REPOET ON THE MONAXONIDA. 65 



of spiculo-fibre. The main fibres run vertically to the surface, branching freely as in 

 Esperella arenicola, nobis, and terminate in bunches of free spicules, the points of which 

 project a little way beyond the dermal membrane. 



Spicules. — (a) Megasclera ; of one kind only, viz., styli (PI. XV. fig. 2), with a slight 

 tendency to become tylostylote by the development of a long oval head ; broadest at 

 about the middle and tapering to a rather sharp point at the apex; size about 0'9 by 

 0'02 mm. (&) Mierosclera; large palmate anisochelse of very remarkable shape and 

 singular beauty (PI. XV. figs. 10, 10a) ; the whole spicule measuring up to 0"094 mm. 

 in length. They never seem to occur in rosettes. Numerous young ones are also 

 present. No other mierosclera are present, but the chelse occur in the greatest 

 profusion. 



This is one of the most satisfactory species in the collection, being excellently 

 characterised both by its external form and by its spiculation. In the absence of 

 a dermal skeleton reticulation it agrees with Esperella nuda and Esperella arenicola, 

 nobis, and difi"ers widely from Esperella murrayi, nobis, with which its definite 

 external form would seem to associate it. To the absence of a dense dermal reticula- 

 tion, such as exists in Esperella murrayi, is probably due the fact that the pores are 

 not collected into definite pore-areas, all parts of the dermal membrane, excepting just 

 where the spicular tufts project, being suitable for them. In connection with the great 

 development of the teeth of the smaller end of the anisochela it is perhaps worth calling 

 attention to this spicule in Esperia lanugo, Schmidt,' which is described as having this 

 end unusually developed, individual spicules showing a completely isochelate condition ; 

 it is not figured, but Schmidt would probably have descril^ed the outward turning 

 of the lateral teeth of the smaller end had it, as here, occurred in his species. 



Embedded in the soft tissues of the sponge, beginning at about a third of an inch 

 below the surface, are an immense number of Httle yellow embryos (PI. XVI. fig. 2a, e), 

 which will be found fully described in the Introduction. 



ZocaZ%.— Station 320, February 14, 1876 ; lat. 37° 17' S., long. 53° 52' W.; off" the 

 mouth of the Eio de la Plata ; depth, 600 fathoms ; bottom, green sand ; bottom 

 temperature, 3 7° "2. One fine specimen in excellent condition. 



Esperella parishii, Bowerbank, sp. 



1875. Raphiodesma parishii, Bowerbank, Proc. Zool. Soc. Lond., April 1875, p. 283. 

 1880. Amphilectus parishii, Vosmaer, Notes from the Leyden Museum, 70! ii. p. 119. 

 1884. Esperia parisU, Ridley, Zool. Coll. H.M.S. "Alert," p. 436. 



With this species we identify a thinly incrusting sponge from the Philippine Islands. 

 As it has been fully described (but unfortunately not figured) by Bowerbank (?oc. cit), it 



1 Jahresh. Comm. IFiss. Unters. deutsch. Meere, ii., iii. p. 118. 

 (zool. chall. EXP. — PAET Lix. — 1887.) Nnn 9 



