28 THE VOYAGE OF H.M.S. CHALLENGER. 



porting substance also varies. In Corattimorphus the cartilage-like consistency is 

 caused by a homogeneous matrix, which is richly excreted, and within which traces of a 

 fibrous tissue may still be recognised. In the specimen first described from Station 157 

 the fibrous mass is indistinct (PI. IX. fig. 11) ; on the other hand, in the last-named three 

 specimens (fig. 12) it is very distinct and sharply separated from the homogeneous funda- 

 mental substance, so that the latter forms a special layer contiguous to the endoderm. 



Numerous small, ramified cells ai*e scattered in the supporting lamella ; some of 

 these contained vacuoles and a single space, filled with fluid, and surrounded by a thin 

 protoplasmic layer containing the nucleus. The vesicles of the cells were large and 

 numerous in the first specimen, but easily overlooked in the others, as they were rarely 

 met with and small in diameter. 



The last-named diversity may be explained by admitting that the specimens are of 

 different ages, an admission which is supported by the difference in size, and which may 

 also explain differences in the muscular system, viz., that the ectodermal muscular layer 

 is a smooth lamella in the three smaller specimens, whilst in the larger one it is finely 

 folded. It is, however, advisable, under existing circumstances, to include all the four 

 individuals under the same name. 



Finally, the specimen described by Moseley had a somewhat different shape, 

 inasmuch as the pedal disk was only half as large as the oral disk, so that the side walls 

 of the body diverged as in an inverted cone. But as it had the longitudinal swellings 

 on the wall described above, and the number and arrangement of the tentacles were 

 exactly the same as in the specimen on which my description is founded, I did not 

 consider it to the purpose to divide the material into two species. 



Corattimorphus profundus, Moseley (PI. II. figs. 2 and 3). 



Corattimorphus profundus, Moseley, 1877, Trans. Linn. Soc, ser. ii., Zool., voL i. p. 300. 



Number of the intermediate tentacles limited to twelve, number of the marginal 

 tentacles, forty-eight. Mural membrane marked by longitudinal furrows corresponding 

 to the insertions of the septa. 



Habitat,— (a) Station 293. November 1, 1875. Lat. 39° 4' S., long. 105° 5' W. 

 Depth, 2025 fathoms. One specimen. (6) Station 300. December 17, 1875. Lat. 33° 

 42' S., long. 78° 18' W. Depth, 1375 fathoms. One specimen. 



Colour. — (Described from life by Moseley) in b, ochre-yellow, with dark radial madder- 

 coloured streaks, which are wanting in a. 



Dimensions. — Height, 0*8 and 2"5 cm. ; breadth of the oral disk, 32 and 7"0 cm.; of 

 the pedal disk, 1'7 and 4*5 cm. 



The characteristics by which Corattimorphus profundus is distinguished from 

 Corattimorphus rigidus are of a subordinate nature, so that I can include them in a short 



