4S 0. R .IKXKIX. 



i>no sorious t>l>jeftit>n to this theory. The apiciil rays oi the ordinary quailrirailiatcs 

 wouhl have tit he heiil down and straiglitouod while the spieule tnrned round. The 

 shape of the apical rav in the cliiartines suggests that this does oeeur, but it is difficult 

 to realise how ;m actually formed .-ipicule can l>c altered in shape. 



Hair Spicules. — In many of the new species there oeeur long straight spicules 

 of extreme thinness, varying from about -7 fi to about - jx in diameter; they are 

 called hair spicules. Their length is alwa\s difficult to determine. When they 

 occur in the oscular fringe the outer ends are usually broken ; when they occur in the 

 body-wall thev are nsuallv so crowded together that it is impossible to distinguish the 

 ends of individual spicules. It is probable that they often attain to lengths of 500 /x 

 or 1.000 /ix. They often project from the body-wall with the ordinary thick oxea. The 

 hair spicules are usually omitted in the drawings of spicules, since their thickuess is 

 too small to draw to scale aud their length is uncertain. 



Flattened Spicules. — In two of the new species {Leueamira cirrata aud 

 Mt^/iijh'i/i'ii iv<\vy>(fC(^>.) tlie large projecting oxea are marked near their distal ends by 

 curious flattened areas situated ou the convex sides of the curved ends. Their 

 appearance might suggest that the spicule had come iu contact with some flat 

 obstruction which had diverted its growth and caused the mark. This, however, does 

 not seem to be possible, and no explanation of the origin of the marks has 

 been found. 



Ke PRODI" CTIOK. 



Larviv similar to those of Sj/coii cilitifuni were found in Tent hre nodes scoiti and 

 ^^e<^apt>^/on poUimris. 



Ova of the oixlinary type were found in Ifi/poiUcti/on and in Achramorplta 

 (jhu'ialis. 



Duplicate ova of a remarkable type were found in Achrainorj.i/ia niralis and 

 Megapo(ion rariplhis; no s^itisfactory explanation of their structure has been found. 

 Thev were in large unmbei-s iu three specimens of Achrami'rphu nivalis; the best 

 preparations were made from one of the specimens which had been fixed in osmic acid. 

 None of the .specimens of .]f((fap(Ujo)t riiripilus were as well fixed, nor could the 

 structure of the ova be made out .so .satisfactorily : it appeal's to ditier slightly from 

 that of ^[chniniorp/ia nirttlis. 



The following description applies ti> the ova of Ac/tniniorp/ia nirnlls: — 



Etich ovum (Fig. 110) appears to be made up of two unequal parts; the 

 larger part (a) is very similar to the ordinary large ovum i-ell and contains a large 

 transptireut nucleus (It) and small strongly staining nucleolus (c) : the smaller part 

 appears to be a multicellular structure, consisting of a large inner cell surrounded by a 

 sheath of small cells ((/) ; (but it is possible that it may be a single cell, the central 

 p*.>rtion ((/) being the nucleus). The inner cell ((/) contains two structures ; one (A) 

 strongly staining like the nucleolus of the larger part, the other a hvaliue sphere (/) 



