STAUEOCALYPTÜS GLABEE. 213 



Excurrent canalar apertures ou the gastral side are ou the 

 whole much smaller and situated more closely together than the 

 iucurreut. The canals they lead into are deep and pit-like, unlike 

 those of the iucurreut system. 



The soft paris (see PL XV., fig. 11) were studied hy me 

 but without results of any special interest. The limiting trabe- 

 culœ of both the dermal and the gastral surfaces are to a great 

 extent membranously developed. The free proximal ra3'S of the 

 gastralia heave up the gastral membrane in a tent-like manner. 

 External trabecule are most numerously present Avhere the choano- 

 some most closely approaches the ectosome. A large part of the 

 wide subdermal spaces is quite free of them. Chambers, of the 

 usual shape and appearance; 100-165 // in diameter. Arclueocytes 

 and thesocytes much as I shall later describe from Rhabdocalyplaa 

 capillatus (PL XXIII.) . 



Spiculation. 



PL XV., fig. 11, will serve to give a general idea of the 

 spiculation. 



The parcncJiymal princlpalia are elongate spindle-shai)ed oxy- 

 diactions with rough-surfaced ends and aie more or less bent in 

 a bow-like manner. They may attain a length of 13 mm. and a 

 thickness of 190 n in the middle. The smaller ^^'ii'enchymalia 

 and the comitalia are of the usual characters. 



The diactinic proslalia, present on the younger specimens, 

 may be 25 mm. long or longer. In thickness they may measure 



