242 A MONOGRAPH OF THE 



9. Halichondria corrugata, Boicerbank. 



Sponge. Sessile, coating or parasitical. Surface smooth, 

 but uneven and corrugated. Oscula simple, dis- 

 persed, small. Pores inconspicuous. Dermal mem- 

 brane spiculous, strongly reticulated; spicula fusiformi- 

 acuate, stout, same size as those of the skeleton. 

 Skeleton. Reticulation stout, multispiculous ; spicula 

 fusiformi-acuate, stout, and rather short. Tension 

 spicula same as those of the skeleton, few in number. 

 Retentive spicula simple and contort bihamate, large, 

 few in number. 



Colour, Alive, blood-red ; dried, light red. 



Habitat. Diamond Ground, off Hastings, J. S. Bower- 

 bank. Douglass, Isle of Man, Mr. Joshua Alder. Island 

 of Herm, near Guernsey, Rev. A. M. Norman. 



Exam ined. Alive . 



I am indebted to Mr. Alder, of Newcastle-upon-Tyne, for 

 the first specimen I had seen of this species. It is ovoid in 

 form, the apex being the largest end. It is an inch in 

 height, and about half an inch in diameter. Mr. Alder 

 described the colour as red, when alive. Subsequently I 

 obtained, at Hastings, two living specimens from the 

 Diamond Trawling Ground. One of these enveloped a 

 branching Zoophyte for about the length of three inches, 

 and had a diameter of about half an inch. The surface of 

 this specimen was uneven, and much corrugated. The 

 other partially covered a small dead specimen of Desmacidon 

 (egagrojjhila, intermixed with portions of a Zoophyte, and 

 following the plane of the mass on which it was based ; it 

 assumed the form of an irregularly- shaped fan, an inch and 

 a quarter in height, and two and a quarter inches in 

 breadth, the greatest thickness not exceeding a quarter of 

 an inch. When alive, both surfaces were smooth, and pre- 

 sented the appearance of a deep blood-red flesh-like sub- 



