REPORT ON THE ACTINIARIA. 105 



\v;ill ; the Willi covered with a tough cuticle ; no circular muscle ; tentacles fourteen in 

 number, of medium size, arranged in a single circle. 



Habitat.— Station 150. February 2, 1874. Lat. 52° 4' S., long. 71° 22' E. Depth, 

 150 fathoms. Two specimens. 



Dimensions. — Height, 27 cm. ; breadth, 0"8 cm. 



Colour. — (Determined from the spirit material) brownish-yellow. 



The Actiniae without pedal disk and with rounded, aboral end mostly vary in the 

 arrangement of their septa from the type predominating in the whole section, as 

 was explained in the Introduction, but this is rarely the case with the sessile forms. 

 Scytoplt'irus striatus, which represents a new species, furnishes one of the few examples of 

 this variation which have come under my observation. I found two specimens of it 

 in the Challenger material, so that I was able to examine one of them thoroughly. 



The body is very much elongated, and even in a state of contraction measures 2'7 cm. 

 in length, whilst it is only 0'8 cm. in breadth (PL III. fig. 6). The upper part of the 

 body is also inverted considerably (more than 0'5 cm.), as we see from the longitudinal 

 sections, a formation recalling Phellla peetinata, which has, however, an entirely different 

 structure. The surface is deeply incised by fourteen longitudinal furrows, which are the 

 more distinct because the surface is not soft as in the majority of Actiniae, but of a 

 leather-like consistency. This is owing to the presence of a strong cuticle, whose struc- 

 ture and relation to the underlying epithelium are best understood by transverse sections 

 (PL XIII. fig. 1). 



The cuticle consists of two layers; (l), a superficial layer, which hardly stains at all 

 in carmine, but keeps its natural tint, to which is due the yellowish colour of the entire 

 animal ; and (2), a deeper layer which becomes an intense red when treated with this 

 reagent. The two layers are tolerably well defined, at some points even by a smooth 

 line. The stratification parallel to the surface, usually found in euticular secretions, can 

 be recognised in the lower deposit, and striation perpendicular to the surface is also 

 present at many points. 



As the cuticle is of nearly equal thickness throughout, the longitudinal furrows of 

 the body, which show in transverse sections as deep indentations, are caused entirely by 

 the underlying epithelium and the supporting lamella. Both of these have an ecpial share 

 in causing the difference of level. The supporting lamella, a homogeneous fundamental 

 substance with scattered fusiform and branched cells, is very thick between each tw r o 

 furrows, and becomes thin below the indentations, and in the same w T ay the epithelium 

 is unusually high between the furrows, but reduced to an almost imperceptible layer below 

 them. Where the epithelial cells are elongated they are separated from one another by 

 interspaces ; they are easily turn in preparing transverse sections, so that an artificial 

 hollow space arises between the cuticle and the supporting lamella. 



The whole integument undergoes modification at numerous small, sharply defined 



(ZOOL. CHALL. EXP. —PART XV. 1882.) P 14 



