REPORT- ON THE MONAXONIDA. 147 



1880 improves upon it with the following: — "Rods smooth or spined, ' echinating.' 

 Anchors minute, equiended ;" this also is very wide and really does not give so good an 

 idea of the genus as Schmidt's original diagnosis. It has seemed to us advisable to 

 restrict the genus by the diagnosis given above. 



In 1880 {loc. cit.) Vosmaer placed Clathria amongst the Desmacidonidse, saying: — 

 " I have found that the genus Clathria of Schmidt possesses distinct, often very 

 numerous anchors and bows ; so it is to be placed under the Desmacidinse ;" this 

 certainly appears a sensible arrangement, but in 1885 he adopts a different plan and 

 places it apart from the Desmacidines, amongst the Ectyonidse.^ We have endeavoured 

 to show elsewhere that the old Ectyonidse and Desmacidonidae must fall together in 

 one group, being connected through the genus Myxilla (cf. p. 129), in which both 

 species with and species without echinating spicules are found. The two genera Clathria 

 and Myxilla seem to be nearly related, and our Myxilla frondosa forms an interesting 

 connecting link. 



The original type of the genus is Clathria corall aides, Schmidt {loc. cit, p. 58), an 

 Adriatic species ; but this species is, unfortunately, not a very good example of the 

 genus as now understood; the next one mentioned by Schmidt {loc. cit.), viz., Clathria 

 comi^ressa, appears to be much more typical. Tenacia clathrata, Schmidt,^ is simply a 

 Clathria with very great actual and relative development of the horny fibre. 



Clathria appears to be essentially a shallow- water genus ; and this fact is no doubt 

 correlated with its horny fibre and fondness for warm seas ; the slight exception presented 

 by Clathria inanchorata {vide infra), from a depth of 120 fathoms, is associated with an 

 aberrant spiculation. 



The distribution of the genus is wide in tropical waters, but it seems to be best 

 represented in the Indo- Australian area ; as in the case of other horny sponges the genus 

 attains its maximum of development in warmer climates. 



Clathria aculeata, Ridley. 



1884. Clathria aculeata, Ridley, Zool. Coll. H.M.S. "Alert," Brit. Mus., p. 443, pi. xl. fig. i; 



pi. xlii. fig. K. 



This species was obtained by the " Alert " in Torres Strait, in which locality the 

 Challenger also found it. It has already been sufficiently described and figured in the 

 " Alert " report {loc. cit.). 



Locality.— Station 186, September 8, 1874; lat. 10° 30' S., long. 142° 18' E. ; 

 Torres Strait ; depth, 8 fathoms ; bottom. Coral mud. One specimen. 



Habitat. — Torres Strait, shallow water (" Alert " and Challenger). 



1 Bronn's Klass. u. Ordii. des Thierreiohs, Porifera, p. 356. 



2 Spong. Atlant. Gebiet., p. 56. 



