290 Transactions. — Zoology. 



(2.) Spined oxy - strongyle of dermal cortex: A beautiful 

 spicule, not always easily found, but always present, and 

 sometimes abundant. The spined portion is usually about 

 one-quarter of the whole spicule, and terminates in the 

 rounded, distal end. From this end the spicule tapers evenly 

 to a sharp point. Measurement, 0-28mm. x 0-01mm. 



(3.) Triradiates of dermal cortex : These are generally 

 irregular or slightly sagittal, the oral rays in the latter case 

 being slightly curved towards each other : the rays may be 

 035mm. x 0035mm. They sometimes taper evenly to a 

 point, but generally they taper more rapidly at the ends. 



(4.) Oxea of cortex and parenchyma from 007mm. to 

 O'lmm. x from - 005mm. to 0-01mm. The spicule is thicker 

 at one end than at the other, and near this end it makes a 

 well-marked bend. Towards the sharper end there is usually 

 a curve in the opposite direction, the spicule having thus a 

 slightly sigmoid outline. 



(5.) Oxea of peristome : Long and thin spicules, thickest 

 in the proximal portion. l'5mm. x 0015mm. 



(6.) Triradiates of peristome : These are very graceful 

 sagittal spicules. The basal ray is very slight and tapering, 

 and may measure 045mm. x 0-008mm. The oral rays are 

 flattened in the plane of the basal ray, from which ray they 

 usually diverge at an angle of about 50° ; they curve slightly 

 inwards from the plane of the basal ray, and they may also 

 curve very slightly upwards or downwards. The outline of 

 the oral rays may be tapering or curving, the rays being 

 often widest and flattest at about two-thirds of the dis- 

 tance from the point of origin. Measurement of oral rays, 

 0'15mm. x 0015mm. These spicules are arranged with great 

 regularity at the base of the peristome on the inner side, the 

 basal ray directed downwards, and the oral rays spread across 

 the lower parts of the oxea of the peristome. It may be noted 

 that the gastral epithelial cells are well marked till just above 

 these spicules, where a well-marked sphincter terminates the 

 endodermal tissue. 



(7.) Quadriradiates of gastral surface : Near the oscule the 

 gastral surface shows large sagittal quadriradiates, which vary 

 greatly. Generally the rays, which have a curving or wavy 

 outline, have rather blunt points. Basal ray, 0-26mm. x 

 0025mm. ; oral rays, from 02mm. to 025mm. x 002mm. ; 

 apical ray, from 01mm. to 0-15mm. x 002mm. to 0025mm. 

 These spicules are not numerous. 



The larger exhalent canals and the lower part of the gastral 

 cavity are freely armed with small dagger-shaped 4-radiates, 

 much like those of Leucandra gladiator, Dendy. The rays lie 

 almost in the same plane. The basal ray is short and stout, 

 002mm. x 0008mm. The oral rays, which are of about the 



