii- 

 tary canal): so th.at the body-cavity is divided into 

 three regions, — a median, containing the aliiiienlary 

 tract, slime-glands, etc. ; aud two lateral, containing 



