390 SELECTED NOTES FROM 



No. 9 is a transverse section of one of the arms of the common 

 star-fish, Uraster rubens, and No. lo a longitudinal section of the 

 same, displaying very clearly some of the wonderful arrangements 

 of the star-fish group. 



No. IT, a ventral section through Asterina gibbosa, one of the 

 smaller species of the star-fish family. 



No. 12, anchors and plates of Synapta digitafa in sitit. The 

 Synapta, or Sea Cucumber, belongs to the Echinoderms, but is a 

 transition form, connecting them with a more highly organised 

 group. Instead of having a stiff, shelly covering, through which 

 the organs of locomotion and prehension protrude, the Sea Cucum- 

 bers have an integument of a leathery consistency, and embedded 

 in the integument are to be found the various spines and plates so 

 well known in collections of microscopical preparations. In this 

 section they are seen in situ in a portion of the integument. 



William Pumphrev. 



Alcyonium digitatum.— Slide No. 8 is a very beautiful slide of 

 a polyp of Alcyonium diqifatum ("Dead Men's Fingers." "Cows' 

 paps," "Mermaids' Fingers," etc.). A. digitatum is typical of the 

 order Alcyonaria. It is met with as deep as seventy fathoms, but 

 is common in much shallower seas. It is widely distributed, and 

 is about equally abundant in tropical and temperate waters. The 

 Alcyonaria date back to the cretaceous period ; when dredged up 

 it is repulsive in aspect, and has thus earned its not very attractive 

 common names ; but placed in sea water, its sponge-like mass 

 distends, becomes pellucid, and from all parts of its surface num- 

 bers of exquisite polypes, of which the mounted specimen is one, 

 expand their star-shaped crown of tentacles, and the previously 

 uninviting mass becomes an object of extreme beauty. 



The tentacles are fringed, and within, circulating currents may 

 be observed finding their way up one side and down the other, 

 following the course of several fringes ; by the action of their 

 ciliated walls they seem to fulfil the function of a respiratory 

 system. 



The skeleton is sclero-basic and spicular, and is well shown on 

 the slide with a ^-in. objective. 



