178 Transactions of the Society. 



feathered portions of the derm spiculse, and the ends of some of the 

 long, silky, linear spiculae. 



Most of the smaller spiculae are punctate, as it were, at the 

 surface, near their sharp ends, and in none could I detect a canal. 

 Some of the quadriradiate kind have a knob in place of the fifth 

 limb. Neither hamate spiculae nor amphidisci exist. 



This wonderfully complicated little hexactinellid sponge has a 

 broad osculum, which in the specimen described, is in contact with 

 the lower glass of the confining cell. The spicular elements are 

 more delicate there. 



It happened that in removing this sponge — a matter of great 

 delicacy — some extraneous sponge-matter was accidentally included 

 in the osculum. Fortunately, it belonged to a continuous-fibered 

 hexactinellid, so it can be separated in the description from the 

 Lyssakine form which is now under consideration. 



Locality : North Atlantic, out of a calice of a Loj)hoheUa, in 

 deep water. 



The little form is characterized by the numerous primary 

 spicule, by the closeness of the meshes formed by them and 

 those slightly smaller, and by the presence of hexradiate spiculae 

 and long, linear, curved spiculas in the body. By the presence 

 of small hexradiates, quadriradiates, feathered hexradiates, and 

 long silky fibres in the derm. By the occasional projection 

 through the meshes, of the ends of linear, attenuate spiculae ; and 

 by the absence of a beard, roots, amphidisci, and hamate spiculae. 



If these characters are compared with those of some minute 

 Holtenia Carpenteri which were dredged by H.M.S. ' Porcupine,' 

 and carefully described by Sir Wyvdle Thomson, F.E.S., in the 

 'Phil. Trans.,' 1869, plate Ixxi., the distinctness of the forms will 

 become apparent. The following is an extract from the essay on 

 Holtenia, p. 717 : — 



" During the deep-sea exploring cruise of H.M.S. ' Porcupine,' 

 the dredge brought up from the depth of 725 fathoms, off the 

 mouth of the English Channel, several young specimens of Holtenia 

 Carpenteri W. T., with a sponge-body from 2 to 200 mm. in length. 

 The youngest specimens seemed only to have passed out of the 

 condition of gemmules. The contour of these young sponges is 

 more elongated and pyriform than that of mature examples. The 

 external wall consists of a single series of quinqueradiate spicules, 

 much more regular in form than those of the larger sponges. The 

 four secondary branches decussate nearly at right angles, and the 

 fifth branch is quite straight, and plunges into the sponge nearly 

 vertically. During the growth of the sponge, the spicules, while 

 enlarging greatly, become distorted and irregular in the distribu- 

 tion of their rays ; the smaller spicules of the sponge-body are like- 

 wise more regular, and a few examples were met with of the very 



