sponges from the Atlantic Ocean. 409 



sketched these spicules, so that the record of them is not lost 

 and is herewith given (Pi. XII. fig. 8). Now, I am in the 

 habit of mounting a portion of a calcareous sponge in a dry 

 cell, where it may be considered to be almost imperishable with- 

 out accident. These spicules were respectively about 50- and 

 90-6000ths inch long and l-6000th inch broad, while the 

 barbs immbercd about sixteen, and the terminal inflation in 

 one presented no spines. To what variety of Grantia ciUata, 

 if to any in ])articular, they appertained I cannot state, as I can 

 only say that up to the time they were mounted I knew of no 

 other kinds of calcareous sponges on this beach, and therefore 

 they could be only the kinds mentioned ; but I have in vain 

 sought for such spicules since, although I have examined 

 many specimens of Grantia ciliata, taken from the same kind 

 of seaweed, similarly thrown up on the beach here, as the 

 specimen came from to which these spined spicules must 

 have belonged. 



The next instance (for they are not common) that I have 

 observed of this kind of anchoring-spicule occurring in a 

 calcareous sponge is that figured by Hiickel in ' Die Kalk- 

 schwiimme,' 1872 (Atlas, pi. 50. fig. 1), under the name of 

 Syculmis synajyta (previously named by Schmidt in MS. 

 Sycurus synapta). This sponge, which is about \ inch long 

 in the body and about —^ inch thick [op. cit. vol. ii. p. 289), 

 is provided with anchoring-spicules of a peculiar kind, inas- 

 much as the free extremity is furnished with three spines or 

 claws, more or less directed to one side, and without terminal 

 inflation, while there are no barbs or spines on the other 

 part of the spicule, which is long and linear. The specimen 

 came from the Museum at Copenhagen, and originally from 

 the coast of Brazil {ojy. cit. vol. ii. p. 288). 



Thus we may infer that some at least of the tubular cal- 

 careous sponges, in addition to having a structure very mucli 

 like that of Euplectella in miniature, are also provided with 

 similar anchoring-spicules. 1 have sought for them in many 

 species since discovering them in the slide above men- 

 tioned, without having found any thing of the kind, until 

 coming to the one above mentioned, which was dredged up on 

 board the ' Porcupine.' I need hardly add that they should 

 be sought for in the posterior j)art of the sponge, or that 

 attached to the object on which it may have grown. 



There was but one other specimen of a calcareous sponge 

 dredged up on board the ' Porcupine;' and this is in a jar num- 

 bered 51, =440 fathoms, between the north of Scotland and 

 the Fiiroe Islands. It is in company with Polymastia brevis, 

 Bk., but so mutilated that nothing more can be made out of 



