ON THE GENUS LUCERNARIA. 277 
the male, even by the naked eye. The ovisacs are densely 
filled with ova, of about 0:037 mm. in size; the yolk is red- 
dish and coarsely granular, and often completely conceals 
the germinal vesicle and germinal spot, which are respectively 
0-015 mm. and 0:004mm. insize. Thespermatic tubes have, 
when immature, a tuberculated aspect, from the large granu- 
lar sperm-cells with which they are filled; when the product 
is mature, the tube presents a perfectly smooth appearance, 
and it then contains innumerable highly mobile spermatozoa 
(fiz. 18), which survive a long time in water, and have a nail- 
like head, 0-004—0-005 mm. in length, to the broader end of 
which is attached the long, thick, and rigid caudal portion. 
Among the numerous specimens of L. octoradiata which 
I have examined, there were as many male as female, which 
could not be distinguished by their form or size, but were 
readily detected by the colour of the generative organs, as 
before mentioned. Out of about twenty specimens collected 
of L. campanulata there were no females, all being males. 
In the latter species the generative organs differ, in some 
respects, in their appearance from those of L. octoradiata. 
The spermatic tubes (which alone, from the circumstance 
above related, I was able to examine) form, not spherical, but 
merely lobular projections, and whilst in L. octoradiata in 
the middle portion of the sexual organ there are always two 
spherical sacs lying close together, this is not the case in 
L. campanulata, in which the entire organ appears to be con- 
stituted of a:single ligulate, lobed cord. 
I had no opportunity of observing either the fertilisation 
or development, although the specimens lived for a week in 
my glasses. 
§ 2.—On the Systematic Place of Lucernaria. 
In this section I will first trace the genus Lucernaria 
through the classifications of various systematists, and then 
endeavour to determine under which order of animals it may 
be most correctly placed; and lastly, give a synopsis of all 
the species at present known. 
1. Historical review.—The genus Lucernaria was disco- 
vered and established by Otto Fr. Miiller, and about the 
same time it was met with in Greenland by O. Fabricius. 
This Greenland species was also first published by O. Miiller, 
though he did not recognise its affinity with his new genus, 
but placed it, though somewhat doubtingly indeed, amongst 
the Holothurie ; Milne-Edwards is therefore incorrect in 
