LtMAX ARBORUM. 



Ill 



and tliick, with median inllatioii, ciisliioned with nclatinons matter, and possessing; a 

 wliite iKirn-sliaped glaiidnlar apiiendagu iif vaiialile ioii.ntli at its a]jex, Imt as tlie 

 seminal element is transferred free, this lla,nellate slime-,i;laiid has mithing in coninien 



Fig. Hn.— Penis-shualh 

 i^f LiiNax arl'oruiH laid 

 open, showing the iiUevnal 

 sLrncture (after Siinroth), 



Kl... lUS.— Alimentary 

 canal of Linia-v ar/.'07uni 

 (somewhat enlarged). 



Fi,;. lOn.-Se.xiial organs of /./;//,i.r aihifuij,, X a. ull',^ 

 h. heart ; k. kidney ; ot. o\'otestis ; oz'. oviduct ; /. prostate ; /).s. penis sheath 

 j/. spermatheca. 



-.III. retract'.) 



with the Hagelltiin of tlie HcliriiJiv, in whieli gron]! it is cmtcerneil in the foi'inaliim 

 of the siierniatophore; internally, tlie penis-sheatli shows two iirmninent longitudinal 

 muscles, and frec^iiently a lingiiifrjrm projeeticm, which may serve as a saicohclnni. ' 

 The penis retractor is a powerful muscle, attached to the Inng iloor in front of the 

 ceiihalic retractor; spkkmatheca pyriform, and opening into the atrium. 



The CEPHALIC EETKACTOR arises as usual fifim beneath the hind margin (jf the 

 shield, and run.s nearly half its length nitdi\ided ; it then trsually se|>arat(^s into three 

 branches; the right and left TKNTACULAi; and the pilAi:vX(;i:.\L nutscles; the 

 pharyngeal bifurcating soon after its seiJaration. The retractor to the |iliavynx 

 does not always separate froni the main stem simultaneously with the tentacular 

 branches, but may do ,so a little before or after the tentacular divarication. 



The MANDIBLE or jaw is about a millimetre 

 wide, not so convex as those of the allied species, „visiik ife-. 



of a yellowish brown cohnir, smooth and delicate 

 in texture, with rounded end.s, and with a very 

 wide, slightly projecting antl blunt median beak 

 or rostrum. 



The LINGUAL MEMPRANE in ordinary specimens is rtbtjut four mill, long and two 

 mill, wide, the transverse rows being arranged in the form of a welldelined priulei's 

 "brace"; the median row shows obsciirel\' tri<lentate teeth, the mcsocone exception- 

 ally broad and strong, and the ectocones ill-delined and N\itl]out perceptible cutting 

 points; the lateral teeth are also remarkable for the well-marked mesocone and the 

 indistinct side-cusps; the marginals are sinuate in shajie, ami at liist distinctly uni- 

 cus]iid, lait towards the outer rows an ectocone may be perceived on imtny of the 

 teeth, the extreme marginals being, however, simply aculeate. 



Fu;. III. — IMandilile or jaw o{ Liiiia.v 

 ■.rtoyiilll. .■:. W. 

 (ChristchurLh, Hants. S., C- Ashforil). 



Fm.. 112,— Representative denticles froiii a iraiisver.se row of the 1111^11. d teeth "I /,. arboriliii, /. 1211. 

 The animal collected at Christchurch by Rlr. C. Ashford, and the palate prepared by Mr. W. I\t.ss. 

 The obliteration of the side-cutting points on the medi.nn and lateral teeth is an 

 attribute of maturity, as the teeth of the young are. ;iccording to Miss l^smaik, 

 always ]irovided with lateral points. 



The formula ot a Christchurch specimen is " ■"• '"_L!itl±l.'i±iL;| x l(),"i=:il ;"i,4or). 



1 Monog. !., p. 3G.'i, f GtiT. 



