BRITISH SPONGIAD^E. 31 



or Grantia botryoides of Fleming ('British Animals/ p. 525). 

 Montagu also states that the spicula of L. botryoides are 

 more than four times as large as those of his S. comjrficata, 

 while the spicula of the species under consideration are not 

 quite so stont at the bases of the radii, but are very much 

 larger than those of Grantia botryoides of Fleming, and that 

 author, who sent the specimens to Montagu, repudiates his 

 species. Dr. Grant, who also treats of S. complicata of 

 Montagu in his paper " On the Structure of some Calcareous 

 Sponges,"* likewise received his specimens from Dr. 

 Fleming. Dr. Johnston, also, with good reasons for his 

 conclusion, rejects Montagu's species as but a variety of 

 S. botryoides. Under these circumstances I think it is 

 better to reject the term complicata, and to adopt that of 

 contorta for the species under consideration. 



The form of this sponge is so distinctly different from 

 that of L. botryoides that, with the assistance of a lens of 

 two inches' focus, it cannot be well mistaken for that species, 

 which, although they are frequently congregated in groups, 

 have not apparently the habit of uniting together in one 

 mass by inosculation, while L. contorta always appears to 

 consist of a mass of contorted inosculated fistulas. Besides 

 this variation in external form, there is a distinct difference 

 existing between the skeleton spicula of the two species, for, 

 although both are equiangular triradiate, their proportions 

 are*very different from each other, those of L. botryoides 

 being proportionally much stouter and having much shorter 

 radii than those of L. contorta. The rays of the former 

 also attenuate rapidly and regularly from base to apex, 

 while those of the latter retain nearly the same diameter, 

 or are attenuated very gradually until near the apices, and 

 are then more suddenly acuminated, so that when the eye 

 has become familiarised with the two the species may be 

 readily decided by the forms of the spicula only. The 

 external surface of L. contorta is also sparingly furnished 

 with recumbent acerate spicula, mostly disposed in a longi- 

 tudinal direction, and I have never observed like spicula 

 on the surface of L. botryoides. 



* 'Eilinb. Med. Phil Journ.,' i, 169. 



