362 
PROFESSOR E. RAY LANKESTER. 
Amongst Trachomedusae, Craspedacustes finds its place in 
the Petasidse, which are characterised as ^ Trachomedusse with 
four radial canals, in the course of which the four gonads lie ; 
with a long tubular stomach and no stomach stalk/ 
Amongst Petasidse it is remarkable for the great number of 
its tentacles, which are all solid, and for its very numerous oto- 
cysts. Further it is remarkable amongst all Hydromedusae 
(velate Medusae exclusive of Charybdaea) for the fact that centri- 
fugal radiating canals pass from the otolithic concretions which 
they enclose into the velum where they end cacally, 
” The genus may be characterised as follows : 
“ Mouth quadrifid, with four per-radial lobes. 
Stomach long and tubular, projecting below the disc. 
'^Disc, flattened. 
Eadial canals, four terminating in the marginal canal. 
“Marginal (Eing) canal, voluminous. 
“ Centripetal canals- (such as those of Olindias, Geryonia, 
&c.) absent. 
“ Tentacles, solid ; in three sets, the horizons of the insertion 
of which are superimposed : — 
“ (1.) A highest (nearest the umbrella-pole) set of four large 
per-radial tentacles — primary tentacles. 
“(2.) A second tier of twenty-eighty or more medium*sized 
tentacles placed between these in four groups of seven — secon- 
dary tentacles. 
“ (3.) A third tier of one hundred and ninety-two or more 
small tentacles placed in groups of six between the last — tertiary 
tentacles. 
“Tentacle-rivets (Mantelspangen) connecting the roots of 
the tentacles with the marginal ring (Nesselring) are connected 
with all the tentacles. 
“ Otocysts placed along the line of insertion of the velum : 
about eighty in number, from sixteen to twenty between each 
pair of perradial tentacles, arranged in groups of two or three 
between the successive secondary tentacles. 
“Velar centrifugal canals are present, passing from the 
otocysts — one from each otocyst — into the velum, and there 
ending blindly. They appear to correspond in character to the 
centripetal canals found in other Trachomedusse in the disc. 
Their presence constitutes the chief peculiarity of the genus 
Craspedacustes, and may necessitate the formation of a distinct 
family or suborder for its reception. 
“ (The minute characters of the otocysts, and their relation to 
these canals, is now in course of investigation.) 
“ Ocelli are wanting. 
