“Contributions to the Actinology of the Atlantic Ocean.” 365 
4. Deltocyathus Agassiz’, Pourtalés.—Lindstrém retains 
the modern name for this species, which has been exhaustively 
examined by Pourtalés and Moseley, and to the considera- 
tion of which I have given some care. Pourtalés sent me a 
specimen, and I recognized it as the well-known species 
Deltocyathus italicus, Michelotii sp., of the Tortona and other 
Italian Miocene deposits. Since then Pourtalés has acknow- 
ledged the fact *, and Moseley gives the proper name to the 
species in his ‘ Report on the ‘ Challenger’ Corals,” p. 145, 
in which he quotes the final decision of the lamented natu- 
ralist. It is a most variable species, and has a wide geogra- 
phical distribution. 
Lindstr6m considers some Hast-Atlantic specimens which 
have small paluli, an attached base, and thin walls to bring 
Sabinotrochus apertus, Duncan, within the species Deltocya- 
thus Agassizi. Moseley spared me the trouble of answering 
this most extraordinary conclusion t:—‘‘ After comparing 
Prof. Martin Duncan’s specimen of Sab¢notrochus apertus 
with the series of Deltocyathus, I conclude that Prof. Lind- 
strém’s conjecture that it is a variety of Deltocyathus Agassizt 
cannot be upheld. Sabcnotrochus differs in its general texture 
and in the thickness of its septa, in its fine wavy coste, and 
in the margin of the calicle being indented, also in the com- 
plete absence of pali, which are certainly not broken away.” 
Sabinotrochus and Deltocyathus are two perfectly distinct 
genera, and do not belong to the same group, even of the 
Turbinolide. Certainly Prof. Lindstrém’s critical method 
is the reverse of complimentary, and we do not want’ con- 
jectures. 
Next Prof. Lindstrém considers that a form described by 
Pourtalés (Trochocyathus Rawsont) “ may perhaps also belong 
to this species (Deltocyathus Agassizi= D. italicus), being pro- 
vided with septa and columella of the same shape” (p. 10). 
Pourtalés photographed the type of his species in pl. vi. 
figs. 7-10, of “‘ Zoological Results of ‘ Haslar’ Expedition’’f. 
Certainly the coste and pali of Yrochocyathus Rawsoni re- 
move it entirely from Deltocyathus. Itis a true Trochocyathus, 
allied to all forms with the tertiaries uniting to the secon- 
daries. After seeing Lindstrém’s criticism, Pourtalés still 
retained the form in the genus Trochocyathus, and considered 
that it was not without its affinities with Paracyathus. 
Lindstr6m compensates, however, for his unfortunate zoolo- 
* “Report on ‘ Blake’ Dredging Expedition,” Corals, by Pourtalés, 
1878-79, p. 101. 
+ Moseley, op. cit. p. 146. 
} Tl. Cat. Mus. Comp. Zool. Harvard, no. 8 (1874). 
