BY R. VOX LENDENFELD, PH.D. 1123 



19. GENUS. LEUCOKT1S. Von Lendenfeld. 



Leuconidae with acerate and triradiate spicules. This genus 

 is nearly identical with Haeckel's Genus Leucortis. 



38. SPECIES. LEUCGPTIS LORICATA. Von Lendenfeld. 

 LEUCONIA LORICATA. N. Pole>eff(l.) 



This species represented by a single specimen, 30 mm. long and 

 8 mm. broad, possesses a strongly developed cortex - 5 mm. 

 thick, the width of the whole wall being 2 mm. consisting of 

 several parallel layers of sagittal triradiate spicules ; a quite 

 irregular disposition of the Parenchymal spicules, only those 

 which are near the inner surface lying more or less parallel to it ; 

 minute spined acerate spicules scattered everywhere in the body, 

 but chiefly coating the inner surface. The structure of the canal 

 system presents no deviations from the general type. 



Spined acerate spicules 0-025 mm. x 0-002 mm. Numerous on 

 the inner surface, they are very rare in the Parenchyma and in 

 the coxtex. Triradiate spicules of the Parenchyma, either quite 

 regular or rather sagittal and irregular; rays straight, tapering 

 from the base to sharp points ; surface more or less smooth ; the 

 proportion between the length and thickness 8-1, the length 

 0-6—1 mm. 



Cortical triradiate spicules, sagittal, all rays lying in the same 

 plane, tapering from the base to a more or less rounded end, 

 usually of the same thickness, the proportion between this latter 

 and the length varying from 10-1 to 16-1 ; basal ray straight, 

 sometimes rather thinner than lateral rays forming with each of 

 these latter an angle of 115°, lateral rays either straight or 

 slightly curved forwards, 0*325 — 0-5 mm. long, usually somewhat 

 shorter than basal ray, often of the same length, sometimes even 

 rather longer. In the wall of the collar these triradiate spicules 

 become smaller, their rays being rarely longer than 0-15 mm., 

 with a diameter of 0-0125 mm., and show a regular disposition. 



( 1 . ) V. Polejaeff'. Report on the Calcarea. The Zoology of the Voyage 

 of H.M.S. Challenger. Part XXIV., p. 63, pi. II., fig. 2; pi. VII., 

 figs. 6a. -6b. 

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