7 24 THE ANIMAL KINGDOM. 



tacles, simple (Euchtora) or beset with lateral branches. All the peripheral vessels 

 end blindly. 



(i.) Mertensidae, body compressed in the stomachal plane : sub-tentacular 

 ctenophoral rows longer than the subventral ; Euchlora, Charistephane, &c. 



(ii.) Callianiridae, body similarly compressed : aboral pole with wing-like 

 processes ; Callianira (=-Eschscholtzia). 



(iii.) Pleurobrachiadae, body round in aquatorial section : ctenophoral rows 

 similar; Hormiphora ( = Cydippe in part), Pleurobrachia, Lampetia, Euplokamis. 



z and 3. Body compressed in the tentacular plane. Lateral tentacles con- 

 tained in a furrow of the oral margin. Principal tentacle may be present as in 

 Eucharis, or else wanting. Peripheral vessels communicate. Subventral cteno- 

 phoral rows longer than the subtentacular. Larval form a Mertensia-\ke, Cydippid. 



2. Lobatae, two lobes in the stomachal plane; Bolina, Deiopea, Eucharis, &c. 



3. Cestidae, body band-like ; Cestus, Vexillum. 

 II. Nuda. No tentacles. 



4. Beroidae, the vessels have lateral branches, and communicate inter se, as 

 well as by their branches ; Beroe, Neis, Idya, &c. 



' Ctenophorae ' Chun, Fauna und Flora des Golfes von Neapel, i. 1880; Bau 

 der Ctenophoren, R. Hertwig. J. Z. xiv. 1880, or ' Studien zur Blattertheorie,' iii. 

 Jena, 1880 : cf. L. Agassiz, Contribution to Nat. Hist. United States, iii. 1860, 



P- 155- 



Nets eordigera, von Lendenfeld, Z. W. Z. xli. 1885 ; Metamorphosis of Bolina 

 Chuni, Id. Proc. Lin. Soc. of New South Wales, ix. 1885, p. 929. 



Movements of ctenophoral plates, Krukenberg, Vergleich. Physiol. Studien i. 

 (3), 1880 : cf. Id. ibid, on Eimer. 



Summary of researches on Development, Allman, J. L. S. xvi. 1883 ; Gastrula 

 and formation of Mesoderm, Metschnikoff, Z. W. Z. xlii. 1885. 



CLASS ANTHOZOA. 



Marine Coelenterata either free or fixed, simple or colonial. The mouth 

 is an elongated slit in the centre of an oval disc or peristome which bears one 

 or more circles of hollow tentacles. It leads into an oesophagus or stomo- 

 daeum of some length which projects into the gastric cavity, and is united to the 

 body-wall by radial lamellate mesenteries. The generative organs are situate 

 on the mesenteries and are of endodermic origin. There are no organs of 

 special sense except isolated sensory cells. 



The body is usually columnar, rarely disc-like, terminated by the 

 peristome at one end, and in many simple Anthozoa by a pedal disc 

 or base at the other. But in most colonial forms its true shape is masked, 

 the oral part only remaining free. It has a distinctly radiate appearance, 

 but the axis of the mouth indicates a line of bilateral symmetry which 

 divides it into two halves. The two ends of this line may be anatomically 

 dissimilar owing to the structure of the corresponding mesenteries, hence 



