164 bulletin: museum of comparative zoology. 



a medusa is thus even more striking than that of Leptodiscus medusoides 

 described by R. Hertwig,^ which is disk-shaped and lacks the velum. 

 It seems probable that the ring of granules found in Leptodiscus may be 

 the homologue of one of the two circlets found on either side of the 

 oblique band in the organism here described. 



In structural details it has much in common with Leptodiscus, but the 

 presence of the velum justifies its generic distinction in the family 

 Leptodiscidae. 



Craspedotella, gen. nov. 



Medusiform, with a velum at the margin of the bell-cavity which has 

 contractile walls. 



Craspedotella pileolus, sp. nov. 



Form low campanulate or cap-shaped, with a broad oblique band 

 (oM. bd.) at the base, bordered above and below by salient ridges and 

 continued toward the axis in a wide horizontal velum (vel.) with circu- 

 lar opening and entire margin. Its greatest diameter is located at the 

 ridge above the oblique band and is 1.5 to 2 times its height. The 

 bell opening is about 0.6 of the greatest diameter. A mass of richly 

 vacuolated granular plasma fills the apex and spreads laterally nearly to 

 the upper margin of the oblique band. Outside of this region the wall 

 of the bell is thin, hyaline, and somewhat rigid, and its plasma resembles 

 that of Lejitodiscus, but has well-marked radial strands in the oblique 

 band and in the velum. Within the central mass are found a large 

 fluid-filled vacuole (vac), a number of scattered food vacuoles {f\l. vac.), 

 and the small ellipsoidal nucleus (nuc). On the side of the bell, about 

 midway between the apex and the oblique band, appears the minute 

 pore of the flagellar sheath (flag, sh.) which extends about one half the 

 distance to the apex as a straight tube just beneath the surface. Near 

 the apex of the bell is the small cytopyge (ci/t^p'ij.), from which passes 

 a sinuous canal soon lost in the plasma. Foecal accumulations similar 

 to the scattered food particles were found in this canal. The food 

 appears to consist principally of minute Algae, or their spores. On the 

 under side of this bell at one side of the pendent mass of plasma is a 

 large vestibulum (vst.) bounded laterally by a sti-and of plasma from the 

 central mass. From its deeper end a tapering cytopharynx (ryi'2yh.) 

 sinks into the plasma and disappears near the apex of the bell in a 



1 Ueber Leptodiscus medusoides eine neue den Noctiliicen verwandte Flagellate. 

 Jena. Zeitscli. Bd. XI, pp. 307-323, Taf. XVII-XVIII, 1877. 



