FROM THE society's GARDENS. 649 



The Receptaculimi seminis. 



Philopterus cehlebrachys (text-fig. 4). — Piaget (3, p. 30), in 

 describing this species, says : — " A la face ventrale deux bandes 

 longitudinal es sur les cotes de la valvule qui est peu visible, et 

 deux taches arquees dos a dos, avec un petit cercle de chitine en 

 ■avant." As Mjoberg points out (6, p. 256), this " petit cercle de 

 chitine," figured by Piaget in several species, is not a superficial 

 character of the exoskeleton, but a part of the receptaculum 

 seminis strongly chitinised and showing through the integument. 

 The receptaculum consists of a small more or less circular sac of 

 soft delicate tissue carried by a dark-brown thickly-cliitinised 

 calyx at the end of a fine duct leading into the genital chamber. 



Text-figure 4. 



Fhilopterus cehlebrachys. Keceptaculum seminis, X IOC 

 a. sac. C. calyx. D. duct. 



Mjoberg calls this a " kreisrunde Chitinscheibe," and figures it in 

 Nirinus lineolatios just as if it, indeed, were a flat circular disc on 

 one side of the base of the sac. In P. cehlebrachys the calyx is a 

 saucer-shaped piece of chitin with a rim. The duct enters through 

 the centre of its membranous bottom and debouches at the tip of 

 a large chitinous cone, which overtops the side of the calyx and 

 at its base is continuous witli the calyx, so that in optical section 

 it looks as if the bottom has been pushed clean through the 

 centre. 



In an Owl Philopterus of the cursor type, from Asio otus, the 

 calyx diflfers from that in the preceding in several respects. The 

 outer surface is closely striated in a more or less longitudinal 

 direction, the constriction below the rim is deeper, and the 

 " cone " is parallel-sided at its upper end and has a truncate 

 broad top. 



Proc. Zool. Soc— 1916, No. XLV. 45 



