454 " THETIS " SCIENTIFIC RESULTS. 



Of species previously described the following are the most 

 worthy of note : — 



Siphonockalina aimufata, Ridley and Dendy. 



Arenochalina mirxibilis, Lendenfeld. 



Geraochalina levis, Lendenfeld (with its so-called algal 



pseudomorph). 

 Esperella murrayi, Ridley and Dendy. 

 Esperiopsis cylindrica, Ridley and Dendy. 

 Pseudohalichondria fibrosa, Whitelegge. 

 Amphilectus ceratosus, Ridley and Dendy. 

 Desmacidon firuticosa, Bowerbank. 

 Rhizochalina pntridosa, Lamarck. 



MONAXONTDA, Rzd/ey and Dendy. 



Order HALICHONDRINA, Vosmaer, 



Family HAPLOSCLERID^, Toi^sent. 



Subfamily CHALININ^, Schmidt 



C H A L I N A, Grant. 



CHALINA MACROPORA, Lendenfeld. 



Euchalina macropora, Lendenfeld, Zool. Jahrb., ii., 1887, p. 818. 



Station 53. 



A single example is here, somewhat doubtfully, referred to this 

 species. A comparison with a fragment from the British Museum 

 has been made, and it agrees with the "Thetis" specimen in 

 external and general characters, but the spicules differ slightly 

 in dimensions. 



Sponge with numerous slender, erect, cylindrical branches; the 

 latter are dichotomous at their origin, but when mature the lobes 

 are unequal, their diameter varies from 5 to 10 mm., and they 

 attain to a height of 220 mm. The sui'face is even, harsh to the 

 touch, and exhibits a rather distinct reticulation, with abundant 

 small pores and numerous shallow oscula ; the latter are from 

 1 to 3 mm. in diameter, from 2 to 5 mm apart. 



The skeleton consists of an open network of fibre with the 

 mesh mostly square, rarelj' oblong. The primary fibres are about 

 005mm. in diameter and 0-2 to 0-3 mm. apart. The core of 

 oxeote spicules is more or less plumosely arranged, with their 

 basal ends approximated and their apices divergent ; they vary 



