On Aasfntlutn lutts hitlicrto reftrreil (u Uoiiilaius. 61 



tractile, so that the movonicnts of the region will affect these 

 ehanncl.s, espceially as the stroma is lax. Towards the coin- 

 ineiieetntMit of the lateral iierve-i-onls, the vascular trunks 

 are fountl at their iun<.'r borders, and in some sections more 

 than one trunk oeeurs on each side at the commencement. 

 The hypoderm and basement-tissue of the snout aie largely 

 developed, the basement-tissue especially being massive in 

 the oesophageal region, where it is more bulky than the 

 cireidar muscular coat within it. So far as can be observed 

 in sections of the anterior region of the proboscis, the nerves 

 (elastic layer, M'l.) are at least 11 in number*. The 

 cerebral organs are in front of the ganglia, and the gut- 

 pouches do not come forward to the brain, the succeeding 

 region, as in A. luctijlorens, being occupied by the thick- 

 walled oesophageal section of the alimentary apparatus. 



KXrLAX.VTIOX OF TIIK I'LATES. 

 Tlatk II. 



Fiff. ]. T-aternl v'n'w of tho very younpr Pfij/ciK hlennoiilm. Enlarged. 



Fl(j. '2. \'intral view of tlie forp<roinf. Similarly enlarged. Tlie ex- 

 pansions of the ventral tins are indicated towards the tip. 

 Tlie straiffht line indicates the natural size of the example. 



I'i(/. 3. IJestoralion of tlie parts at the fork of the Cerehrfitulus from 

 Naples, by Mr. R. V. Puimett, M.A. (Cantab.), xlo dianis. 



circ.m., circular muscular fibres; fl.h.r., dorsa! loiiiiituilinal 

 vessel ; i.l.in., inner longitudinal muscular fibres ; i.n.c, inner 

 nerve-cords ; l.b.r., lateral blood-vessel ; n.c, outer nerve-cords 

 (ordinary); o.l.m., cuter longitudinal muscular layer; o.u.c, 

 outer nerve-cord of bifid region ; rh.c, proboacis-sheath. 



TLiTE III. 



Fii/. 1. Bidd Cerchrotiiliis oiu/u!atus, sent by Dr. C. II. Williamson from 

 Aberdeen Bay. The left side shows the ventral aspect witli the 

 mouth in front, whilat the bifid tail is viewed from the dorsum. 

 About natural size. 



i'/y. 2. Bifid Cerehm till 1(8 "jiiarr/inafus" from Naples. The figiue (which 

 is inverted^ is copied from a water-colour by Mr. U. C. I'unnett. 



VIII. — On the Generic Arrangement of the Australuin Rits 

 hitherto rejerred to Conilurus, icith Remarks on the Struc- 

 ture and Ewlution of their Molar Cusps. By Oldfield 

 Thomas. 



Ix coimection with the working out of some Australian 

 Muridte recently received by tiie British Museum through 

 the generosity of Sir William Ingiara and the lion. John 



• These were best seen in sections of the proboscis by Dr. Tosh. 

 Ann. <£' Mag. N, Hist. Scr. 7. Vol. xvii. 6 



