igojl Wilson — Sponges. 37 



Jophon indentatus, sp. no v. 

 Phakellia lamelligera, sp. now 

 Auletta dendrophora, sp. nov. 



In addition to the discovery of new forms, some results of 

 general biological interest have accrued from the study of the 

 collection, and are discussed or stated under the respective 

 species concerned. For convenience of reference the more 

 important of these facts may be here classified. 



Remarkable forms. Hyalonema pedunculatum is note- 

 worthy for the peculiar pedunculate form of body; Sclera ih- 

 umnopsis compressa for the shrub-like habitus in which it 

 resembles the hitherto unique Sclerothamnus clausii Marsh.; 

 Regadrella delicata for the character of the sieve-plate region, 

 which may be construed as representing- a simpler (although 

 not necessarily a more primitive) phylogenetic condition than 

 the otherwise closely similar Regadrella phoenix O. Schm. 



Distribution and Habitat. Thenea fenestrata O. Schm., 

 hitherto known only from the Atlantic and Caribbean Sea, is 

 now recorded for the Pacific. Some of the Hexactinellids 

 from great depths have been found to live clustering upon 

 one another: Caulophacus attached to root spicules of 

 tonema\ Bathydorus attached to root spicules of Hyalonema 

 and to stalks of Caulophacus or similar sponge. 



Morphology in general. Further evidence of a convincing 

 character has been gained that the Eurete and Farrea col- 

 onies are derived ontogenetically from simple cup-like forms. 

 The close similarity between the main afferent and effer- 

 ent canals and their apertures in Poecillastra tricornis is worthy 



of remark. The observations of Sollas and of Dendy on 



the occurrence of a peculiar fenestrated membrane (Sollas's 

 membrane) in the flagellated chambers of certain sponges 

 have been confirmed for two tetractinellid genera, Poecillastra 

 and Penares. 



Pathological phenomena in general. In Euplcctella skeletal 

 septa of a reticular character have been found crossing the 



