46 



in mind that the female and eggs of the same species are always illustrated enlarged on 

 the same scale. 



As the difference of size between the very small species (or rather those whose 

 adult females are very small), as Homoeoscelis minuta and H. mediterranea , and the very 

 large ones, as Choniostoma mirabile and Ch. Hansenii, is exceedingly great (s. above p. 24), 

 and the difference between the eggs not being greater as just stated, it follows that, with 

 equal proportion between fertility and volume, the large species lays manifold more eggs 

 than the small one. To abide by our example: the number of ovisacs in Homoeoscelis 

 amounting to about eight', in Choniostoma to about twelve, it is evident that in the small 

 species we find few, in the large ones numerous eggs in each ovisac, and this fact is indeed 

 proved by the following figures: in an ovisac of Homoeoscelis minuta are found only about 

 14 to 18 eggs, in H. mediterranea no more than about 6 to 10, whereas in a middle-sized 

 ovisac of Choniostoma mirabile I have counted 1057 eggs. If, in a smaller species, as e. g. 

 Spluer. dispar and S. modesta, the number of ovisacs increases to about twenty, or, as in the 

 latter species, to about twenty-eight, the quantity of eggs contained in an ovisac is naturally 

 rather small (pi. IX, fig. 3 e, fig. 3 c and fig. 2 c), whereas in the gigantic Sphcer. Munnopsidis, 

 of which species one specimen — consisting only of a half-emptied skin — was about 5 mm. 

 in diameter, the number of ovisacs may indeed amount to twenty, still the average number 

 of eggs in each ovisac (in this species I have found great variety in the size of ovisacs of 

 the same specimen) is nevertheless very great, as is shown quite distinctly in fig. 4a on pi. X. 



The entire bulk of eggs deposed by a female — as stated above — is always larger 

 than the animal itself after it has laid them, and it is often so marvellously large, compared 

 with the female , that we hardly understand the possibility of it (s. pi. XI, fig. 3 a). This 

 state of things, however, may be partly explained by the fact that the ovisacs are deposed 

 at certain intervals (about a possible deviation in Stenothocheres, see above), and that conse- 

 quently the eggs can be gradually developed in the female. If we find seven or eight 

 ovisacs in a female, the development of at least one or two of these is nearly always so 

 far advanced, that the larvae are in the Nauplius stage; where ten or eleven, or still 

 more, ovisacs are found, one or two of these usually contain almost or quite full-grown 

 larvae. The length of time which elapses between the laying of the first and of the 

 last ovisac in specimens containing a large number of these sacs, as Splicer, decorata 

 and the other species living in the marsupium of Cumacea, seems to be about equal 

 to that which the first laid ovisac requires for its development: the division of the 

 germ, the Nauplius stage, and the development of the larva with numerous limbs, though 

 I cannot tell how many days are required for this process. The two species which lay 

 the smallest number of eggs are the diminutive forms Homoeoscelis mediterranea and 

 Stenothocheres egregius, the former has as many as eight ovisacs containing in all 60 to 

 70 eggs, whereas St. egregius, as a rule, only lays about 30 eggs (I have found between 

 16 and 42 eggs, the latter number in an exceptionally large specimen). The largest species, 



