Classification of the Spongida. 179 



extremities, which may be simply attenuated or conically 

 pointed, spearhead-like, or the same truncated, or simply 

 round, or more or less bulb-like ; or the ends may be more or 

 less microspined. Flesh-spicules for the most part of two 

 forms, viz. equianchorate and bihamate : the former shuttle- 

 like or naviculiform, or angulate (that is, bow-shaped) with fal- 

 cated spreading arms, or elliptical with linear arms ; the latter 

 or bihamate spicule simple, smooth, C-shaped, more or less 

 spirally contort. Sometimes the skeleton-spicule may be simply 

 cylindrical, curved and smooth, with rounded extremities ; and 

 sometimes the flesh-spicules may be altogether absent or not 

 discoverable. Forms for the most part incrnsting or massive, 

 lobsd, sometimes lobo-branched. 



Group 7. Hyndmanina. 



The same as the foregoing, but with dark brown sarcode 

 and an equianchorate like that characterizing the next group 

 (viz. the Esperina), together with a short, little, grotesque 

 form of the same kind, much curved upon itself, with the 

 ends unequal and each three-lobed, terminating in the centre 

 in a little point ; occasionally bihamates, C-shaped and contort. 



N.B. This may be viewed as a hybrid between the Hali- 

 chondrina and Esperina — that is, possessing the two forms 

 of skeleton-spicule of the former, together with the inequi- 

 anchorate and simple bihamate of the latter ; added to which 

 is the " grotesque spicule " above described, which again looks 

 like a hybrid between the inequianchorate and bihamate, but 

 nevertheless is a constant attendant, so must be regarded as a 

 distinct feature. 



Group 8. Esperina. 



Sarcode pale tawny, or yellow or vermilion-red when fresh. 

 Skeleton composed of an anastomosing reticulation of thick 

 round spiculo-fibre, of a greyish colour when fresh, opaque 

 white when dry, part of which is frequently naked or devoid 

 of sarcode, and the rest filled up with areolar sarcode. Fibre 

 of two kinds, viz. vertical or large and horizontal or small. 

 Surface even or undulating, presenting an exquisitely beauti- 

 ful polygonal, lacy or star-like reticulation, which is generally 

 characteristic of the group ; sometimes villous, or villous and 

 placoid. Vents distinct and scattered. Pores in the sarcode 

 which tympanizes the interstices of the dermal reticulation. 

 Texture of the skeleton coarse, fibrous ; that of the areolar sar- 

 code delicate, crumb-of-bread-like. Spicules of two kinds, viz. 

 skeleton- and flesh-spicules. Skeleton-spicule of one form 

 only, viz. sub-pinlike, with the inflated end for the most part 



