148 Descriptions of Preparations. 



47. Angular Sea-Cucumber {Cucumaria Pentactes), 



Forbes, 



Dissected so as to show its motor, digestive, respiratory, and reproductive systems. 



The integument has been divided down the middle line of the 

 inter-radial space of the dorsal bivium, and fastened out on either 

 side. Five double longitudinal muscular bands are seen to divide 

 the body-walls into a corresponding number of antero-posteriorly 

 running zones, upon which the external circular muscular coat 

 is very well seen. In the interval between the two factors of 

 each double band is lodged the longitudinal water- vascular ambu- 

 lacral vessel in all the pneumonophorous Holothurioidea, whether 

 they possess ambulacral feet, or, as the Molpadidae, are devoid of 

 them ; and, as in all Holothurioidea without exception, the longi- 

 tudinal nerve-cord is to be found lying in the longitudinal plane 

 corresponding to the interval between the two muscular bands im- 

 mediately beneath the cutis ; and, as in the families which possess 

 longitudinal ambulacral vessels, between the cutis and those vessels. 

 The longitudinal muscles are prolonged from the region of the 

 mouth, where they are inserted into the integument near its 

 junction with the commencement of the digestive tract, down to 

 the anus ; and in the Dendrochirotae, to which family the Cucu- 

 mariae belong, each longitudinal muscle gives off a long shp, 

 which passes to insert itself into the corresponding radial ossicle 

 of the calcareous ring. In this specimen the slip given off is much 

 thicker than the radial muscle itself; indeed, the slightness of the 

 radial muscles, as well as the possession of these slips, is one of the 

 many points in which the Dendrochirotae differ from the Aspi- 

 dochirotae. On either side of the radial muscles the ampullae, 

 which in Dendrochirotae are not usually present in their tentacular 

 ambulacra, are seen arranged alternately. The radial water-vessels 

 with which these ampullae and the sucker-like feet are in con- 

 nection, pass forward to join the circumoral water-ring, through 

 an emargination in the anterior end of each of the radial ossicles 

 in the calcareous ring; and as the radial nerve-cords hold the 

 same relation to these ossicles, they have been viewed as homo- 



