Dr. J. E. Gray on the CJassiJication of Sponges. 449 



Fam. 2. Desmacidonidse. 



Retentive spicules with a similar well-defined expanded 

 unilateral fluke at each end (aequibianchorate), free in the 

 sarcode, which also contains simple or bihamate spicules. 



Esperiadge, sect. 3, Gray, I. c. pp. 532 & 534. 



The flukes of the bianchorate spicules are of very different 

 shapes, as described in the paper above referred to ; and the 

 sponges are of very different forms, sometimes probably con- 

 taining more than one family. 



a. Ends of spicules divided into two or three spines. Iso- 

 dictya, EmpIocHS, Ancliinoe, Ificrociona, Dendoryx, Pronax^ 

 EutlrymuSj Desmacidon, Hamigeraj Hymedesmia^ Tereus^ Ho- 

 moeodictya, Ehlers. 



h. End of spicules concave, with a single central apical 

 tubercle. Coryhas. 



c. End of spicules cup-shaped. Ingallia. 



d. Spicule oblong, boat-shaped, concave on the sides. Na- 

 viculina. 



Fam. 3. Hamacanthidse. 



Retentive spicules with a definite compressed sharp-edged 

 fluke at each end, free in the sarcode. Sponge thin, coating. 



Esperiadae, sect. 4, Gray, I. c. pp. 532 & 538. 



Hamacantlia = Desmacella. 



Fam. 4, Gelliadae. 



Defensive spicules simj)le or contorted, without any bi- 

 anchorate spicules intermixed, free in the sarcode. 



Esperiadge, sect. 5, Gray, I. c. pp. 532 & 538. 



a. Defensive spicules filiform. Oellius, Biemna, AsycMs^ 

 Oceanopia (Norman). 



h. Defensive spicules clavate at the end. Dymnus [Damo). 



Order V. CORALLIOSPONGIA. 



Skeleton with hexaradiate spicules covering the surface or 

 imbedded in the sarcode, and very often simple or forked tri- 

 curvate spicules imbedded in the sarcode. The sarcode of this 

 family is very fluid or very slight, and scarcely visible in the 

 dried sponge. 



The hexaradiate stellate spicules, which are the essential 

 character of this order in the perfect state of development, 

 consist of an elongate needle-shaped spicule, which has four 

 diverging rays springing from about the centre of its length. 



