488 PROK. A. DENDY AND MISS L. M, FfiEDERICK ON 
alate quadriradiates with short apical rays, forming a continuation ot the 
gastral skeleton, but with the paired rays arranged more regularly, parallel 
with the oscular margin. 
Spicules: — (1) Normal sagittal triradiates of the dermal cortex (PI. 26. 
fig. 8 c) ; with slender, gradually sharp-pointed rays ; the oral angle is very 
wide and the oral rays measure about 0'23 by 0'014 mm. ; the straight basal 
ray is longer than the orals and measures, say, 04 by 0'013 mm. 
(2) Subgastral sagittal triradiates (PI. 26. fig. 8 c') ; these are like the 
normal sagittal triradiates except that the rays are stouter and the orals more 
distinctly recurved ; the orals measure up to 0*3 by 0'026 mm., with the 
basal 0-5 by 0-03 mm. 
(3) Laterally extended (alate) triradiates of the gastral cortex (PI. 26. 
fig. 8 d) ; the oral rays are straight or very slightly recurved, gradually 
sharp-pointed, measuring up to 0'31 by 0'016 mm., and the oral angle is so 
wide that the rays are almost in the same straight line ; the basal ray is very 
short, straight and conical, measuring about 0"04 by O'Ol mm. 
(4) Alate quadriradiates of the peristome (PI. 26. fig. 8 e) ; these are 
similar to the alate triradiates, with the addition of a very short, straight, 
sharp-pointed apical ray. 
(5) "Tuning-fork" spicules (PI. 26. fig. 8/); with straight, slender, 
gradually sharp-pointed rays ; the basal ray is the longest and stoutest, 
measuring about 0'4 by 0'009 mm.; the two oral rays, which are slightly 
unequal in length, run straight forward parallel to one another ; the longer 
of the two measures about 0"21 by 0"006 mm. 
(6) Large stout oxea (PI. 26. fig. 8a) ; fusiform, slightly curved, some- 
times a little irregular in shape and diameter, tapering gradually to a sharp 
point at each end ; full-grown spicules measure up to 2'0 by 0'09 ram. 
(7) Slender oxea of the dermal brushes (PI. 26, fig. 8 b) ; straight or very 
slightly curved, gradually sharp-pointed, sometimes slightly hastate, 
measuring up to 1'6 by 0'007 mm., but often less. 
This species closely resembles Lelapia australis Garter, as described and 
figured by Dendy [1893 B], but differs in the absence of microxea ('• mortar 
spicules '') and in the presence of a definite layer of large, longitudinally 
placed oxea in the deeper part of the dermal cortex. In the latter respect it 
occupies an intermediate position between Lelapia australis and Lelapia 
nipponica, a remarkable Japanese species described by Hara [1894]. We 
have been unable to obtain access to the description of this species, but, 
thanks to the kindness of Dr. Hozavva, have been able to examine a number 
of transverse sections *. It is obvious that Lelapia nipponica is a much more 
primitive species than L. australis. The bundles of " tuning-fork " spicules 
are arranged almost strictly radially, with the unpaired rays centrifugally 
directed, and clearly represent the articular tubar skeleton, though the canal 
* Since tliis paper was read, Dr. llozawa [1923] has publislied an illustrated description 
of the .Japanese species and proposed for it the new genus Paraletapia. 
