REPORT ON THE MONAXONIDA. :*89 



In this species, again, the form of the " chess-man " spicule is, as usual, the dis- 

 tinguishing feature. The figures will show that it is really distinct from the corresponding 

 s[)icules in LatruncuUa apicalis and Latrunculia hrevis, although, as we have already 

 had occasion to mention, there is a slight variety of the latter which seems to form 

 a connecting link between the two ; the spicule in Latrunculia hocagei is lai-ger and 

 narrower than in Latrunculia hrevis, and the arrangement and relative sizes of the 

 whorls different. Latrunculia cratera, Socage, the original type of the genus, comes 

 near to our species in this respect, but in that species the whorls are much more minutely 

 and evenly dentate all the way round the rim, and the uppermost one is much smaller 

 than the others. According to Bocage's figures, also, the stylote spicule in Latrunculia 

 cratera is only 0'18 mm. long; but here we feel strongly inclined to think that there 

 has been some error, for we have found that the constancy in size of the stylote spicule is 

 a remarkable feature of the genus ; and a preparation in the British Museum, identified 

 by Schmidt with Latrunculia hocagei, while agreeing with the latter as regards the form 

 of the " chess-man " spicule, has the stylus about 0'5 mm. long. 



As regards external form it will be seen that Latrunculia hocagei is almost indis- 

 tinguishable from the Kerguelen specimen of Lati'unculia apicalis, and correspondingly 

 different from Latnmculia hrevis ; but in this case we are not inclined to set much value 

 on external form as a specific character, for we have already seen that the specimens of 

 Ijatrunculia apicalis from Kerguelen and from Station 320 respectively, differ in external 

 appearance ; indeed, to judge from the Challenger series of specimens of the genus, it 

 would seem that external appearance depends on the locality and that all the species 

 from the same locality tend to have a similar external form. 



Locality. — Kerguelen; depth, 10 to 70 fathoms. Two specimens. 



Latrunculia {f) acerata, Eidley and Dendy (PI. XXIX. figs. 3, 3a, 3&). 



1886. Latrunculia (?) acerata, Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, vol. xviii. 



p. 492. 



Sponge massive, amorphous, spreading. There is only one specimen in the collection, 

 and that in a very bad state of preservation. It forms a flattened, shapeless mass about 

 .'SO mm. long by 38 mm. broad and 13 mm. thick. Colour in spirit dirty brown. 

 Texture rather firm and compact. Surface very uneven, irregularly grooved ; at present 

 carrying a considerable amount of foreign matter. Dermal membrane distinct, strong, 

 supported by very numerous spicules ; in parts peeling off. Oscula (?). Pores scattered 

 through the dermal membrane (a fragment of the dermal membrane, which was boiled in 

 nitric acid for the sake of separating the spicules, appeared at the end of the process 

 uninjured, nnd showed the pores very distinctly). 



