22 



HEMTCHORDATA 



CHAP. 



has been superseded by Bhabdopleura normani, AUman,^ based 





Fig. 9. — Cephalodisc^is clodecalophus, M'Intosli, Straits of Magellan ; A. small portion of 

 the common " house," x 1 ; a , a single individual, shown also as B, x 65 ; six of 

 the tentacular arms, belonging to the collar, are seen springing from behind the 

 proboscis or "buccal disc." This has a crescentic band of pigment parallel Avith its 

 posterior border, which conceals the month. The stalk, bearing a biid, which 

 already shows the beginning of two tentacular arms, is seen to the right. (After 

 M'iDtosh, B from Parker and Haswell.) 



^ Allman's name {Quart. J. Micr. Set. ix. 1869, p. 57 f. ) replaces that given 

 by Sars, because the latter gave no description by which the organism could be 

 recognised. 



