the Oreensand convpared with those of existing Species. 127 



quadrilobate inflcition, as it is, for the most part, in Askonema 

 setidyalense. 



Still it is not with the plan on which the minute spicules of 

 sponges are -developed that we have to deal in the Haldon 

 deposit ; for, as already mentioned, their entire absence there 

 compels us to consider only the system of the larger spicules ; 

 and here we have one which is as distinctly quaternate in the 

 division of its head as the quadriradiate cross, with and 

 without shaft and extended arms respectively, in the large 

 spicules of Ilyalonema. 



Fig. 39 is a lateral view of one of these spicules, and fig. 38 

 the end view of its head, in which the central lines represent 

 the quadrifid branching of the axial canal. (The dotted lines, 

 for the most part, in these figures represent restored parts.) 

 Fig. 37, although on the same system as the last, much exceeds 

 the rest in size ; the central canals are enormously enlarged, 

 apparently at the expense of the walls of the spicule, which 

 are very thin ; but whether this was originally tlie case, or 

 subsequently produced during petrifaction, we will not consider 

 now, as the siibject (viz. the enlarged state of tlie canal in 

 many of the fossil spicules) will by-and-by come before us 

 separately. It will be observed that the ends of this quadrifid 

 head have also disappeared ; but a portion of the shaft, which 

 cannot be made apparent in the drawing, still remains ; nor is 

 it improbable that the arms Avere carried out, as in the long- 

 armed spicules of Hi/aJonema, to a much greater extent than 

 the dotted lines conjecturally indicated. 



Fig. 74, PI. X., is a lateral view of another specimen of 

 this spicule, showing the peculiar form of the arms ; and fig. 

 73 represents the head end of fig. 72, which, being smaller and 

 somewhat difterent from the rest, and furnished with a longer 

 shaft, may have belonged to another species ; while the short- 

 shafted ones may perhaps, by the union of their heads (for in 

 one instance I found tAvo together), have formed the surface of 

 some coral-sponge. Still, in the absence of all decisive evi- 

 dence in this respect, I propose for these spicules (which are 

 by no means uncommon, altliough not so plentiful as many of 

 the rest, and bear a remarkable resemblance to nails) the ge- 

 neric name " Gomphitcs.^^ Those with the shorter shafts and 

 more expanded heads I would call Govphites Parjittii, in 

 honour of Mr. Parfitt, who early recognized the value of these 

 fossils generally, who partly brought them to my notice, and 

 who subsequently wrote the valuable paper on them to which 

 I have alluded, in which is figured the peculiar form under 

 consideration. For the long-shafted one (fig. 72) Avith con- 

 tracted head I would propose the name of G. joarviceps. 



