150 



NEMOPSIS BACHEI. 



Fig. 223. 



only point which would throw some doubt upon this identification, is 

 the time of the year at which it appears in Charleston and in Vineyard 



Sound ; in the former place it is a Avinter species, 

 found in December, while at Naushon it Avas very 

 common in September. The marginal tentacles in- 

 crease in the same way as in Bougainvillia ; those 

 which are nearest the middle of the bulb, at its apex, 

 are developed first, and ne\v tentacles are constantly 

 growing near the base of the conical-shaped bulb. 

 (Figs. 228, 229.) They are at first slender-pointed 

 tentacles, but soon become rounded at the extremi- 

 ties, with sensitive eye-specks at the base, and change 

 into contractile tentacles, having a slight swelling at 

 the extremity ; this SAvelling, ho\vever, depends very much upon the 

 state of contraction of the tentacles. The Fig . 229 . 



adult frequently SAvim about Avith the 

 marginal tentacles contracted to mere 

 knobs, rising from the sensitive bulb (Fig. 

 229); during their movements, which are 

 rapid and powerful, the oral tentacles 

 (Fig. 230) are thrown up and doAA'n at 

 each pulsation with great violence, and 

 seem to be important appendages in di- 

 recting the motions of the animal. With 

 the exception that the tentacles, AA T hich are carried erect upon their 

 Fig 230 base, are not contractile like the others, and 



have a more clavate appearance (Figs. 227- 

 230), they differ in no AA 7 ay from the others. 

 There are eye-specks at the base of the erect 

 tentacles, as Avell as at the base of the con- 

 tractile ones, and the supposition that in 

 this genus the eyes Avere supported upon a 

 peduncle, like the eyes of a lobster, was 

 founded upon the dark club terminating this 

 pair of tentacles ; this color is due entirely 

 to a thickening of the extremity by contrac- 

 tion. Male specimens have been found meas- 

 uring more than half an inch in diameter. 

 The proboscis projects Avell beyond the line of the genital organs (Fig. 

 231) ; at first, in young stages, the genital organs occupy but a very 



Fig. 228. Nemopsis somewhat more advanced than Fig. 227, having the second and third set 

 of tentacles developed. 



Fig. 229. Magnified view of the sensitive bulb at the base of one of the chymiferous tubes, c. 



Fig. 230. Nemopsis in which the genital organs extend a considerable distance along the chy- 

 miferous tubes. 



