592 DR. R. VON LENDENFELD ON THE SVriTEMATIC [DeC. 21, 



r With proper spicules in the supporting skeleton. 30. 



(17.) i Without proper spicules in the supporting 



[ skeleton (31.) 



f With uniformly distributed skeleton - reticu- 

 I lation and not very large subdermal caTities. 32. 



on J The skeleton consists of a dense axial reticu- 



i 



lation and isolated fibres extending from this 

 to the surface. Between these very extensive 

 subdermal cavities are situated (33.) 



22 f With gemmulse ; living in fresh water 37. SpongilUdte. 



\ Without gemnnilse 34. 



/Without flesh-spicules : fibres of the supporting 



I skeleton not spined d&. HomorJiaphid<B. 



34. ^ Flesh-spicules sigmata or spiral; no chelae 39. Heterorhaphida. 



I Flesh-spicules chelae ; when absent, fibres of 



( supporting skeleton spined 40. Desmacidonidig. 



(33.) No chelae 41. Axinellidce. 



(With small spherical chambers and oj)aque 

 ground-substance 35. 

 With large sac-shaped chambers and trans- 

 parent ground-substance (36.) 



Of- ( Without filaments in the ground-substance ... 37. 



( With filaments in the ground-substance 38. 



„_ f Skeleton-fibres with thin axial canal 42. 



I Skeleton-fibres tubular, with thick pith 43. A-plysinidce. 



(38.) Skeleton-fibre with thin axial canal 44. Hircinidts 



r Skeleton-fibres with thin axial canal ; reticulate 45. Spongelida. 



(36.) s Skeleton-fibrestubularwithtliickpith; dendritic 46. Aiylysillidee. 



1 Noskeleton 47. Halisarcidos. 



APPENDIX. 



LIST OF PUBLICATIONS RELATIIfG TO THE SPONGES. 



( Explanations of the Abbreviations used are appended.) 



1. .Slianus, Claudius. Uept I^mwv. Liber 8, Cap. 16, 



2. Agassiz, Alexander. (OnHexactinellids.) Bull. Mus.C.Z. 1868, p. 367 



(1868). 



3. Aldrovandi, U. De reliquis animahbus exanguibus nempe de Mollibus, 



Crustaceis, Testaceis et Zoophytis libri quatuor. Bononiaj, 1606. Fol. 

 (2nd ed. 1618 ; 3rd ed. 1623 ; 4th ed. 1642.) (1606-1642.) 



