REPORT ON THE HOLOTHURIOIDEA. 51 



also be divided into a posterior rather convex portion and an anterior shorter, 

 narrower one, which makes an acute angle with the former. The neck-like part, 

 measuring from 8 to 10 mm., is several times narrower than the rest of the 

 body, and extends considerably below the ventral surface. On account of that neck- 

 portion being bent downwards and backwards, the anterior and posterior contours of the 

 body form almost a semicircle. The posterior third of the ventral surface is extremely 

 convex, and approaches the upper surface. If the neck-like part of the animal, when 

 living, is really as strongly bent downwards as I have thought, the mouth, being 

 situated at its extremity, must also be directed downwards. If, however, the bend of 

 the neck-like part depends only upon an accidental contraction, so that the neck in 

 its normal condition is extended forwards, then the mouth will attain a terminal 

 position in the anteriorly narrowing extremity of the body. The tentacles (PI. 

 XLIV. fig. 10) are cylindrical, equally large, measuring from 5 to 7 mm. in 

 length ; their terminal part is not remarkably enlarged, and is provided with retrac- 

 tile processes round the edge. The pedicels are sixteen in number, but are only 

 found on the posterior third of the ventral surface, where that is more obviously convex ; 

 the foremost pairs are cylindrical in form, and are of almost the same size as the ten- 

 tacles ; they thus exceed the posterior ones greatly in size, and are evidently situated 

 nearer the medio-ventral line. The transverse dorsal appendage docs not reach a 

 greater height ; its breadth on the contrary is considerable, approaching that of the 

 body. It seems to be produced by four processes, disposed in a transverse row, which 

 are webbed together by an extension of the skin, leaving only their tops free ; the two 

 middle processes are considerably larger than the others. Behind that lobe the dorsal 

 surface carries two pairs of extremely minute, almost invisible, processes. The glassy 

 body-wall is transparent and very hard and brittle, by reason of which the pedicels and 

 processes fall off on being slightly touched. The calcareous deposits (PI. XXXIV. 

 fig. 17) are very numerous and close-set ; their four arms, attaining the length of about 

 0'16 mm. or sometimes more, and having the aspect of being minutely spinose, are 

 sometimes almost straight and directed towards the inside of the body, sometimes on the 

 contrary extremely arcuated, especially at the ends. The processes are straight, finely 

 spinose, and very long, their number varying from two to four ; now and then only a 

 single process is to be observed. It seems as if a small pyramidal papilla encloses each 

 deposit. The oral disk contains deposits (PI. XXXIV. fig. 18) of more or less irregular 

 shape, their arms being almost straight or slightly curved ; besides these are found 

 some more or less straight, long spicula, which are either simple or irregularly branched. 

 The ends of the tentacles contain unbranched spicula, and irregular three- or four-armed 

 bodies with or without processes. The ends of the pedicels are provided with only a 

 few unbranched spicula. 



The five separated pieces of the calcareous ring bear a great resemblance to those of 



