Sijnop.si'^ of the A ((■^fralian Cahiarea Hefevocud't. 113 



skeleton of tlie chamber l;t3^er is nuule up of lai-ii'e Mib- 

 dermal and subgastral .sagittal tri radiates, whose basal rays 

 penetrate the chamber layer in opposite directions. These 

 spicnles vary greatly in size, the basal rays often extend 

 completely through the chamber layer aiicl are very thick; 

 the oral rays are shorter, more or less curved and widely 

 extended. Frequently many of those which have centrifugal 

 basal rays are not strictly subg.istral but ha\-e the oral i-ays 

 situate at various levels in the chamber la^^er. The i-ays 

 are conical and gradually sharp-pointed. The dermal cortex 

 is about 0-i mm. thick and its skeleton is rande up almost 

 entirely of triradiate s{)icules ot various shapes and sizes. 

 Towards the inside we find large, I'eguiar or subregular 

 triradiates, arranged parallel to the dermal surface, with 

 conical, gradually sharp-pointed rays which measure up to 

 about 10 by 0' 17 muj.; man\^, however, being much smaller. 

 On the outside is a much thinner layer of veiy different, 

 small triradiates. These spicules are irregular in sha])e and 

 irregularly arranged ; their rays are conical and gr;iduall\' 

 sharp-pointed, but crooked ; one of them commonly projects 

 inwai'ds at right angles to the <lermal surface ; the rays 

 measure about ()-083 bv 000'i2 mm. We also find in tlit' 

 outermost part of the dermal cortex a few very minute, 

 straight, slender oxea, whose exact size and shape are ver\^ 

 difficult to determine. The osculai- skeleton consists of a 

 fringe (not always visible to the naked eye but sometimes 

 strongly developed) of very long and veiy slender oxea. 



I i)ave much pleasure in dedicating this very remarkable 

 and abundant species to Mr. J. Biucebridge Wilson, who lias 

 collected all the specimens at present known. 



Locality.— OntHide Port Phillip Heads (coll. J. B. Wilson). 



08. IJ('ieroj)egin(i nodus <jordii, Polejaeff. 



Heteroperpmi /^(^tl((NW/u/'(7//, Polejaefi! Re[)ort on the Cal- 

 carea of the Challenger Expedition, p. 4-."3. 



The only specimen which I have seen of this species, 

 unless indeed H. latitubulatd, be considered specifically 

 identical, is a portion of Pol^jaeff's type specimen in the 

 British Museum. I have nothing to add to Polejaeff 's 

 excellent description. 



Locality. — Torres Straits (Polejaeff. Polejaefi" also records 

 the species from the Bermudas). 



I 



