365 



On a NEW SPECIES of SYCANDRA. 

 By R. J. Harvey Gibson, M.A., F.R.S.E. F.R.M.S., 



DEMONSTRATOR OF ZOOLOGY IN UNIVERSITY COLLEGE, LIVERPOOL. 



In the collection of worms dredged off the south end of the 

 Isle of Man, a specimen was found which, at first sight, 

 seemed to be extremely like the rare and interesting genus 

 Chcetoderma, and as such was labelled and put aside for 

 further examination. When, however, it was sectionized and 

 examined in detail, it was soon found to be a calcareous 

 sponge. 



In shape it is fusiform, the narrower end being provided 

 with a slight rim or fold (PL X, fig. 1). Its length is 

 8 mm. ; its breadth, at the narrow end, 1 mm. ; at its 

 thickest part, 3J mm. ; and at the terminal opening 1^ mm. 

 The entire surface of the body is studded with blunt-headed 

 calcareous spicules, which had at first suggested the possi- 

 bility of its being a Chcetoderma, 



In transverse section (PL X, fig. 2) the usual poriferal 

 characteristics appear, namely, a central cavity communi- 

 cating with the exterior by a series of closely placed ciliated 

 canals or chambers. The chambers are ovoid in horizontal 

 section, communicating with the interior and exterior by 

 slightly-constricted openings. These were well seen on the 

 sloughing of the superficial layer of tissue and spicules, 

 which took place when the animal was put in gum, as a 

 preliminary to freezing and sectionizing. In a section taken 

 from the centre of the thickest portion of this body, twenty- 

 eight of these chambers are seen in horizontal section. 

 They lie in a hyaline syncytium, containing a number of 



