INVBKTEBRATE ANIMALS. O 



Sub-kingdom CCELENTERATA. 



(Frey & Leuckart.) 

 KoiKog, hollow; svTspov, the bowel. — Food-canal open to the 

 body-cavity. 

 Class HYDROZOA (Huxley). Internal cavity 

 simple. 



A monograph of the Hydrozoa is much needed. Ellis and Solander, ito, 

 and Lamouroux, Hittoire des Polypiers Flexibles, describe com- 

 paratively few of the species now known to science. Recent icorks 

 on the subject, such as " Contributions to the Natural History of 

 the United States, by L. Agassiz," are chiefly confined to local 

 productions. 



Sub-class HYDROIDA ; animals resembling the Hydra. 

 Group 10.— Order HYDRIDA-GYMNOCHROA (Hincks). 

 yuiJi,vos, naked; XP°^> ^^^ skin. Estimated number of 

 species : British, 4. 



H Drawings of several species of Hydra, and of the 

 modes of its reproduction by buds and ova. 



Group 11.— Order HYDRIDA-THECAPHORA (Hincks). 

 9y)x>), a sheath ; <pspcu, I carry. Sertularian and Cam- 

 panularian Zoophytes. Estimated number of species : 

 British, 92. Hincks. 



^ Series of British Zoophytes, collected and pre- 

 sented by H. H. H. Small series of Exotic 

 Zoophytes. Examples of Graptolites. 



Upper Compartment. 

 Drawings of ovarian vesicles of Sertidaria. 



Group 12.— Order HYDRIDA-ATHECATA (Hincks). « 

 without; QyjKYj, a sheath. Tubularian Zoophytes. Esti- 

 mated number of species : British, 70. 



H Specimens of the horny tubes of Tubularia, and 



of Eudendrium. 



Upper Compartment. 



Drawings of medusiform gonophores, &c., illus- 

 trating reproductive phenomena in Coryne. 



