ECHINODEEMA.IA. 151 



specimen measuring 46 millim. in length has a greatest width of 

 20 and a greatest depth of 15 millim. The dorsal surface slopes 

 gradually to the two sides, which are marked off from the ventral 

 surface by the development along the lateral line of from three to six 

 short, conical, sharp denticle-like processes. Prom the median dorsal 

 line to this line the scattered suckers increase in number ; they are, 

 however, much more numerous on the ventral surface, and more re- 

 gularity of distribution is to be observed along the ventral median line 

 than in any other part. The suckers are provided with stout plates, 

 but no special terminal plate was detected. The calcareous plates in 

 the skin are on tha general plan of those in S. unisemita ; but the bars 

 do not appear to be so stout, and there may be at least seven pores. 

 The ten pieces of the calcareous ring are all equal, and the retractor 

 muscles are not especially strongly developed. As in S. wnisemita 

 there is, comparatively, a feeble development of the digestive and 

 respiratory organs ; but these characters, as well as the stiffness of 

 the tentacles, are rather points of generic importance. 



A more complete generic diagnosis wiU be made when the two 

 species have been ctaefully compared. 



Two young specimeus have the integument much thinner. 

 Port Jackson, 0-5 fms., where it is, as other collections show, 

 exceedingly common. Also from North Dunbar Island, China seas, 

 and from between Ball's Head and Goat Island (coll. Brazier) ; and 

 two dried specimens, purchased in 1848 of Mr. Cumhig, from Bris- 

 bane Water, IST. S. "W". ' 



In the definition of the genus given by Prof. Selenka there occur 

 the words "Korper mit einfachen Fiisschen bedeokt, die in der 

 rechten (oder linken) Planke in einer Doppelreihe stehen ; " and 

 the presence of this more distinct set of suckers is implied in the 

 specific term of the American species, unisemita. In the present 

 species, of which there is a good supply of specimens, I observe that 

 the double row occupies the middle of the trivium, but that it 

 varies considerably in the extent to which it is distinctly developed. 

 Some modification of the generic diagnosis must therefore be made, 

 and the suckers be spoken of as scattered over the body, but having 

 a tendency to form a regular double row in some part of the 

 trivium *. 



15. Stichopus variegatus. 

 , Semper, Hoi. p. 73. 

 A single, rather small specimen from Port MoUe. 



* Since working out this species I have had the opportunity of examining 

 another member of the genus from Kurrachee ; for S. mwrrayi see Proc. Zool. 



Soc. 1883, p. 61. . „ , , u • *v. u 1,-i. f 



Mr ■ Eamsay tells me that the natuiahsts of Sydney have been m the habit ot 

 regarding S. vcdHvm as the Holothwia spmosa of Quoy and Gaimard : this 

 determination cannot, I think, be accepted. 



