REPORT ON THE MONAXONIDA. 131 



ends of the tornote spicules may sometimes become flattened and slightly spined. The 

 Challenger variety, again, has a firmer and more regular skeleton. 



Neither Lieberkiihn nor Schmidt {loc. cit.) mention the chelate spicules, but Vosmaer' 

 records their presence, and we have ourselves found them in one of Schmidt's specimens 

 now in the British Museum. 



Lieberkiihn and Schmidt obtained their specimens from the Mediterranean, and it 

 is of considerable interest to find an only very slightly modified variety occurring at 

 Japan. 



Locality. — Kobe, Japan ; depth, 8 to 50 fathoms. Three specimens and some 

 fragments. 



Habitat. — Mediterranean (Lieberkiihn, Schmidt); Japan (Challenger). 



Myxilla digitata, Eidley and Dendy (PL XXVL fig. 2 ; PL XXVIL figs. 5, 5a, bh). 



1886. Myxilla digitata, Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, vol. xviii. p. 471. 



Sponge (PL XXVL fig. 2) represented in the collection by a single specimen, 

 about 31 mm. long and 12 mm. broad, cleft at the upper end into five finger-like 

 lobes, whence the specific name. Colour in spirit greyish-yellow. Texture soft and 

 spongy. Surface smooth but uneven and corrugated. Dermal membrane distinct, 

 thin, transparent. Oscula small, scattered, having their margins flush with the surface. 

 Pores scattered. 



Skeleton. — (a) Dermal ; consisting of tylote spicules loosely scattered in the dermal 

 membrane. (6) Main ; a close but irregular and somewhat Halichondrioid reticulation of 

 spined stylote spicules. Fibres very indefinite. 



Siyicules. — {a) Megasclera; (1) entirely spined styli (PL XXVIL fig. 5), usually 

 slightly curved and tapering gradually to not very sharp points, with no tendency to 

 the formation of heads and with the base no more spined than the remainder of the 

 spicule; spination well marked ; size about 0"4 by 0"014 mm.; (2) tylota (PL XXVIL 

 fig. 5a), straight and with well-developed heads; size about 0'24 by 0'006 mm. 

 (6) Microsclera ; of one kind only, viz., tridentate isochelse (PL XXVIL fig. 5&), with 

 strongly curved shaft ; length about 0'044 mm. 



This species is readily distinguished from Myxilla {Hymeniacidon) paupertas, Bk., 

 with which it agrees in several respects, by the absence of the echinating stylote 

 spicules. 



ioca%.— Station 142, December 18, 1873 ; lat. 35° 4' S., long. 18° 37' E.; south 

 of the Cape of Good Hope; depth, 150 fathoms; bottom, green sand; bottom 

 temperature, 47°'0. One specimen. 



> Notes Leyden Mus., vol. ii. p. 12J, 1880. 



