ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
485 
More than seventy examples of the same author’s Pselopatides confundens 
were taken, and Benthodytes gelatinosa of Walsh is found to belong to 
the same genus, if the diagnosis be amended to contain forms with 
fifteen tentacles. The two genera just mentioned have no tentacular 
ampullae, and in this point three new genera of Aspidochirotae — Synal- 
lactes, Mesites , and Meseres — agree with them ; the first may be grouped 
together in the sub-family Synallactinae, while the remaining Aspido- 
chirotae form the Holothuri[i]nae. As the former sub-family exhibits 
points of affinity to the Elasipoda the author notes with satisfaction the 
confirmation of the view already expressed by him that the Elasipoda 
are descendants of the Aspidochirotae. 
Of the six Elasipod Psychropotinae, Benthodytes incerta, Psychropotes 
raripes , P. dubiosa, Euphronides tanneri, and E. verrucosa are new. Of 
the eight Deimatinae six are new, and for some of them new genera 
are formed — Scotodeima ( S . setigerum ) stands between Oneirophanta and 
Orphnurgus , Lsetmophasma (L fec.undum) is perhaps nearest to Pannychia, 
Capheira (O. sulcata') is placed with some doubt among the Deimatinae. 
Of the sub-family Elpidiinae one is a variety of Peniagone vitrea 
P. intermedia sp. n. is allied to Scotoanassa , and Scotoanassa gracilis is 
a new species. 
But of all the most interesting is the pelagic creature which forms 
the type of the new family Pelagothuriidae. It is distinguished by the 
development of a special swimming apparatus, which consists of a disc 
drawn out at the margin into long rays ; this is arranged round the 
circlet of tentacles, and calls to mind somewhat the base of the arms of a 
Cephalopod. There are no podia or ambulacral papillae ; the mouth and 
anus are terminal ; the body is circular. The tentacular canals arise 
from the well-developed radial canals, and each sends off a canal into 
the disc ; these disc-canals pass in a radial direction to the periphery of 
the disc, and extend to the tip of each ray. The longitudinal muscles 
of the body-wall are simple, and there are no retractors to the pharynx. 
There are no respiratory trees, ciliated organs, or organ of Cuvier. In the 
genus Pelagotlmria , which has thirteen to sixteen tentacles, there is no 
sign of any calcareous deposits. There is a single stone-canal, which 
opens directly to the exterior. The species P. natatrix is violet or purple 
in colour, 47 mm. long, while the length of the disc-rays is 50 mm. 
In the want of podia the Pelagothuriidae agree with the Synaptidae 
and Molpadiidae, from each of which they differ by some of the points 
already noted. Prof. Ludwig regards this new group as derived from 
the Elasipoda and as having become adapted to a pelagic mode of life. 
Of the nine species of Dendrochirotae seven are new, and for one a 
new genus, Sphserothuria, has to be formed. S. bitentaculata has an 
almost spherical form, and is covered with large plates, from each of 
which a strong freely projecting spine proceeds. The pair of tentacles 
which, in decaehirote forms, is generally smaller than the other four has 
completely disappeared, and of the remaining eight six are much shorter 
than the one right and one left one that are alone well developed. The 
podia are uncommonly small. Sphserothuria would appear to be derived 
from the Echinocucumis group of Cucumaria. 
Four of the six Molpadiidae are new, and belong respectively to the 
genera Caudinn , Trochostoma and Anlcyroderma. The family Synaptidm 
