106 OKHAMANDAL MARINE ZOOLOGY REPORT PART II 



13 mm. in diameter. The surface is not strongly hispid, but is covered with an 

 encrustation of sand-grains between the projecting ends of megascleres. Three 

 small mammiform projections, terminally fringed with projecting spicules, pre- 

 sumably indicate vents ; another smaller one, without a terminal fringe of 

 spicules, may bear inhalant pores. Colour internally pale greyish-yellow. 



There is a well-developed, dense cortex, about 0-26 mm. thick, full of granular 

 cells and perhaps to some extent fibrous. 



The skeleton radiates from a very dense central " nucleus " and consists of 

 well-defined bundles of oxea and triaenes, the bundles being separated from one 

 another by fairly wide intervals free from megascleres. 



The cladomes of the orthotrieenes and anatrisenes for the most part he in the 

 cortex, but some of them project, along with the ends of some of the oxea, 

 into the encrusting layer of sand and foreign spicules. I have seen no protriaenes, 

 neither in sections nor in boiled-out preparations, but it is quite possible that their 

 ends lie outside the cortex and have all been broken off. 



Spicules. (1) Oxea ; very long, straight, slender, fusiform, tapering very 

 gradually to a fine point at each end, but one end may taper less gradually 

 than the other ; size up to about 2-9 by 0-05 mm. 



(2) Orthotriaenes (Fig. 3 a) ; shaft tapering very gradually to a long-drawn-out, 

 hair-like extremity ; cladi simple but often irregularly bent, normally conical, 

 sharp-pointed, gently recurved. Dimensions of a typical example : shaft 1-6 by 

 0-03 mm. (thickness just below cladome), cladi about 0-17 by 0-025 mm. In 

 another example, of different proportions, the shaft measured about 1-0 by 

 0-037 mm. and the cladi 0-26 by 0-033 mm. Sometimes the hair-like portion of the 

 shaft is abbreviated and abruptly truncated. 



(3) Anatriaenes (Fig. 3 b) ; shaft very long and slender, hair-like, measured 

 up to about 2-75 by 0-007 mm. (thickness just below cladome) ; cladi slender, 

 sharp-pointed, about equal, recurved not very abruptly, measuring about 0-06 

 by 0-006 mm. 



(4) Sigmata (Fig. 3 c) ; very slender, spirally curved (contort), measuring about 

 0-012 mm. in a straight line between extreme points ; of the typical tetillid form ; 

 extremely numerous in the choanosome. 



(5) Trichodragmata (Fig. 3 d) ; bundles of long, slender, hair-like raphides ; the 

 entire bundle may measure up to about 0-13 by 0-028 mm. Abundantly scattered 

 through the choanosome. Usually they contain fewer raphides and are therefore 

 more slender than the specimen measured. 



The most characteristic feature of this species is the presence of the tricho- 

 dragmata, which, so far as I am aware, are known to occur in only one other 

 species of Tetillidge, viz. Cinachyra eurystoma Keller [1891]. 



Register Number and Locality. XXIII. 8, off Dwarka, 15-17 fins., 12.12.05. 



