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



sponge was living. Length of the stalks about 50 mm., with a diameter at the broad 

 end of about 2'5 mm. 



Spicules. — [a) Megasclera ; slender styli (PI. XXI. figs. 7, 7a), which may attain 

 in the stalks a length of over 4*5 mm., with a diameter of about 0-07 mm. (h) Micro- 

 sclera; isochelae (PI. XXI. fig. 12), with long shaft and six or seven teeth at each end ; 

 length about 0-094 mm. Shaft slightly expanded towards each end. The sigmata are 

 virtually absent though two or three very slender ones were seen, measuring about 

 0'056 mm. in length, which may or may not be proper to the sponge. Oscar Schmidt 

 also mentions no sigmata in his specimens (loc. cit.) ; his remarks about the shape 

 and size of the microsclera run as follows : — " Es sind zwei Sorten von Doppelankern 

 vorhanden. Die eine, kleinere von 0-02857 bis 0-0311 Mmtr. zeichnet sich durch unver- 

 haltnissmassig lange Zahne aus, deren Enden sich fast beriihren. Noch eigenthiimlicher 

 ist die andere, besonders grosse, von 0-07142 bis 0-12 Mmtr. Sie besitzt namlich keinen 

 Mittelzahn, sondern statt dessen ein Paar Ziihne, daneben jederseits noch zwei, also im 

 Ganzen sechs Zahne. Im Schaft, der in der Nahe der Zahne, wie so oft, mit seitlichen 

 Ausbreitungen versehen ist, sieht man schon bei massiger Vergrosseruug den Axeneanal." 



Possibly the small chelae here described are young forms of the others, we have not 

 found any in our specimens. 



Localihj. — Station 248, July 5, 1875 ; lat. 37° 41' N., long. 177° 4' W.; North 

 Pacific ; depth, 2900 fathoms ; bottom, red clay ; bottom temperature, 35°-l. 

 Fragments. 



Chondrocladia clavata, Ridley and Dendy (PL XX. figs. 1, la; PI. XXI. fig. 11). 



1886. Clwndrocladia clavafa, Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, vol. xviii. 



p. 345. 



Sponge (PI. XX. figs. 1, la) club-shaped, consisting of a very small, globular body 

 perched on the end of a slender stalk. From various parts of the body radiate long, .slender 

 processes. The stalk is short, and at the bottom breaks up into a tuft of rootlets. 

 Diameter of body 2 mm.; length of stalk and rootlets 12 mm. (these measurements 

 were taken from the smaller of two specimens). Colour in spirit pale yellow. 



Skeleton. — The skeleton consists of a main axis of spiculo-fibre, breaking up below 

 into a number of smaller fibres forming the rootlets, and giving off above a number of 

 radiating fibres which project for a considerable distance beyond the body of the 

 sponge. 



Spicules. — (a) Megasclera ; slender styli, sometimes slightly tylostylote, varying in 

 length according to their position in the sponge. In the main fibre of the skeleton 

 they measure about TO by 0-022 mm.; numerous smaller ones occur scattered loosely 

 through the soft parts of the sponge. (b) Microsclera; (l) numerous isochelae 



