76 THE VOYAGE OF H.M.S. CHALLENGER. 



(1) very minute palmate anisoclielse, length about 0'0126 mm ; (2) small, slender 

 sigmata, often contort; length about 0'025 mm. 



This species forms a most interesting and important link between the two oenera 

 Esperella and Cladorhiza, especially as regards external form. It is also particularly 

 interesting in that it exhibits a distinctly bilateral symmetry ; in this respect it is 

 approached by Cladorhiza pennatula, Schmidt;^ the latter has, however, a much coarser 

 and less delicate form. 



The species may be readily recognised by the very minute microsclera, the 

 extraordinary external form, and the two kinds of megasclera, though the latter are 

 both, doubtless, merely modifications of one and the same type. 



Localities.— Btation 281, October 6, 1875 ; lat. 22° 21' S., long. 150° 17' W. ; South 

 Pacific ; depth, 2385 fathoms ; bottom, red clay ; bottom temperature, 34°'9. One 

 specimen, which still retains the soft parts. 



Station 291, October 27, 1875; lat. 39° 13' S., long. 118° 49' W. ; South Pacific; 

 depth, 2250 fathoms ; bottom temperature, 34°'6 ; bottom, red clay. One specimen, 

 with the soft parts washed off", but still retaining a few microsclera and exhibiting very 

 beautifully the biserial arrangement of the lateral processes.^ 



Esperella sp. 



We have to record the occurrence of a single specimen of an Esperella (species 

 unknown) from Bass Strait, which is growing over the fibre of a Dysidean sponge ; 

 both the tylostylote megasclera and the anisochelse are very much reduced, and we 

 have seen no other kind of spicules. Under these circumstances it has not seemed to us 

 desirable to found a new species for the reception of this sponge. The tylostyli are 

 smooth, straight, slender, sharp-pointed, with slight oval heads, and commonly with much 

 enlarged central canals ; size about 0-28 by 0-0042 mm. The palmate anisochelse are of 

 very delicate appearance and about 0"022 mm. long. 



ZocoZ%.— Station 162, April 2, 1874; lat. 39° 10' 30" S., long. 146° 37' E. ; Bass 

 Strait ; depth, 38 fathoms ; bottom, sand and shells. One specimen. 



Genus Esperiopsis, Carter (Pis. XVIIL, XIX., XXVL, XXX., XLVL). 



1882. Esperiopsis, Carter, Ann. and Mag. Nat. Hist., ser. 5, voL ix. p. 296. 

 Form various, amorphous or symmetrical. Megasclera all monactinal, styli or 

 tylostyli, smooth ; microsclera isochelse, to which sigmata may be added. 



1 Jdhresb. Comm. wiss. Untersvch. deutsch. Meere, Jahrg. ii., iii. p. 119, pi. i. figs. 14, 15. 



^ Lodged right witliin the spicular axis of one of the specimens were found a number of developing embryos, con- 

 cerning which further details will be found in the Introduction. For this interesting discovery we are indebted to the 

 careful observation of onr artist, Mr. P. Higbley. 



