LUCERN A RLE AND THEIR ALLIES. 5 



also be seen in the simplest generative sacs of Laomedca amphora, L. flexuosa, 

 etc., and, in other forms, rising through successive degrees of complexity to those 

 of Gonothyrea (Laomedea) Lovenii ^1//., whicli arc not only tipped with tentacu- 

 lar processes, as in Parypha and Thamnocnidia, but have within them a series 

 of longitudinal tubes, like those in the homologous organ of Tubularia indivisa. 



14. Gradually and methodically the progressive steps of complication lead on, 

 with a more and more marked separation of the genitalia from a direct relation to 

 the general mass, or even to the hydrte in particular, whilst a consentaneous 

 development gathers around them and brings them into immediate alliance with 

 an envelope whose morph is only a slightly varied repetition of that of the hydra, 

 but whose greater degree of complexity gives it a better claim to be ranked as the 

 highest among the cephalic nnhdifisions of the body. But the full aim of the train 

 of development is not divulged here ; its results only exemplify a part of it in the 

 predominance of the reproductive function and a differentiation of the nutri-tive 

 cavity into distinct channels of circulation, and the subordination of a definite 

 region of its periphery to a tentacular, prehensile office. Step by step, however, 

 all the elements of a complete organism are successively absorbed out of the 

 primitive hydra-mass, and remodelled into the foshion of a medusoid ; the repro- 

 ductive character has become a less obtrusive feature ; motion attracts attention 

 above all others ; prehension has full sway in the highly developed tentacles ; 

 and the latter point, like fingers, to the self-sustaining- power of the acalcphan 

 morph in the complete organization of the longitudinal and circular chymiferous 

 channels, opening into the receptive cavity of a highly flexible, proboscidiform 

 manubrium. The preliminary processes of fissigemmation are complete ; the primary 

 genesis of the ovum, in its integritij, is finished ; the primitive stock has become 

 difterentiated into two widely diverse varieties of one morpli, the Ji/jdroid ccplialoid 

 and the medusoid cephaloid. Such is the condition at wliich the hydromedusaria 

 of Coryniorpha, Hybocodon, Ectopleura (Tubularia) Dumortierii, Pennaria, Coryne 

 mirabilis, Margelis, Bougainvillia, and mnny Campanularia? have arrived previous 

 to the disintegration of their mass into the free pseudo-individual medusoids, and 

 their less independent contemporary homologues, the persistent hydroid cephalisms. 



15. The budding of the medusoid of Podocoryne, Lizzia, Hybocodon, and others 

 shows that the polyccphalic individual retains not only its homologieal identity, 

 but also its tendency to subdivide, in both of tlie parts which are separated from 

 each other*. In Clava we have a hydra cephaloid budding both medusoid cepha- 

 loids and hydra cephaloids, and the two are persistent and form a dimorphous body : 

 whereas in Hybocodon there is a hydra cephaloid budding only medusoid cepha- 

 loids ; but these latter bud other medusoid morphs, just as the liydra of Clava buds 

 hydroid morphs. We would remark here, in passing, that it cannot be said justly, 

 that a medusoid differs from a hydroid ess(?ntially, because the first has repro- 

 ductive organs and is the parent (direct) of the eggs ; for the simple globular sacs 

 of Clava, Hydractinia and others are just as much the genital organs of the 

 hydroid form, as the pendent sacs along the chymiferous tubes of the medusoid of 

 Tiaropsis, Eucope, Melicertum, etc., are the genitals of the latter. Since, now, 

 Lizzia was found by Claparede to have no intermediate hydra-state, the whole 



