602 



COMPARATIVE ANATOMY 



Similar skeletal pieces 



somewhat of the consistency of cartilage. 



support the tentacles and their branches. 



Some insight into the chief anatomical features of the individuals will 



be gained from the figures (Figs. 472, 473). The principal differences 



between Ehabdopleura and Cephalo- 

 discus are: (1) the gill -slits are 

 wanting in the former; (2) there 

 are only two feathered tentacles ; 

 (3) the proboscis pores, i.e. the 

 pores of the coelom of the buccal 

 shield, are wanting. 



The genital organs are still 

 imperfectly known. In some speci- 

 mens a testicle tube, which runs 

 longitudinally and asymmetrically 

 along one side of the body, and 

 bulges out the body wall, has been 

 demonstrated : this tube opens out 

 near the anus. Ehabdopleura, like 

 Cephalodisctis, is a deep-sea form. 



Further research is needed be- 

 fore we can establish the exact 

 relationship of Cephalodiscus and 

 Ehabdopleura to the Bryozoa. 



Fio. 473. —Ehabdopleura Normani, 

 median longitudinal section, diasrammatic n. 

 (after Fowler). 1, Tentacle of one side, in- 

 dicated by dotted lines ; 2, anterior paired 

 coelom (collar coelom) ; 3, anus ; 4, posterior 

 paired or trunk coelom ; 5, hind-gut ; 6, mid- 

 gut ; 7, buccal cavity ; 8, mouth ; 9, anterior q._ 

 diverticulum of the buccal cavity (proboscidal 

 diverticulum) ; 10, coelom of the buccal shield 

 (proboscidal coelom) ; 11, buccal shield. 



Literature. 



J. AUmann. On Rhabdojileura, a new 

 form of Polyzoa, from decjj-sea dredg- 

 ing in Shetland. Quart. Journ. 

 Microsc. Sc. Vol. IX. 1869. 

 Herbert Fowler. The onorphology of 

 Ehabdopleura Normani Allm. Fest- 

 schrift zum Siebenzigsten Geburtstag R. 



Lcuckwrt's. 1892. 

 Sidney F. Harmer. A'ppcndix to M'Intosh : Report on Ccpihalodiscus dodccaloplius 



M'Intosh. Rep. Voy. of the "Challenger" Zool. Vol. XX. 1887. 

 E. R. Lankester. A contribution to the anatomy of Rhabdopletira. Quart. Journ. 



Microsc. Sc. Vol. XXIV. 1884. 

 W. C. M'Intosh. Report on Cephalodiscus dodecalopMcs irintosh, a neiv type of the 



Polyzoa, procured on the voyage of H.M.S. "Challenger." Rep. Voyage 



" Challenger" Zool. Vol. XX. 1887. 

 G. 0. Sars. On Ehabdopleura mirabilis. Quart. Journ. Microsc. Sc. Vol. XIV. 



1874. 



