290 BROOKS. [Vol. X. 



On p. 123, he says, "Among the more highly developed 

 Thaumantidae there are associated with the tentacles numerous 

 solid, oval, marginal clubs which are, in general, no longer than 

 the tentacular bulbs. On the constricted stalk of the club 

 there is often an ocellus." 



Fig. 4 shows part of the bell-margin of a specimen of 

 Laodice without accessory tentacles, from Woods Holl, magni- 

 fied 360 diameters (Bauch & Lomb, }i objective. 2. eye- 

 piece). The drawing is from an osmic acid specimen mounted 

 in balsam. Two of the marginal clubs are shown on the right, 

 alternating with the tentacles, and each placed upon the axial 

 or velar side of a sensory pad or thickening of the upper nerve 

 ring. Two tentacular bulbs are also shown, each with a large 

 ocellus and a number of scattered pigment spots upon its axial 

 or velar surface. Below these organs the vacuolated endoderm 

 cells of the circular canal are shown, below the level of the 

 transparent velum, which is not represented. On the left the 

 circular canal, one of the tentacles, and the sensory pads of two 

 of the marginal clubs are shown in optical section. 



Fig. 5 is part of a vertical section through the bell-margin 

 of a specimen from Woods Holl, of a Laodice which, like the 

 one shown in Fig. i, has an accessory tentacle in the radius of 

 each marginal club. The section is from an osmic acid speci- 

 men, and the drawing is magnified 1380 diameters (Bauch & 

 Lomb, ^2 homogeneous immersion, and i. eyepiece). 



The section passes through the base of one of the solid 

 accessory tentacles, a ; and through the axis of one of the 

 marginal clubs, b. The space marked c is the gelatinous bell ; 

 d is the exumbrella ; e, the subumbrella ; /, the velum ; g, the 

 cavity of the circular canal ; /^, the place of the lower nerve 

 ring, according to Hertwig ; /, the upper nerve ring and sensory 

 epithelium. 



Fig. 6 is a section through the attached end or stalk of a 

 club in a plane at right angles to Fig. 4, or horizontal. 



These sections show that the sense organ consists, like that 

 of the Narcomedusae, of two parts, a sensory pad formed by 

 the thickening of the sensory epithelium of the nerve ring, and 

 a free tentacle. The tentacle consists of a central axis of 



