LUCERNARI.E AND THE IK ALLIES. 7;} 



with tlie organization of other Acalepha?, than Avhen considered separately. Instead, 

 however, of taking up the history of the developineut of eacli organ, and foilowuig 

 it through all its stages, as is the more common method in embryology, we thmk 

 the interests of mori)hology will be subserved better if the morphogeiuc phases of 

 all the various organs, at any one period, are exhibited in their fullest interde- 

 pendence. We regret that we have failed to raise the young from the egg. There 

 is an almost insuperable obstacle to doing so, because the parent does not thrive in 

 conMncment, and, again, the young are not pelagic, but follow tlie liabits of the 

 adult, and creep over the eel-grass from a very early period. The chances of finding 

 them in the latter condition, therefore, are few, because they are so small. Vt'e 

 have not succeeded in obtaining specimens but a little less than one-sixteentli of au 

 inch in diameter across the umbella. 



147. General Fcatnrcfi. — The minutest individuals that we have met with, had 

 already four or five tentacles in each group, and measured not quite one-sixjeenth 

 of an inch across the umbella. At this time not a trace of the reproductive organs 

 is to be seen (_//'/. 121); but they appear soon after, as will be shown in the next set 

 of phases that come under our notice. The specimens upon which our investiga- 

 tions were made were found about the middle of September, although we have 

 discovered young of the same size two or three weeks earlier. The form of the 

 umbella is so nearly circular that its slightly octangular contour scarcely attracts 

 notice. The great prominence of the thickened, colletocystigerous portions of the 

 anchors (a) renders them so conspicuous that they seem to be the true angles of 

 the umbella. In profile, the body is much less cyathiform than in the adult, the 

 umbella being so strongly flattened as to approximate quite closely to a T-form. 

 The peduncle is proportionately very thick, so that, as a whole, the body is far less 

 slender tliau the adult. As to colors, they vary as much as at any other time of 

 life, but they are by no means so intense as at the latest periods. ^ 



148. 77(6 ^)roio6'c<s stands exactly in the same relative position, and is as dis- 

 tinctly four-sided as that of the adult, but is proportionally much thicker. Its 

 butresses, however, are not so prominent. The main peculiarity of the interior 

 of the umbella proper is the great thickness of t\\G pariltiotis (ij,^), and the very 

 considerable breadth of the passages, between the four chambers, across the distal 

 ends of the partitions. The peduncular camera; are singular for their total sejja- 

 ration from each other at their posterior ends, and they do not extend so far forward 

 as in later periods. This, then, leaves the peduncle partially monocamerous, and 

 leads one to suspect that, at a much earlier period, it is altogetlier so. Tliis 

 feature, no tloubt, will serve among others as an embryonic crlferiott, to determine 

 the relative rank of the members of this order. The monocamerous genera Lxcer- 

 naria and Cah-adosia, from tliis point of view, rank lower than Ilallcl/jsfus, and 

 we would add that in other respects they confirm this testimony. 



149. The Tentacles {fi<js. 121, 122, Nos. 1, P etc. to 4^).— At this period of 

 development the prehensile organs are in such a condition as enables us, better 

 than at any other time, to ascertain their taxif^ and mode of succession, as they 

 increase in numbers. As may be judg(>d from their ndative position, there is every 

 probability tluit at au earlier time but one tentacle terminated each corner of the 



10 February, 1878. 



